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Updated: Jun 5, 2026

Characterization of Biological Absorption Spectra Spanning the Visible to the Short-Wave Infrared
Published on: January 10, 2025
Polarization-independent broad-band nearly perfect absorbers in the visible regime
Chia-Hung Lin1, Ruey-Lin Chern, Hoang-Yan Lin
1Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan.
Abstract:
Polarization-independent broad-band absorbers in the visible regime are theoretically investigated. The absorbers are three-layered structures consisting of a lossy dielectric grating on top of a low-loss dielectric layer and a substrate of the same lossy dielectric placed at the bottom. Enhanced absorption in the underlying structure is attained over a broad range of frequency for both TE and TM polarizations. In particular, a nearly perfect absorbance (over 99.6%) is achieved at λ ≈ 600 nm, around which the absorption spectra show a substantial overlap between two polarizations. The enhanced absorption is attributed to cavity resonance and its hybridization with a weakly bound surface wave. This feature is illustrated with the electric field patterns and time-averaged power loss density associated with the resonances.
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