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Lithography-free IR polarization converters via orthogonal in-plane phonons in a-MoO3 flakes
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Lithography-free IR polarization converters via orthogonal in-plane phonons in a-MoO3 flakes

Sina Abedini Dereshgi, Thomas G Folland, Akshay A Murthy, Xianglian Song, Ibrahim Tanriover, Vinayak P Dravid, Joshua D Caldwell and Koray Aydin
ArXiv.org
06/18/2020
DOI: 10.48550/arxiv.2006.10855
url
https://doi.org/10.48550/arxiv.2006.10855View
Preprint (Author's original)This preprint has not been evaluated by subject experts through peer review. Preprints may undergo extensive changes and/or become peer-reviewed journal articles. Open Access

Abstract

Exploiting polaritons in natural vdW materials has been successful in achieving extreme light confinement and low-loss optical devices and enabling simplified device integration. Recently, a-MoO3 has been reported as a semiconducting biaxial vdW material capable of sustaining naturally orthogonal in-plane phonon polariton modes in IR. In this study, we investigate the polarization-dependent optical characteristics of cavities formed using a-MoO3 to extend the degrees of freedom in the design of IR photonic components exploiting the in-plane anisotropy of this material. Polarization-dependent absorption over 80% in a multilayer Fabry-Perot structure with a-MoO3 is reported without the need for nanoscale fabrication on the a-MoO3. We observe coupling between the a-MoO3 optical phonons and the Fabry-Perot cavity resonances. Using cross-polarized reflectance spectroscopy we show that the strong birefringence results in 15% of the total power converted into the orthogonal polarization with respect to incident wave. These findings can open new avenues in the quest for polarization filters and low-loss, integrated planar IR photonics and in dictating polarization control.
Physics - Optics

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