2021/08/19 by Sahoo, Nihar Ranjan, Dixit, Saurabh, Singh, Anuj Kumar +3
#Applied Physics (physics.app-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Optics (physics.optics)
paper · doi:10.48550/arxiv.2108.08510
Integration of conventional mid to long-wavelength infrared polarizers with chip-scale platforms is restricted by their bulky size and complex fabrication. Van der Waals materials based polarizer can address these challenges due to its non-lithographic fabrication, ease of integration with chip-scale platforms, and room temperature operation. In the present work, mid-IR optical response of the sub-wavelength thin films of α-MoO3 is investigated for application towards high temperature mid-IR transmission and reflection type thin film polarizer. To our knowledge, this is the first report of above room temperature mid-IR optical response of α-MoO3 to determine the thermal stability of the proposed device. We find that our α-MoO3 based polarizer retains high extinction ratio with peak value exceeding 10 dB, up to a temperature of 140∘C. We explain our experimental findings by natural in-plane hyperbolic anisotropy of α-MoO3 in the mid-IR, high temperature X-ray diffraction and Raman spectroscopic measurements. This work opens up new avenues for naturally in-plane hyperbolic van der Waals thin-films to realize sub-wavelength IR optical components without lithographic constraints.