Spectral and angular shaping of infrared radiation in a polymer resonator with molecular vibrational modes

Shinichiro Tsuda, Shuhei Yamaguchi, Yoshiaki Kanamori, Hiroo Yugami

研究成果: Article査読

17 被引用数 (Scopus)

抄録

We present a comprehensive approach for tailoring the spectral and angular properties of infrared thermal radiation by using a polymer resonator with molecular vibrational modes, consisting of a polymer thin film on a back-reflective substrate. To precisely design the resonator, we derived the infrared dielectric function of a poly(methyl methacrylate) (PMMA) thin film from the measured reflectance spectrum by fitting it with a Gaussian-convoluted Drude-Lorentz model while accounting for the inhomogeneous broadening caused by the disordered structure of polymers. Our experimental and numerical characterization confirms that the polymer resonator exhibits spectral shaping from quasi-broadband to narrowband due to the intrinsic molecular vibrational absorption of the polymer. The frequency-isolated and strong molecular vibrational absorption of the carbonyl stretching mode at 1730 cm−1 enables the narrowband shaping of the PMMA resonator. In addition, we confirm that the angular-shaping characteristics of this polymer resonator can be tuned, from omnidirectional to strongly angular selective, by changing its polymer film thickness. Modal dispersion analysis reveals that the angle-selectivity of the polymer resonator at an angle of incidence of 80° comes from coupling between the molecular vibrational mode and leaky mode. The proposed infrared radiation management strategy based on molecular vibrational modes of polymers is cost-effective, scalable, and works well with terrestrial matter, including organic compounds and gas molecules, showing promise for applications such as optical gas sensing and radiative thermal management.

本文言語English
ページ(範囲)6899-6915
ページ数17
ジャーナルOptics Express
26
6
DOI
出版ステータスPublished - 2018

ASJC Scopus subject areas

  • 原子分子物理学および光学

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