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Engineering â€ș Computational Mechanics

Laser Material Processing Techniques

Works Count: 56871

Description

This cluster of papers focuses on the use of femtosecond laser technology for micromachining transparent materials, exploring mechanisms of laser ablation, nanosurgery of cells and tissues, electron-phonon coupling, surface structuring, waveguide writing, and heat accumulation effects. The research covers a wide range of applications from materials processing to optofluidic lab-on-chips and photonic device fabrication.

Keywords

Femtosecond Laser; Micromachining; Transparent Materials; Ultrafast Dynamics; Laser Ablation; Surface Structures; Nanosurgery; Waveguide Writing; Heat Accumulation; Nanostructuring

Optical waveguides in crystalline dielectric materials produced by femtosecond‐laser micromachining

2013-05-17
Feng Chen , Javier R. VĂĄzquez de Aldana
Abstract Femtosecond‐laser micromachining (also known as inscription or writing) has been developed as one of the most efficient techniques for direct three‐dimensional microfabrication of transparent optical materials. In integrated photonics, 
 Abstract Femtosecond‐laser micromachining (also known as inscription or writing) has been developed as one of the most efficient techniques for direct three‐dimensional microfabrication of transparent optical materials. In integrated photonics, by using direct writing of femtosecond/ultrafast laser pulses, optical waveguides can be produced in a wide variety of optical materials. With diverse parameters, the formed waveguides may possess different configurations. This paper focuses on crystalline dielectric materials, and is a review of the state‐of‐the‐art in the fabrication, characterization and applications of femtosecond‐laser micromachined waveguiding structures in optical crystals and ceramics. A brief outlook is presented by focusing on a few potential spotlights.
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Laser-Induced Dynamic Gratings

1986-01-01
Hans Joachim Eichler , Peter GĂŒnter , Dieter Pohl

Pulsed Laser Deposition of Thin Films

2006-03-06
R.W. Eason
SECTION I. 1. Pulsed Laser Deposition of Complex Materials: Progress Towards Applications (D. Norton). SECTION II. 2. Resonant Infrared Pulsed Laser Ablation and Deposition of Thin Polymer Films (D. Bubb 
 SECTION I. 1. Pulsed Laser Deposition of Complex Materials: Progress Towards Applications (D. Norton). SECTION II. 2. Resonant Infrared Pulsed Laser Ablation and Deposition of Thin Polymer Films (D. Bubb & R. Haglund). 3. Deposition of Polymers and Biomaterials Using the Matrix Assisted Pulsed Laser Eveporation (MAPLE) Process (A. Pique). 4. In situ Diagnostics by High Pressure RHEED during PLD (G. Rijnders & D. Blank). 5. Ultra-fast laser Ablation and Film Deposition (E. Gamaly, et al.). 6. Cross-beam PLD: Metastable Film Structures from Intersecting Plumes (A. Gorbunoff). 7. Combinatorial Pulsed Laser Deposition (I. Takeuchi). 8. Growth Kinetics During Pulsed Laser Deposition (G. Rijnders & D. Blank). 9. Large Area Commercial Pulsed Laser Deposition (J. Greer). SECTION III. 10. Coating Powders for Drug Delivery Systems Using Pulsed Laser Deposition (J. Talton, et al.). 11. Transparent Conducting Oxide Films (H. Kim). 12. ZnO and ZnO-related Compounds (J. Perriere, et al.). 13. Group III Nitride Growth (D. O'Mahony & J. Lunney). 14. Pulsed Laser Deposition of High-Temperature Superconducting Thin Films and Their Applications (B. Schey). 15. DLC: Medical and Mechanical Applications (R. Narayan). 16. Pulsed Laser Deposition of Metals (H. Krebs). SECTION IV. 17. Optical Waveguide Growth and Applications (R. Eason, et al.). 18. Biomaterials: New issues and Breakthroughs for Biomedical Applications (V. Nelea, et al.). 19. Thermoelectric Materials (A. Dauscher & B. Lenoir). 20. Piezoelectrics (F. Cracium & M. Dinescu). 21. Ferroelectric Thin Films for Microwave Device Applications (C. Chen & J. Horwitz). 22. Films for Electrochemical Applications (M. Montenegro & T. Lippert). 23. Pulsed Laser Deposition of Tribological Coatings (A. Voevodin, et al.). SECTION V. 24. Laser Ablation Synthesis of Single-wall Carbon Nanotubes: The SLS Model (A. Gorbunoff & O. Jost). 25. Quasicrystalline Thin Films (P. Willmott).

Quantum Kinetics in Transport and Optics of Semiconductors

2007-12-09
Hartmut Haug , Antti‐Pekka Jauho
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Laser beam machining—A review

2007-12-06
Avanish Kumar Dubey , Vinod Yadava

Origin of Laser-Induced Near-Subwavelength Ripples: Interference between Surface Plasmons and Incident Laser

2009-11-12
Min Huang , Fuli Zhao , Ya Cheng +2 more
We show that short-pulse laser-induced classical ripples on dielectrics, semiconductors, and conductors exhibit a prominent “non-classical” characteristic—in normal incidence the periods are definitely smaller than laser wavelengths, which indicates that 
 We show that short-pulse laser-induced classical ripples on dielectrics, semiconductors, and conductors exhibit a prominent “non-classical” characteristic—in normal incidence the periods are definitely smaller than laser wavelengths, which indicates that the simplified scattering model should be revised. Taking into account the surface plasmons (SPs), we consider that the ripples result from the initial direct SP-laser interference and the subsequent grating-assisted SP-laser coupling. With the model, the period-decreasing phenomenon originates in the admixture of the field-distribution effect and the grating-coupling effect. Further, we propose an approach for obtaining the dielectric constant, electron density, and electron collision time of the high-excited surface. With the derived parameters, the numerical simulations are in good agreement with the experimental results. On the other hand, our results confirm that the surface irradiated by short-pulse laser with damage-threshold fluence should behave metallic, no matter for metal, semiconductor, or dielectric, and the short-pulse laser-induced subwavelength structures should be ascribed to a phenomenon of nano-optics.

Laser and Electron Beam Interactions with Solids

1982-02-01
N. Bloembergen , B. R. Appleton , G. K. Celler
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Ultrafast lasers—reliable tools for advanced materials processing

2014-04-11
Koji Sugioka , Ya Cheng
The unique characteristics of ultrafast lasers, such as picosecond and femtosecond lasers, have opened up new avenues in materials processing that employ ultrashort pulse widths and extremely high peak intensities. 
 The unique characteristics of ultrafast lasers, such as picosecond and femtosecond lasers, have opened up new avenues in materials processing that employ ultrashort pulse widths and extremely high peak intensities. Thus, ultrafast lasers are currently used widely for both fundamental research and practical applications. This review describes the characteristics of ultrafast laser processing and the recent advancements and applications of both surface and volume processing. Surface processing includes micromachining, micro- and nanostructuring, and nanoablation, while volume processing includes two-photon polymerization and three-dimensional (3D) processing within transparent materials. Commercial and industrial applications of ultrafast laser processing are also introduced, and a summary of the technology with future outlooks are also given. Scientists in Asia have reviewed the role of ultrafast lasers in materials processing. Koji Sugioka from RIKEN in Japan and Ya Cheng from the Shanghai Institute of Optics and Fine Mechanics in China describe how femtosecond and picosecond lasers can be used to perform useful tasks in both surface and volume processing. Such lasers can cut, drill and ablate a variety of materials with high precision, including metals, semiconductors, ceramics and glasses. They can also polymerize organic materials that contain a suitable photosensitizer and can three-dimensionally process inside transparent materials such as glass, and are already being used to fabricate medical stents, repair photomasks, drill ink-jet nozzles and pattern solar cells. The researchers also explain the characteristics of such lasers and the interaction of ultrashort, intense pulses of light with matter.
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Micromachining bulk glass by use of femtosecond laser pulses with nanojoule energy

2001-01-15
Chris B. Schaffer , A. Brodeur , J.F. Garcı́a +1 more
Using tightly focused femtosecond laser pulses of just 5 nJ, we produce optical breakdown and structural change in bulk transparent materials and demonstrate micromachining of transparent materials by use of 
 Using tightly focused femtosecond laser pulses of just 5 nJ, we produce optical breakdown and structural change in bulk transparent materials and demonstrate micromachining of transparent materials by use of unamplified lasers. We present measurements of the threshold for structural change in Corning 0211 glass as well as a study of the morphology of the structures produced by single and multiple laser pulses. At a high repetition rate, multiple pulses produce a structural change dominated by cumulative heating of the material by successive laser pulses. Using this cumulative heating effect, we write single-mode optical waveguides inside bulk glass, using only a laser oscillator.

Laser-induced breakdown and damage in bulk transparent materials induced by tightly focused femtosecond laser pulses

2001-10-09
Chris B. Schaffer , A. Brodeur , Eric Mazur
Laser-induced breakdown and damage to transparent materials has remained an active area of research for four decades. In this paper we review the basic mechanisms that lead to laser-induced breakdown 
 Laser-induced breakdown and damage to transparent materials has remained an active area of research for four decades. In this paper we review the basic mechanisms that lead to laser-induced breakdown and damage and present a summary of some open questions in the field. We present a method for measuring the threshold intensity required to produce breakdown and damage in the bulk, as opposed to on the surface, of the material. Using this technique, we measure the material band-gap and laser-wavelength dependence of the threshold intensity for bulk damage using femtosecond laser pulses. Based on these thresholds, we determine the relative role of different nonlinear ionization mechanisms for different laser and material parameters.

Femtosecond laser micromachining in transparent materials

2008-03-31
Rafael R. Gattass , Eric Mazur

Femtosecond laser-assisted three-dimensional microfabrication in silica

2001-03-01
A. Marcinkevičius , Saulius Juodkazis , Mitsuru Watanabe +4 more
We demonstrate direct three-dimensional (3-D) microfabrication inside a volume of silica glass. The whole fabrication process was carried out in two steps: (i) writing of the preprogrammed 3-D pattern inside 
 We demonstrate direct three-dimensional (3-D) microfabrication inside a volume of silica glass. The whole fabrication process was carried out in two steps: (i) writing of the preprogrammed 3-D pattern inside silica glass by focused femtosecond (fs) laser pulses and (ii) etching of the written structure in a 5% aqueous solution of HF acid. This technique allows fabrication of 3-D channels as small as 10 ÎŒm in diameter inside the volume with any angle of interconnection and a high aspect ratio (10‐Όm-diameter channels in a 100‐Όm-thick silica slab).

Temperature rise induced by a laser beam

1977-09-01
M. Lax
The spatial distribution of the temperature rise induced by a laser beam absorbed in a solid is reduced to a one-dimensional integral which is evaluated numerically. The solution for a 
 The spatial distribution of the temperature rise induced by a laser beam absorbed in a solid is reduced to a one-dimensional integral which is evaluated numerically. The solution for a general laser intensity distribution is specialized to the case of a Gaussian beam. A closed-form expression in terms of tabulated functions is obtained for the maximum temperature rise.

Heat Transfer Mechanisms During Short-Pulse Laser Heating of Metals

1993-11-01
Taiqing Qiu , C. L. Tien
This work studies heat transfer mechanisms during ultrafast laser heating of metals from a microscopic point of view. The heating process is composed of three processes: the deposition of radiation 
 This work studies heat transfer mechanisms during ultrafast laser heating of metals from a microscopic point of view. The heating process is composed of three processes: the deposition of radiation energy on electrons, the transport of energy by electrons, and the heating of the material lattice through electron-lattice interactions. The Boltzmann transport equation is used to model the transport of electrons and electron-lattice interactions. The scattering term of the Boltzmann equation is evaluated from quantum mechanical considerations, which shows the different contributions of the elastic and inelastic electron-lattice scattering processes on energy transport. By solving the Boltzmann equation, a hyperbolic two-step radiation heating model is rigorously established. It reveals the hyperbolic nature of energy flux carried by electrons and the nonequilibrium between electrons and the lattice during fast heating processes. Predictions from the current model agree with available experimental data during subpicosecond laser heating.

Short-pulse laser heating on metals

1992-03-01
Taiqing Qiu , C. L. Tien

Femtosecond, picosecond and nanosecond laser ablation of solids

1996-08-01
Boris N. Chichkov , C. Momma , Stefan Nolte +2 more

Photowritten optical waveguides in various glasses with ultrashort pulse laser

1997-12-08
Kiyotaka Miura , Jianrong Qiu , Hiroyuki Inouye +2 more
We show that permanent optical waveguides can be formed in various bulk glasses by photoinduced refractive index change with an ultrashort pulse laser. The waveguides were fabricated by focusing the 
 We show that permanent optical waveguides can be formed in various bulk glasses by photoinduced refractive index change with an ultrashort pulse laser. The waveguides were fabricated by focusing the laser beam through an microscope objective and translating the sample parallel to the axis of the laser beam. From the observations of intensity distributions in the output of guided light by a CCD camera, we demonstrated that permanent optical waveguides can be successfully formed in various glasses. In addition, from the analysis of a near-field pattern, it was confirmed that single mode waveguides of the graded index type can be formed by a writing technique using the ultrashort pulse laser.

Femtosecond electronic heat-transport dynamics in thin gold films

1987-10-26
S. D. Brorson , James G. Fujimoto , Erich P. Ippen
We have observed ultrafast heat transport in thin gold films under femtosecond laser irradiation. Time-of-flight (from-pump back-probe) measurements indicate that the heat transit time scales linearly with the sample thickness, 
 We have observed ultrafast heat transport in thin gold films under femtosecond laser irradiation. Time-of-flight (from-pump back-probe) measurements indicate that the heat transit time scales linearly with the sample thickness, and that heat transport is very rapid, occurring at a velocity close to the Fermi velocity of electrons in Au.

On the role of surface plasmon polaritons in the formation of laser-induced periodic surface structures upon irradiation of silicon by femtosecond-laser pulses

2009-11-15
Jörn Bonse , A. Rosenfeld , Jörg KrĂŒger
The formation of nearly wavelength-sized laser-induced periodic surface structures (LIPSSs) on single-crystalline silicon upon irradiation with single or multiple femtosecond-laser pulses (pulse duration τ=130 fs and central wavelength λ=800 nm) 
 The formation of nearly wavelength-sized laser-induced periodic surface structures (LIPSSs) on single-crystalline silicon upon irradiation with single or multiple femtosecond-laser pulses (pulse duration τ=130 fs and central wavelength λ=800 nm) in air is studied experimentally and theoretically. In our theoretical approach, we model the LIPSS formation by combining the generally accepted first-principles theory of Sipe and co-workers with a Drude model in order to account for transient intrapulse changes in the optical properties of the material due to the excitation of a dense electron-hole plasma. Our results are capable to explain quantitatively the spatial periods of the LIPSSs being somewhat smaller than the laser wavelength, their orientation perpendicular to the laser beam polarization, and their characteristic fluence dependence. Moreover, evidence is presented that surface plasmon polaritons play a dominant role during the initial stage of near-wavelength-sized periodic surface structures in femtosecond-laser irradiated silicon, and it is demonstrated that these LIPSSs can be formed in silicon upon irradiation by single femtosecond-laser pulses.

Self-Organized Nanogratings in Glass Irradiated by Ultrashort Light Pulses

2003-12-11
Yasuhiko Shimotsuma , Peter G. Kazansky , Jiarong Qiu +1 more
Periodic nanostructures are observed inside silica glass after irradiation by a focused beam of a femtosecond Ti:sapphire laser. Backscattering electron images of the irradiated spot reveal a periodic structure of 
 Periodic nanostructures are observed inside silica glass after irradiation by a focused beam of a femtosecond Ti:sapphire laser. Backscattering electron images of the irradiated spot reveal a periodic structure of stripelike regions of approximately 20 nm width with a low oxygen concentration, which are aligned perpendicular to the laser polarization direction. These are the smallest embedded structures ever created by light. The period of self-organized grating structures can be controlled from approximately 140 to 320 nm by the pulse energy and the number of irradiated pulses. The phenomenon is interpreted in terms of interference between the incident light field and the electric field of the bulk electron plasma wave, resulting in the periodic modulation of electron plasma concentration and the structural changes in glass.
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Mechanisms of femtosecond laser nanosurgery of cells and tissues

2005-11-14
Alfred Vogel , J. Noack , Gereon HĂŒttman +1 more

Microstructuring of silicon with femtosecond laser pulses

1998-09-21
Tsing-Hua Her , Richard Finlay , Claudia Wu +2 more
We report that silicon surfaces develop an array of sharp conical spikes when irradiated with 500 laser pulses of 100-fs duration, 10-kJ/m2 fluence in 500-Torr SF6 or Cl2. The spikes 
 We report that silicon surfaces develop an array of sharp conical spikes when irradiated with 500 laser pulses of 100-fs duration, 10-kJ/m2 fluence in 500-Torr SF6 or Cl2. The spikes are up to 40-ÎŒm tall, and taper to about 1-ÎŒm diam at the tip. Irradiation of silicon surfaces in N2, Ne, or vacuum creates structured surfaces, but does not create sharp conical spikes.

Inducing and probing non-thermal transitions in semiconductors using femtosecond laser pulses

2002-12-01
S. K. Sundaram , Eric Mazur

Time-resolved observation of electron-phonon relaxation in copper

1987-03-23
Hani E. Elsayed-Ali , Theodore B. Norris , M. Pessot +1 more
Amplified 150--300-fs laser pulses are applied to monitor the thermal modulation of the transmissivity of thin copper films. Non- equilibrium electron-lattice temperatures are observed. The process of electron-phonon energy transfer 
 Amplified 150--300-fs laser pulses are applied to monitor the thermal modulation of the transmissivity of thin copper films. Non- equilibrium electron-lattice temperatures are observed. The process of electron-phonon energy transfer was time resolved and was observed to be 1--4 ps increasing with the laser fluence.

Laser-induced periodic surface structure. II. Experiments on Ge, Si, Al, and brass

1983-01-15
Jeff F. Young , J. S. PrestĂłn , H. M. van Driel +1 more
We report the results of a detailed investigation into the properties of the periodic damage structure that can be produced on nominally smooth surfaces of solids when they are irradiated 
 We report the results of a detailed investigation into the properties of the periodic damage structure that can be produced on nominally smooth surfaces of solids when they are irradiated with a single beam of intense laser radiation. The study is primarily concerned with extracting information from the Fourier transform of the damage structure as observed via the Fraunhofer diffraction pattern produced by reflecting a cw laser beam from the surface. In particular, the patterns produced in Ge, Si, Al, and brass by pulsed 1.06- and 0.53-\ensuremath{\mu}m radiation are compared as a function of the angle of incidence and polarization of the beam. We find that all materials contain similar and much more intricate detailed structure than has been previously appreciated. Whereas periodic ripple patterns oriented perpendicular to the polarization at near-normal incidence are commonly reported, the diffraction patterns reveal that in fact there exists a continuous distribution of periodic structure oriented at all angles with respect to the polarization. At near-normal incidence there are two dominant sets of "fringes" running perpendicular to the polarization, while for a $p$-polarized beam incident at >35\ifmmode^\circ\else\textdegree\fi{} there exist three dominant periodic structures; two which run perpendicular to the polarization and one which is oriented parallel to it. For $s$-polarized light incident at angles >35\ifmmode^\circ\else\textdegree\fi{} there are two dominant patterns which form a cross-hatched pattern with axes oriented at 45\ifmmode^\circ\else\textdegree\fi{} to the plane of incidence. A study of the evolution of the patterns on a shot-to-shot basis indicates that both the initial and laser-induced surface roughness play important roles in the evolution of the damage. We conclude with a comparison of our experimental results with those predicted by the theory developed in the preceding paper. Excellent agreement is found.

Femtosecond laser ablation of silicon–modification thresholds and morphology

2002-01-01
Jörn Bonse , S. Baudach , Jörg KrĂŒger +2 more

Heat accumulation effects in femtosecond laser-written waveguides with variable repetition rate

2005-01-01
Shane M. Eaton , Haibin Zhang , Peter R. Herman +4 more
High-repetition rate femtosecond lasers are shown to drive heat accumulation processes that are attractive for rapid writing of low-loss optical waveguides in transparent glasses. A novel femtosecond fiber laser system 
 High-repetition rate femtosecond lasers are shown to drive heat accumulation processes that are attractive for rapid writing of low-loss optical waveguides in transparent glasses. A novel femtosecond fiber laser system (IMRA America, FCPA muJewel) providing variable repetition rate between 0.1 and 5 MHz was used to study the relationship between heat accumulation and resulting waveguide properties in fused silica and various borosilicate glasses. Increasing repetition rate was seen to increase the waveguide diameter and decrease the waveguide loss, with waveguides written with 1-MHz repetition rate yielding ~0.2-dB/cm propagation loss in Schott AF45 glass. A finite-difference thermal diffusion model accurately tracks the waveguide diameter as cumulative heating expands the modification zone above 200-kHz repetition rate.

Ultrafast-laser driven micro-explosions in transparent materials

1997-08-18
Eli N. Glezer , Eric Mazur
We initiate micro-explosions inside fused silica, quartz, sapphire, and other transparent materials using tightly focused 100 fs laser pulses. In the micro-explosions, material is ejected from the center, forming a 
 We initiate micro-explosions inside fused silica, quartz, sapphire, and other transparent materials using tightly focused 100 fs laser pulses. In the micro-explosions, material is ejected from the center, forming a cavity surrounded by a region of compacted material. We examine the resulting structures with optical microscopy, diffraction, and atomic force microscopy of internal cross sections. We find the structures have a diameter of only 200–250 nm, which we attribute to strong self-focusing of the laser pulse. These experiments probe a unique regime of light propagation inside materials at intensities approaching 1021 W/m2, the electron ionization that accompanies it, and the material response to extreme pressure and temperature conditions. The micro-explosions also provide a novel technique for internal microstructuring of transparent materials.

Pulsed laser vaporization and deposition

2000-01-01
P. R. Willmott , J. Robert Huber
Photons have many advantages for vaporizing condensed systems, and laser vaporization sources have a flexibility not available with other methods. These sources are applied to making thin films in the 
 Photons have many advantages for vaporizing condensed systems, and laser vaporization sources have a flexibility not available with other methods. These sources are applied to making thin films in the well-known technique of pulsed laser deposition (PLD). The vaporized material may be further processed through a pulsed secondary gas, lending the source additional degrees of freedom. Such pulsed-gas sources have long been exploited for fundamental studies, and they are very promising for film deposition, as an alternative to chemical vapor deposition or molecular beam epitaxy. The authors outline the fundamental physics involved and go on to discuss recent experimental findings.

Chirped multilayer coatings for broadband dispersion control in femtosecond lasers

1994-02-01
R. Szipöcs , Christian Spielmann , F. Krausz +1 more
Optical thin-film structures exhibiting high reflectivity and a nearly constant negative group-delay dispersion over frequency ranges as broad as 80 THz are presented. This attractive combination makes these coatings well 
 Optical thin-film structures exhibiting high reflectivity and a nearly constant negative group-delay dispersion over frequency ranges as broad as 80 THz are presented. This attractive combination makes these coatings well suited for intracavity dispersion control in broadband femtosecond solid-state lasers. We address design issues and the principle of operation of these novel devices.
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Bessel and annular beams for materials processing

2012-01-17
MartĂ­ Duocastella , Craig B. Arnold
Abstract Non‐Gaussian beam profiles such as Bessel or annular beams enable novel approaches to modifying materials through laser‐based processing. In this review paper, properties, generation methods and emerging applications for 
 Abstract Non‐Gaussian beam profiles such as Bessel or annular beams enable novel approaches to modifying materials through laser‐based processing. In this review paper, properties, generation methods and emerging applications for non‐conventional beam shapes are discussed, including Bessel, annular, and vortex beams. These intensity profiles have important implications in a number of technologically relevant areas including deep‐hole drilling, photopolymerization and nanopatterning, and introduce a new dimension for materials optimization and fundamental studies of laser‐matter interactions.

Femtosecond-tunable measurement of electron thermalization in gold

1994-11-15
Chi‐Kuang Sun , Fabrice VallĂ©e , L. H. Acioli +2 more
Femtosecond electron thermalization in metals was investigated using transient thermomodulation transmissivity and reflectivity. Studies were performed using a tunable multiple-wavelength femtosecond pump-probe technique in optically thin gold films in the 
 Femtosecond electron thermalization in metals was investigated using transient thermomodulation transmissivity and reflectivity. Studies were performed using a tunable multiple-wavelength femtosecond pump-probe technique in optically thin gold films in the low perturbation limit. An IR pump beam is used to heat the electron distribution and changes in electron temperature are measured with a visible probe beam at the d band to Fermi-surface transition. We show that the subpicosecond optical response of gold is dominated by delayed thermalization of the electron gas. This effect is particularly important far off the spectral peak of the reflectivity or transmissivity changes, permitting a direct and sensitive access to the internal thermalization of the electron gas. Using a simple rate-equation model, line-shape analysis of the transient reflectivity and transmissivity indicates a thermalization time of the order of 500 fs. At energies close to the Fermi surface, longer thermalization times \ensuremath{\sim}1--2 ps are observed. These results are in agreement with a more sophisticated model based on calculations of the electron-thermalization dynamics by numerical solutions of the Boltzmann equation. This model quantitatively describes the measured transient optical response during the full thermalization time of electron gas, of the order of 1.5 ps, and gives new insight into electron thermalization in metals.

Subwavelength ripple formation on the surfaces of compound semiconductors irradiated with femtosecond laser pulses

2003-06-19
A. Borowiec , H. K. Haugen
High-spatial-frequency periodic structures on the surfaces of InP, GaP, and GaAs have been observed after multiple-pulse femtosecond laser irradiation at wavelengths in the transparency regions of the respective solids. The 
 High-spatial-frequency periodic structures on the surfaces of InP, GaP, and GaAs have been observed after multiple-pulse femtosecond laser irradiation at wavelengths in the transparency regions of the respective solids. The periods of the structures are substantially shorter than the wavelengths of the incident laser fields in the bulk materials. In contrast, high-frequency structures were not observed for laser photon energies above the band gaps of the target materials.

Femtosecond laser-induced periodic surface structures

2012-07-16
Jörn Bonse , Jörg KrĂŒger , S. Höhm +1 more
The formation of laser-induced periodic surface structures (LIPSS) in different materials (metals, semiconductors, and dielectrics) upon irradiation with linearly polarized fs-laser pulses (τ ∌ 30–150 fs, λ ∌ 800 nm) 
 The formation of laser-induced periodic surface structures (LIPSS) in different materials (metals, semiconductors, and dielectrics) upon irradiation with linearly polarized fs-laser pulses (τ ∌ 30–150 fs, λ ∌ 800 nm) in air environment is studied experimentally and theoretically. In metals, predominantly low-spatial-frequency-LIPSS with periods close to the laser wavelength λ are observed perpendicular to the polarization. Under specific irradiation conditions, high-spatial-frequency-LIPSS with sub-100-nm spatial periods (∌λ/10) can be generated. For semiconductors, the impact of transient changes of the optical properties to the LIPSS periods is analyzed theoretically and experimentally. In dielectrics, the importance of transient excitation stages in the LIPSS formation is demonstrated experimentally using (multiple) double-fs-laser-pulse irradiation sequences. A characteristic decrease of the LIPSS periods is observed for double-pulse delays of less than 2 ps.
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Metal deposition from a supported metal film using an excimer laser

1986-08-15
J. Bohandy , B. F. Kim , Frank J. Adrian
A method for the direct writing of metal features from a metal film supported on an optically transparent substrate using a single pulse from a high-energy excimer laser (193 nm) 
 A method for the direct writing of metal features from a metal film supported on an optically transparent substrate using a single pulse from a high-energy excimer laser (193 nm) is presented. The technique eliminates the need for gas-phase precursors in many cases and is an inherently clean process. Results of copper depositions onto silicon substrates are shown to exemplify the technique and a mechanism for the process is proposed.

Persistent Spectral Hole-Burning: Science and Applications

1988-01-01
W. E. Moerner

Laser ablation and micromachining with ultrashort laser pulses

1997-01-01
X. Liu , D. Du , G. Mourou
The mechanisms of ultrashort-pulse laser ablation of materials are discussed, and the differences to that of long laser pulses are emphasized. Ultrashort laser pulses offer both high laser intensity and 
 The mechanisms of ultrashort-pulse laser ablation of materials are discussed, and the differences to that of long laser pulses are emphasized. Ultrashort laser pulses offer both high laser intensity and precise laser-induced breakdown threshold with reduced laser fluence. The ablation of materials with ultrashort pulses has a very limited heat-affected volume. The advantages of ultrashort laser pulses are applied in precision micromachining of various materials. Some femtosecond laser pulse micromachining results, including comparison with long pulses, are presented. Ultrashort-pulse laser micromachining may have a wide range of applications where micrometer and submicrometer feature sizes are required.

Simple technique for measurements of pulsed Gaussian-beam spot sizes

1982-05-01
J. M. Liu
A simple technique for in situ measurements of pulsed Gaussian-beam spot sizes is reported. This technique is particularly useful for measurements on highly focused beam spots. It can also be 
 A simple technique for in situ measurements of pulsed Gaussian-beam spot sizes is reported. This technique is particularly useful for measurements on highly focused beam spots. It can also be used for absolute calibration of the threshold-energy fluences for pulsed-laser-induced effects. The thresholds for several effects in picosecond-laser-induced phase transformation on silicon-crystal surfaces are calibrated with this technique.

Direct femtosecond laser surface nano/microstructuring and its applications

2012-08-08
A. Y. Vorobyev , Chunlei Guo
Abstract This paper reviews a new field of direct femtosecond laser surface nano/microstructuring and its applications. Over the past few years, direct femtosecond laser surface processing has distinguished itself from 
 Abstract This paper reviews a new field of direct femtosecond laser surface nano/microstructuring and its applications. Over the past few years, direct femtosecond laser surface processing has distinguished itself from other conventional laser ablation methods and become one of the best ways to create surface structures at nano‐ and micro‐scales on metals and semiconductors due to its flexibility, simplicity, and controllability in creating various types of nano/microstructures that are suitable for a wide range of applications. Significant advancements were made recently in applying this technique to altering optical properties of metals and semiconductors. As a result, highly absorptive metals and semiconductors were created, dubbed as the “black metals” and “black silicon”. Furthermore, various colors other than black have been created through structural coloring on metals. Direct femtosecond laser processing is also capable of producing novel materials with wetting properties ranging from superhydrophilic to superhydrophobic. In the extreme case, superwicking materials were created that can make liquids run vertically uphill against the gravity over an extended surface area. Though impressive scientific achievements have been made so far, direct femtosecond laser processing is still a young research field and many exciting findings are expected to emerge on its horizon.

Laser-Beam Interactions with Materials

1995-01-01
Martin von Allmen , A. Blatter

Optical ablation by high-power short-pulse lasers

1996-02-01
Brent C. Stuart , M. D. Feit , S. Herman +3 more
Laser-induced damage threshold measurements were performed on homogeneous and multilayer dielectrics and gold-coated optics at 1053 and 526 nm for pulse durations τ ranging from 140 fs to 1 ns. 
 Laser-induced damage threshold measurements were performed on homogeneous and multilayer dielectrics and gold-coated optics at 1053 and 526 nm for pulse durations τ ranging from 140 fs to 1 ns. Gold coatings were found, both experimentally and theoretically, to be limited to 0.6 J/cm2 in the subpicosecond range for 1053-nm pulses. In dielectrics, we find qualitative differences in the morphology of damage and a departure from the diffusion-dominated τ1/2 scaling that indicate that damage results from plasma formation and ablation for τ ≀ 10 ps and from conventional heating and melting for τ > 50 ps. A theoretical model based on electron production by multiphoton ionization, joule heating, and collisional (avalanche) ionization is in quantitative agreement with both the pulse-width and the wavelength scaling of experimental results.

Mechanisms of Pulsed Laser Ablation of Biological Tissues

2003-02-01
Alfred Vogel , Vasan Venugopalan
ADVERTISEMENT RETURN TO ISSUEPREVArticleADDITION / CORRECTIONThis article has been corrected. View the notice.Mechanisms of Pulsed Laser Ablation of Biological TissuesAlfred Vogel and Vasan VenugopalanView Author Information Medical Laser Center LĂŒbeck, 
 ADVERTISEMENT RETURN TO ISSUEPREVArticleADDITION / CORRECTIONThis article has been corrected. View the notice.Mechanisms of Pulsed Laser Ablation of Biological TissuesAlfred Vogel and Vasan VenugopalanView Author Information Medical Laser Center LĂŒbeck, Peter-Monnik-Weg 4, D-23562 LĂŒbeck, Germany, and Department of Chemical Engineering and Materials Science and Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine, California 92697 Cite this: Chem. Rev. 2003, 103, 2, 577–644Publication Date (Web):February 12, 2003Publication History Received12 September 2002Published online12 February 2003Published inissue 1 February 2003https://doi.org/10.1021/cr010379nCopyright © 2003 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views13075Altmetric-Citations1360LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (2 MB) Get e-AlertscloseSUBJECTS:Ablation,Bubbles,Lasers,Materials,Stress Get e-Alerts
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Laser-Induced Damage in Dielectrics with Nanosecond to Subpicosecond Pulses

1995-03-20
Brent C. Stuart , Michael D. Feit , Alexander M. Rubenchik +2 more
We report extensive measurements of damage thresholds for fused silica and calcium fluoride at 1053 and 526 nm for pulse durations $\ensuremath{\tau}$ ranging from 270 fs to 1 ns. Qualitative 
 We report extensive measurements of damage thresholds for fused silica and calcium fluoride at 1053 and 526 nm for pulse durations $\ensuremath{\tau}$ ranging from 270 fs to 1 ns. Qualitative differences in the morphology of damage and a departure from the diffusion-dominated ${\ensuremath{\tau}}^{1/2}$ scaling indicate that damage results from plasma formation and ablation for $\ensuremath{\tau}\ensuremath{\le}10$ ps and from conventional melting and boiling for $\ensuremath{\tau}>100$ ps. A theoretical model based on electron production via multiphoton ionization, Joule heating, and collisional (avalanche) ionization is in good agreement with experimental results.

Ablation-cooled material removal with ultrafast bursts of pulses

2016-07-12
Can Kerse , Hamit Kalaycıoğlu , Parviz Elahi +7 more
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Ultrafast laser processing of materials: from science to industry

2016-03-14
Mangirdas Malinauskas , Albertas Ćœukauskas , Satoshi Hasegawa +4 more
Abstract Processing of materials by ultrashort laser pulses has evolved significantly over the last decade and is starting to reveal its scientific, technological and industrial potential. In ultrafast laser manufacturing, 
 Abstract Processing of materials by ultrashort laser pulses has evolved significantly over the last decade and is starting to reveal its scientific, technological and industrial potential. In ultrafast laser manufacturing, optical energy of tightly focused femtosecond or picosecond laser pulses can be delivered to precisely defined positions in the bulk of materials via two-/multi-photon excitation on a timescale much faster than thermal energy exchange between photoexcited electrons and lattice ions. Control of photo-ionization and thermal processes with the highest precision, inducing local photomodification in sub-100-nm-sized regions has been achieved. State-of-the-art ultrashort laser processing techniques exploit high 0.1–1 ÎŒm spatial resolution and almost unrestricted three-dimensional structuring capability. Adjustable pulse duration, spatiotemporal chirp, phase front tilt and polarization allow control of photomodification via uniquely wide parameter space. Mature opto-electrical/mechanical technologies have enabled laser processing speeds approaching meters-per-second, leading to a fast lab-to-fab transfer. The key aspects and latest achievements are reviewed with an emphasis on the fundamental relation between spatial resolution and total fabrication throughput. Emerging biomedical applications implementing micrometer feature precision over centimeter-scale scaffolds and photonic wire bonding in telecommunications are highlighted.
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Laser-Induced Periodic Surface Structures— A Scientific Evergreen

2016-10-03
Jörn Bonse , S. Höhm , Sabrina V. Kirner +2 more
Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon and can be generated on almost any material upon irradiation with linearly polarized radiation. With the availability of ultrashort laser 
 Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon and can be generated on almost any material upon irradiation with linearly polarized radiation. With the availability of ultrashort laser pulses, LIPSS have gained an increasing attraction during the past decade, since these structures can be generated in a simple single-step process, which allows a surface nanostructuring for tailoring optical, mechanical, and chemical surface properties. In this study, the current state in the field of LIPSS is reviewed. Their formation mechanisms are analyzed in ultrafast time-resolved scattering, diffraction, and polarization constrained double-pulse experiments. These experiments allow us to address the question whether the LIPSS are seeded via ultrafast energy deposition mechanisms acting during the absorption of optical radiation or via self-organization after the irradiation process. Relevant control parameters of LIPSS are identified, and technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed.

Diagnosing the system for organizations

1986-02-01
Peter Checkland

Laser and Electron Beam Processing of Materials

1980-01-01
C. W. White , P. S. Peercy

Laser Annealing of Semiconductors

1982-01-01
J. M. Poate , James W. Mayer
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Influence of polarization angle on LIPSS formation and ablation efficiency in direct laser interference patterning of metals

2025-06-25
Felipe Almeida , Bogdan Voisiat , Ignacio Javier Tabares +2 more | Scientific Reports
Abstract This study explores the influence of the polarization angle on the formation of Laser-Induced Periodic Surface Structures (LIPSS) during Direct Laser Interference Patterning (DLIP) and its impact on ablation 
 Abstract This study explores the influence of the polarization angle on the formation of Laser-Induced Periodic Surface Structures (LIPSS) during Direct Laser Interference Patterning (DLIP) and its impact on ablation efficiency in stainless steel and aluminum 2024 substrates. Two pulse durations, 12 ps and 70 ps, with a laser wavelength of 1064 nm, are employed at varying accumulated fluences to evaluate their effects on the surface structuring process. The results demonstrate that the Low Spatial Frequency LIPSS (LSFL) orientation with respect to the line-like structures produced by two-beam DLIP is strongly influenced by the polarization angle and the alignment of DLIP features. In addition, the spatial period of LSFL in stainless steel remained relatively stable regardless of the polarization angle (~ 900–1000 nm), whereas in aluminum 2024, it exhibited significant variation, decreasing from approximately 920 nm to 506 nm as the LSFL rotated. The polarization angle also affected the reached structure depth at constant irradiation conditions, particularly in stainless steel, where greater depths were achieved when the LSFL aligned perpendicularly to DLIP lines (over 50% variation). These findings provide valuable insights for optimizing laser-based surface processing techniques for metallic substrates.

Study on the influence of preheating conditions on the fiber laser direct writing coloring of stainless-steel surface

2025-06-24
Boxin Lu , Boyuan Gao , Ping He +2 more | Journal of Laser Applications
Laser coloring of metal surfaces is widely studied for its diverse applications and significant advantages. This study examines the impact of preheating temperature on fiber laser coloring of 304 stainless-steel 
 Laser coloring of metal surfaces is widely studied for its diverse applications and significant advantages. This study examines the impact of preheating temperature on fiber laser coloring of 304 stainless-steel surfaces. The study compares and analyzes the effects of laser power, defocus distance, and scanning speed on color outcomes and microstructure. Spectral analysis of the reflection spectrum is performed using a spectrometer, and energy-dispersive x-ray spectroscopy analyzes surface composition elements. The changes in the color gamut range are analyzed comparatively. This research investigates the influence of preheating on the coloring mechanism. The results indicate that, under preheating conditions, the stainless-steel surface exhibits better color uniformity, higher saturation, a broader color gamut, and a higher proportion of oxide components, which are primarily related to the increased initial laser absorption rate and reduced thermal conductivity due to preheating temperature.

Controlling ultrafast, adaptable and synchronized cascaded scan systems for laser materials processing

2025-06-24
Felix Lange , Lucas de Andrade Both , Markus Zecherle +3 more | Optics & Laser Technology

Study on electromagnetic field assisted laser cutting on silicon wafer

2025-06-24
Xiaoqing Wang , Zhiwen Wang , Wenxuan Xi +1 more | Optics & Laser Technology

Advancing VCSEL integration with femtosecond laser microstructuring and 3D nanoprinting

2025-06-24
Athanasios Kyriazis , Salah Guessoum , Jeroen Missinne +3 more | Optics & Laser Technology

Crystallographic Dependence of Ultrafast Laser Induced Crack Generation in Single-Crystal Sapphire

2025-06-21
Liu Tongwei , Tang Haoxing , Xinyong Dong +2 more | Vacuum

Investigation of the strengthening mechanism of thermal-assisted laser material processing on the cutting performance of micro-textured tools

2025-06-20
Xinyu Li , Xin Tong , Shucai Yang +2 more | Journal of Manufacturing Processes

Extended depth-of-focus femtosecond laser pulses for flexible micromachining

2025-06-20
Alex K.‐Y. Jen , Tina Hayward , Anita Kumari +5 more | Optics Letters

Combined two-temperature method and coarse-grained molecular dynamic model in femtosecond laser ablation at large spatiotemporal scale

2025-06-19
Hengfeng Yang , Hong Shen | Journal of Manufacturing Processes

Fabrication of color code by femtosecond laser-induced nanostructures on the surface of metal films with yttria-stabilized zirconia substrate

2025-06-19
Xiaoyun Sun , Wenjun Wang , Chuanwei Zhang +1 more | Optics Communications

Hybrid High-Power Laser and Mechanical Drilling of Thick CFRP Laminates

2025-06-19
Jiwei Ren , Dongxu Cheng , Xiaoyang Sun +3 more | Journal of Manufacturing Science and Engineering
Abstract Thick carbon fiber-reinforced polymer (CFRP) composites are extensively used in aerospace industry, but conventional mechanical drilling often results in burrs, delamination, and significant tool wear. Laser processing introduces heat-affected 
 Abstract Thick carbon fiber-reinforced polymer (CFRP) composites are extensively used in aerospace industry, but conventional mechanical drilling often results in burrs, delamination, and significant tool wear. Laser processing introduces heat-affected zones (HAZ) and taper, while pulsed laser trepanning combined with mechanical drilling lacks efficiency for small holes in thick CFRP. This study proposes a high-power laser-mechanical hybrid drilling process, integrating short-duration high-power laser punching with mechanical drilling to reduce defects and tool wear. Experiments on 35mm-thick CFRP laminates explored the effects of laser and mechanical parameters on HAZ morphology, tool temperature, forces, and wear, elucidating material removal mechanisms. The hybrid process effectively controls HAZ size and taper through laser parameter adjustments and reduces tool temperature by 32.4% and cutting forces by 42.4% compared to mechanical drilling. It also minimizes burrs and delamination while reducing tool wear by 38.8% on secondary and 64.66% on primary cutting edges.

ANOVA Based Optimization of UV Nanosecond Laser for Polyamide Insulation Removal from Platinum Wires Under Water Confinement

2025-06-18
Danial Rahnama , Graziano Chila , Sivakumar Narayanswamy | Journal of Manufacturing and Materials Processing
Platinum wires, known for their excellent electrical conductivity and durability, are widely used in high-precision industries, such as aerospace and automotive. These wires are typically coated with polyamide for protection; 
 Platinum wires, known for their excellent electrical conductivity and durability, are widely used in high-precision industries, such as aerospace and automotive. These wires are typically coated with polyamide for protection; however, specific manufacturing processes require the coating to be selectively removed. Although traditional chemical stripping methods are effective, they are associated with high costs, safety concerns, and long processing times. As a result, laser ablation has emerged as a more efficient, precise, and cleaner alternative, especially at the microscale. In this study, ultraviolet nanosecond laser ablation was applied to remove polyamide coatings from ultra-thin platinum wires in a water-assisted environment. The presence of water enhances the process by promoting thermal management and minimizing debris. Key processing parameters, including the scanning speed, overlap percentage, and line distance, were evaluated. The optimal result was achieved at a scanning speed of 1200 mm/s, line distance of 1 ”m, and single loop in water-ambient, where coating removal was complete, surface roughness remained low, and wire tensile strength was preserved. This performance is attributed to the effective energy distribution across the wire surface and reduced thermal damage due to the heat dissipation role of water, along with controlled overlap that ensured full coverage without overexposure. A thin, well-maintained water layer confined above the apex of the wire played a crucial role in regulating the thermal flow during ablation. This setup helped shield the delicate platinum substrate from overheating, thereby maintaining its mechanical integrity and preventing substrate damage throughout the process. This study primarily focused on analyzing the main effects and two-factor interactions of these parameters using Analysis of Variance (ANOVA). Interactions such as Speed × Overlap and Speed × Line Distance were statistically examined to identify the influence of combined factors on tensile strength and surface roughness. In the second phase of experimentation, the parameter space was further expanded by increasing the line distance and number of loops to reduce the overlap in the X-direction. This allowed for a more comprehensive process evaluation. Again, conditions around 1200 mm/s and 1500 mm/s with 2 ”m line distance and two loops offered favorable outcomes, although 1200 mm/s was selected as the optimal speed due to better consistency. These findings contribute to the development of a robust, high-precision laser processing method for ultra-thin wire applications. The statistical insights gained through ANOVA offer a data-driven framework for optimizing future laser ablation processes.

Molecular dynamics simulation study on the ablative copper forming process at the atomic level by femtosecond laser

2025-06-18
Linyi Xie , Yuhai Li , Fei Wang +2 more | Journal of Manufacturing Processes

Analysis of fiber laser microgrooving characteristics of Ti6Al4V

2025-06-18
Sayan Doloi , Mohit Pandey , Bijoy Bhattacharyya | Journal of Micromanufacturing
Pulsed diode-pumped fiber lasers offer excellent performance for diverse micromachining applications across a variety of engineering materials, including superalloys, ceramics, and composites. Due to the extensive and promising applications of 
 Pulsed diode-pumped fiber lasers offer excellent performance for diverse micromachining applications across a variety of engineering materials, including superalloys, ceramics, and composites. Due to the extensive and promising applications of Ti6Al4V in various fields, including automotive, electronics, aerospace, and biomedical engineering, laser microgrooving on Ti6Al4V is in high demand today. The study examines how process variables, including laser power, scan rate, pulse rate, and number of passes, affect laser microgrooving characteristics like width, length, depth of microgroove, and heat-affected-zone width thickness. Experimental findings revealed that to create smooth grooves with lower heat-affected zone on titanium alloy, process parametric settings such as laser power of 10 W, pulse frequency of 90 kHz, scan rate of 30 mm/s, and two passes were recommended. Attempts were also made to create a microgroove on a cylindrical workpiece using the above set of process variables, but the rotation of the job is another critical factor that must be considered to achieve the desired groove geometry.

Laser-induced structural dynamics of a gold crystal in vacuum

2025-06-17
S. A. Aseyev , Б. Н. ĐœĐžŃ€ĐŸĐœĐŸĐČ , A. A. Ischenko +1 more | Vacuum

Simplified method for predicting melting and ablation process parameters during laser surface treatment of metals and alloys

2025-06-17
Yutaka Tsumura , Anna Paradowska , Andrei V. Rode +2 more | Journal of Applied Physics
In this paper, a simplified analytical solution to predict melting and ablation process parameter thresholds for short-pulsed laser irradiation is developed and applied to common metals and alloys, including aluminum, 
 In this paper, a simplified analytical solution to predict melting and ablation process parameter thresholds for short-pulsed laser irradiation is developed and applied to common metals and alloys, including aluminum, copper, titanium, stainless steel 316, and zirconium. The new approach utilizes material parameters at only two temperatures: room temperature and the material melting point, by introducing a new parameter called the Intensity Fluence Factor (IFF). Specifically, it considers density, specific heat capacity, thermal conductivity, and reflectivity to predict various thresholds for the given laser parameters (i.e., intensity and fluence). The IFF removes time dependency from the laser parameter to clearly demonstrate the temperature rise of the material, predicting phase transformation. This provides an initial predictive framework, offering a practical guideline for experimental setups. The generality and applicability of this method are examined through comparisons with Finite Element Method (FEM) models that incorporate fully variable temperature-dependent material properties. The Intensity Fluence Factor (IFF) introduced in this study and the associated prediction method demonstrate versatility across short-pulse laser processing conditions and material types. Furthermore, the derivation of this simplified analytical solution shows the equivalence between fluence and intensity with respect to achieving peak surface temperatures. The method helps in the optimization of laser irradiation parameters, namely, laser pulse fluence and intensity, which is especially beneficial in industrial contexts where laser parameters can be constrained by variability across different manufacturers.

Experimental and statistical investigation of the effect of input parameters on output parameters in laser cutting of stainless steel material

2025-06-17
Engin Nas , BarÄ±ĆŸ ÖZLÜ | Ironmaking & Steelmaking Processes Products and Applications
This study experimentally and statistically investigated the effects of machining parameters on surface roughness and upper and lower kerf widths during the laser cutting of AISI 304 stainless steel. The 
 This study experimentally and statistically investigated the effects of machining parameters on surface roughness and upper and lower kerf widths during the laser cutting of AISI 304 stainless steel. The experimental design was based on the L18 orthogonal array of the Taguchi technique. Laser cutting parameters included focal point (−4 mm and 4 mm), gas pressure (5, 10, and 15 bar), and cutting speed (5000, 7500, and 10,000 mm/min). The results showed that cutting speed and gas pressure reduced surface roughness up to a critical threshold. Additionally, increasing cutting speed decreased kerf widths, while higher gas pressure led to increased upper and lower kerf widths. Statistical analysis identified cutting speed as the most influential parameter for surface roughness (56.05%), upper kerf width (35.33%), and lower kerf width (66.33%). Finally, the Taguchi-based Grey relational analysis determined the optimal machining parameters as A 2 B 1 C 3 .

Laser machining of silicon carbide: current status, applications and challenges

2025-06-17
Yan Peng , Junshan Zeng , Xiaozhu Xie +2 more | Optics & Laser Technology

Laser-Drilled Microstructures for Enhanced Luminous Efficiency and Wide-Angle Emission in WLEDs

2025-06-17
Ping Wan , Chien-Wei Huang , Chun-Nien Liu +3 more | Optics Express

Non-destructive UV femtosecond laser cleaning of primer on CFRP surface

2025-06-17
Meiling Xin , Shang Li , Junyi Gu +5 more | Optics & Laser Technology

Experimental study on machinability and surface integrity of CFRP plate via magnetic field–assisted picosecond laser micromachining

2025-06-17
Ya Lu , Yingjie Xu , Peng Wang +3 more | The International Journal of Advanced Manufacturing Technology

Construction of the heterogeneous coating model and multi-physics coupling analysis in laser cleaning

2025-06-17
Zhe Li , Sijie Wang , Yaokun Pan +2 more | Optics & Laser Technology

Mechanism analysis of blasting impact mechanism in the water jet–guided laser processing for aerospace composite materials

2025-06-17
Yinuo Zhang , Xinfeng Wang , Feng Guo +5 more | The International Journal of Advanced Manufacturing Technology

Solution‐Repair‐Assisted Femtosecond Laser Crystallization of Fluoroaluminate Glass for Customized UV–Visible–Infrared Brittle Micro‐Diffractive Optics

2025-06-16
Qisong Li , H. Zhang , Huadan Zheng +2 more | Laser & Photonics Review
Abstract A novel solution‐repair‐assisted femtosecond laser crystallization method is reported for Fluoroaluminate (AlF 3 ) glass, with exceptional ultraviolet–visible‐mid‐infrared transmission characteristics, for fabricating wide‐wavelength micro‐optical elements. This innovative approach achieves 
 Abstract A novel solution‐repair‐assisted femtosecond laser crystallization method is reported for Fluoroaluminate (AlF 3 ) glass, with exceptional ultraviolet–visible‐mid‐infrared transmission characteristics, for fabricating wide‐wavelength micro‐optical elements. This innovative approach achieves remarkable optical quality through amorphous‐to‐crystalline phase transition, effectively mitigating the longstanding challenge of surface roughness in laser‐processed brittle materials. A systematic investigation is conducted into the effects of various laser parameters (e.g., laser energy, repetition rate, and scanning velocity) on the fabricated AlF 3 glass microstructure after crystallization. Leveraging these data, diverse micro‐diffractive optical elements are successfully fabricated on AlF 3 glass, including 1D and 2D gratings with tunable duty cycles, square grating, circular grating, and Dammann grating. All these elements demonstrated exceptional optical diffraction performance. Additionally, by implementing precise control of structural features, a regulated micro‐diffractive optical device with tailored structural dimensions is designed and fabricated. As a demonstration, a Fresnel zone plate (FZP) with varying widths and radii for each concentric circle is fabricated, achieving a fabrication error below 1 ”m. The focusing and imaging performance of AlF 3 glass FZP is validated across ultraviolet, visible and infrared wavelengths, showcasing its superior optical capabilities. This work establishes a new paradigm for the fabrication of wide‐wavelength brittle micro‐optical elements and opens new possibilities for multi‐spectrum photonics.

Double-Pulse Femtosecond Laser Fabrication of Highly Ordered Periodic Structures on Au Thin Films Enabling Low-Cost Plasmonic Applications

2025-06-16
Fotis Fraggelakis , Panagiotis Lingos , George D. Tsibidis +7 more | ACS Nano
Periodic plasmonic arrays, making possible excitations of surface lattice resonances (SLRs) or quasi-resonant features, are of great importance for biosensing and other applications. Fabrication of such arrays over a large 
 Periodic plasmonic arrays, making possible excitations of surface lattice resonances (SLRs) or quasi-resonant features, are of great importance for biosensing and other applications. Fabrication of such arrays over a large area is typically very costly and time-consuming when performed using conventional electron beam lithography and other methods, which reduce application prospects. Here, we propose a technique of double femtosecond pulse (∌170 fs) laser-assisted structuring of thin (∌32 nm) Au films deposited on a glass substrate and report a single-step fabrication of homogeneous and highly ordered Au-based laser-induced periodic surface structures (LIPSS) over a large area. Our experimental results unveil the key importance of the interpulse delay as the determining factor rendering possible the homogeneity of laser-induced structures and confirm that highly ordered, functional LIPSS occurs solely upon double pulse irradiation under a specific interpulse delay range. A theoretical investigation complements experimental results, providing significant insights into the structure formation mechanism. Ellipsometric measurements show that such LIPSS structures can exhibit highly valuable plasmonic features in light reflection. In particular, we observed ultranarrow resonances associated with diffraction-coupled SLRs, which are of paramount importance for biosensing and other applications. The presented data suggest that femtosecond double pulse structuring of thin metal films can serve as a valuable and low-cost tool for large-scale fabrication of highly ordered functional elements and structures.

Analysis of GFRP hybrid laser and mechanical cutting of large wind turbine blade flashing

2025-06-16
Chunmeng Chen , Long Chen , Wenyuan Li +3 more | Journal of Manufacturing Processes

Reinforcement-learning-driven spectral broadening in NPR laser: 114.3-nm bandwidth generation with sub-minute optimization

2025-06-16
Li Chen , Wen Zhong , Zhou Zhehai +7 more | Optics Letters

Mid-Infrared Laser Sources and Their Applications in Materials Processing

2025-06-16
Kenji Goya , Seiji Shimizu , Ryo Yasuhara +2 more | IntechOpen eBooks
This review focuses on recent advances in mid-infrared (MIR) laser technology in materials processing, with an emphasis on fiber Bragg gratings (FBGs) fabricated by femtosecond lasers. The plane-by-plane femtosecond writing 
 This review focuses on recent advances in mid-infrared (MIR) laser technology in materials processing, with an emphasis on fiber Bragg gratings (FBGs) fabricated by femtosecond lasers. The plane-by-plane femtosecond writing technique enables precise, highly stable FBGs directly within fluoride glass fibers, forming compact, wavelength-selective laser cavities. These advances have led to the development of high-efficiency MIR fiber lasers operating near 2.8–2.92 ÎŒm, offering strong material absorption that facilitates cutting, surface modification, and fusion splicing with minimal thermal damage. Polymer and glass materials, which often pose challenges for traditional near-infrared (NIR) lasers, can be processed more effectively with MIR sources. Although FBGs are integral to many MIR laser architectures, certain systems such as 2.92 ÎŒm Er:YAP lasers have been realized without FBGs. MIR fiber lasers present a promising platform for photonic manufacturing, addressing the growing demand for precise and efficient processing across a variety of advanced materials. Continued innovations in FBG fabrication, fiber integration techniques, and thermal management are expected to further expand the capabilities and applications of MIR laser technologies.

Evaluation and analysis of passive optical network in investigating drilling time relative to material thickness

2025-06-14
Ashok Kumar , Ashish Kumar Singh , Abhishek Kumar Yadav +2 more | Journal of Optical Communications
Abstract This study investigates the influence of key process parameters – abrasive flow rate, traverse speed, material properties, and milling depth – on reducing machining time using abrasive waterjet machining 
 Abstract This study investigates the influence of key process parameters – abrasive flow rate, traverse speed, material properties, and milling depth – on reducing machining time using abrasive waterjet machining (AWJM). A modified abrasive feed system was developed to explore the effects of mass flow rate changes on traverse speed and machining efficiency, revealing traverse speed as a critical factor in Controlled Depth Milling (CDM). Materials such as brass, AL 2024, AL 6061, AISI 304, titanium, and tool steel were tested, with findings showing that increased traverse speed reduces surface waviness. A novel “Machinability Index” was proposed to assess how material type affects milling time, with low-machinability materials requiring slower speeds. Surface roughness was predicted using a model based on solid particle erosion and jet penetration, which aligned well with experimental results. The study also examined abrasive waterjet trepanning for aerospace materials, analyzing parameters like pressure and traverse speed using a full factorial design. Empirical models were developed to understand their effects on kerf width, surface texture, and hole roundness. The research highlights the potential of integrating optical communication systems for real-time process monitoring and automation, enhancing precision and efficiency in advanced manufacturing environments.

Precision cutting of the ABS film by ultraviolet picosecond laser

2025-06-13
Zhenhua Gao , Tao Deng , Congyi Wu +3 more | Optics & Laser Technology

The laser-induced damage-growth threshold at 351 nm in the nanosecond regime in dielectric coatings employing different high-index materials

2025-06-13
Marek StehlĂ­k , Alexei A. Kozlov , Kyle R. P. Kafka +4 more | Optics Letters

Study on the laser ablation behavior of carbon fiber reinforced polymer laminates under the air environment

2025-06-12
Weina Zhao , Dongfang Zheng | Research Square (Research Square)
<title>Abstract</title> During laser irradiation, carbon fiber reinforced polymer ( CFRP ) will undergo complex damage behavior. How to characterize its ablation behaviors under the air environment is of great significance 
 <title>Abstract</title> During laser irradiation, carbon fiber reinforced polymer ( CFRP ) will undergo complex damage behavior. How to characterize its ablation behaviors under the air environment is of great significance to the thermal protection design of aerospace structures. However, current models lack the capability to accurately simulate the multi-parameter ablation behavior and failure mechanisms under combined laser-airflow effects. Firstly, considering ablation mechanisms of matrix pyrolysis, carbon fiber oxidation and sublimation a thermo-mechanical coupling model was constructed to obtain the temperature-dependent thermophysical and mechanical properties. Secondly, a numerical simulation method based on the Arbitrary Lagrangian-Eulerian (ALE) adaptive mesh and the traditional ablation kinetics is developed. Lastly, compared with the experimental results, this work elucidates the relative contributions of different ablation mechanisms of CFRP laminates and systematically predicts their laser ablation progression under the graded power density conditions. Coupled thermal-mechanical analysis model reveals that the contribution of each ablative mechanisms is distinctive at the different laser power densities of the laser ablation pit.

Mechanism-based and parameter-selected composite laser complete cleaning for aircraft skin

2025-06-12
Tengfei Li , Zhenzhou Wang , Jinghua Han +4 more | Journal of Physics D Applied Physics
Abstract Abstract: In this study, aircraft skin cleaning using a "continuous + pulse mode" composite laser was investigated. The mechanism and optimum parameters of the composite laser cleaning mechanism were 
 Abstract Abstract: In this study, aircraft skin cleaning using a "continuous + pulse mode" composite laser was investigated. The mechanism and optimum parameters of the composite laser cleaning mechanism were studied experimentally, theoretically and via thermodynamic simulation. In a composite laser system, a continuous laser is used to achieve fast and efficient cleaning; however, the ablative residue may easily adhere to the substrate and form a residue. The ablative impact of a nanosecond-pulsed laser can effectively remove high-temperature ablative residues in a short time. Thus, herein, a composite laser ablation model was established, and the influence of laser parameters on cleaning quality and efficiency was studied. By optimizing and controlling the laser parameters, an efficient scanning and non-destructive cleaning of aircraft skin was realised.

Characterization of ultra-intense laser focal spot parameters based on laser accelerated electrons

2025-06-10
Bo Xie | Applied Physics B