1. Coupled surface plasmon–phonon polariton nanocavity arrays for enhanced mid-infrared absorption
- Author
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Kachiraju Satya R., Nekrashevich Ivan, Ahmad Imtiaz, Farooq Hira, Chang Long, Kim Sangsik, and Kim Myoung-Hwan
- Subjects
coupled plasmon–phonon polariton mode ,enhanced optical power absorption ,fabry–pérot cavity array ,propagating surface phonon polaritons ,Physics ,QC1-999 - Abstract
Resonant optical cavities are essential components in mid-infrared applications. However, typical film-type cavities require multilayer stacks with a micron-thick spacer due to mid-infrared wavelengths, and their performance is limited by narrow frequency tunability and angular sensitivity. We propose and experimentally demonstrate the subwavelength-scale (≈λ0/150) resonant nanocavity arrays that enhance the absorption spectrum of the device in the mid-infrared (10–12 microns) via excitation of coupled surface plasmon–phonon polaritons. The proposed metal–insulator–polar dielectric (gold–silicon–silicon carbide) structure supports a guided mode of the coupled surface polaritons in the lateral direction while vertically confining the mid-infrared wave within the 80 nm thick dielectric spacer. In particular, the subwavelength-scale (≈λ0/10) gratings are imposed to form Fabry–Pérot cavity arrays displaying angle-insensitive and frequency-tunable absorption of up to 80% of the optical power in the mid-infrared. Our work should benefit diverse mid-infrared applications and novel designs of polariton-based photonic devices.
- Published
- 2022
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