Guided-mode resonance with reduced bandwidth in mid-infrared absorption and thermal emission

Abstract

Narrowband resonance plays an important role in many optical applications, especially for the development of wavelength-selective properties and enhanced light–matter interaction. In this paper, we demonstrate metal–insulator–metal (MIM) waveguide gratings, which exhibit guided-mode resonance (GMR) with reduced bandwidth in mid-infrared absorption and thermal emission. Our fabricated MIM waveguide grating consists of a copper substrate, a lossless ZnSe film, and a top gold stripe grating. Our measurements reveal strong GMRs with a bandwidth of 1.29% of the central wavelength in both mid-infrared absorption and thermal emission spectra. By varying structural parameters of the MIM waveguide grating, strong absorptions and thermal emissions of GMRs are observed and tuned within the 3–5 µm wavelength range. These results manifest the great potential of engineering infrared properties by using GMR and could be useful for spectral control in a variety of infrared devices.