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

Sina Abedini Dereshgi, Thomas G. Folland, Akshay A. Murthy, Xianglian Song, Ibrahim Tanriover, Vinayak P. Dravid, Joshua D. Caldwell, Koray Aydin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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, α-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 α-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 α-MoO3 is reported without the need for nanoscale fabrication on the α-MoO3. We observe coupling between the α-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.

Original languageEnglish (US)
Article number5771
JournalNature communications
Volume11
Issue number1
DOIs
StatePublished - Dec 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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