Nearly perfect resonant absorption and coherent thermal emission by hBN-based photonic crystals
Date
2017Source Title
Optics Express
Print ISSN
1094-4087
Publisher
Optical Society of America
Volume
25
Issue
25
Pages
31970 - 31987
Language
English
Type
ArticleItem Usage Stats
250
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219
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Abstract
In this paper, we numerically demonstrate mid-IR nearly perfect resonant absorption and coherent thermal emission for both polarizations and wide angular region using multilayer designs of unpatterned films of hexagonal boron nitride (hBN). In these optimized structures, the films of hBN are transferred onto a Ge spacer layer on top of a one-dimensional photonic crystal (1D PC) composed of alternating layers of KBr and Ge. According to the perfect agreements between our analytical and numerical results, we discover that the mentioned optical characteristic of the hBN-based 1D PCs is due to a strong coupling between localized photonic modes supported by the PC and the phononic modes of hBN films. These coupled modes are referred as Tamm phonons. Moreover, our findings prove that the resonant absorptions can be red- or blue-shifted by changing the thickness of hBN and the spacer layer. The obtained results in this paper are beneficial for designing coherent thermal sources, light absorbers, and sensors operating within 6.2 μm to 7.3 μm in a wide angular range and both polarizations. The planar and lithography free nature of this multilayer design is a prominent factor that makes it a large scale compatible design. © 2017 Optical Society of America.
Keywords
AbsorptionPhotonic crystals
Surface waves
Surface plasmon polaritons
Surface plasmons
Thermal emission
Microcomputers
Multilayer films
Multilayers
Polarization
Alternating layers
Coherent thermal emission
Hexagonal boron nitride (h-BN)
Multilayer designs
One-dimensional photonic crystal (1D PC)
Optical characteristics
Optimized structures
Resonant absorption
Potassium compounds