Low-Symmetry Polaritonic Materials for Infrared Polarization Control

Two-dimensional layered materials have recently garnered burgeoning amount of interest due to their unique electronic, optical, thermal, mechanical properties emerging at the mono-to-few layer thicknesses. Most of research has focused on conventional 2D materials such as graphene and 2D TMDCs, having isotropic electronic and optical properties due to their crystal symmetry. Recently, layered materials such as black phosphorus and hexagonal boron nitride investigated for anisotropic crystal structure. In this talk, I will introduce α-MoO₃ as an anisotropic photonic and polaritonic material. α-MoO₃ is a layered material that exhibits both in and out-of-the-plane anisotropic polaritonic response at mid-IR wavelengths. We designed and experimentally demonstrated an anisotropic polaritonic absorber and showed that one can couple to all phonon modes and address them individually either using structural tunability or polarization control of incident infrared radiation. Moreover, I will introduce MOCVD grown β-Ga₂O3 as an emerging material for IR photonics applications due to its anisotropic crystal symmetry. Detailed numerical modelling and experimental characterizations highlighting unique IR properties for manipulating and controlling the polarization response will be discussed.