Ultra-broadband strong absorption over 92% covering the infrared wavelength range of 1 ~ 6μm is demonstrated by using the tapered hyperbolic Au-SiO2 multilayer waveguides on glass substrates. Such broadband absorption is formed by the stop-light modes at various wavelengths located at different waveguide widths. A planar hyperbolic waveguide model is built to determine the stop-light modes by considering both forward and backward guided modes. The stop-light modes located inside the Au-SiO2 multilayer waveguide are simulated at the absorption peaks by reducing the Au loss. Tapered multilayer waveguides with varying top widths are further simulated, fabricated and measured, indicating the almost linear relation between the waveguide width and the stop-light wavelength. Moreover, the broadband absorption of tapered waveguide is proved to be angle-insensitive and polarization-independent, and the heat generation and temperature increase are also discussed.
H. Deng et al., "Ultra-Broadband Infrared Absorption by Tapered Hyperbolic Multilayer Waveguides," Optics Express, vol. 26, no. 5, pp. 6360-6370, Optical Society of America (OSA), Mar 2018.
The definitive version is available at https://doi.org/10.1364/OE.26.006360
Mechanical and Aerospace Engineering
Keywords and Phrases
Gold compounds; Light absorption; Multilayers; Silica; Substrates; Ultra-wideband (UWB); Broadband absorption; Forward-and-backward; Hyperbolic waveguides; Infrared wavelengths; Multilayer waveguides; Polarization independent; Strong absorptions; Temperature increase; Waveguides
International Standard Serial Number (ISSN)
Article - Journal
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