Polarization-independent broad-band nearly perfect absorbers in the visible regime.
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.
Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan.
Chia-Hung
CH
Lin
Ruey-Lin
RL
Chern
Hoang-Yan
HY
Lin
D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation*