Broad‐Spectral‐Range Sustainability and Controllable Excitation of Hyperbolic Phonon Polaritons in α‐MoO<sub>3</sub>
Broad‐Spectral‐Range Sustainability and Controllable Excitation of Hyperbolic Phonon Polaritons in α‐MoO<sub>3</sub>
Hyperbolic phonon polaritons (HPhPs) in orthorhombic-phase molybdenum trioxide ($\alpha$-MoO3) show in-plane hyperbolicity, great wavelength compression and ultra-long lifetime, therefore holding great potential in nanophotonic applications. However, its polaritonic response in the far-infrared (FIR) range has long remained unexplored due to challenges in experimental characterization. Here, using monochromated electron energy loss …