摘要
This work both numerically and experimentally investigates hemispherical radiative properties (absorptance, reflectance, and transmittance) of complex gratings. Crystal silicon is employed to generate samples. One is a double-sided polished 520-μm-thick substrate, and the other is a substrate with complex gratings on its top. The incidence wavelength λ ranges from 0.5 μm to 1.7 μm, containing the intrinsic band gap wavelength λ <sub>bg</sub> = 1.09 μm. Wavelength-selective and polarization-sensitive features are exhibited in spectra of properties for complex gratings. The wavelength-selectivity and polarization-sensitivity are elaborated using near-field electromagnetic patterns at three representative wavelengths (λ < λ <sub>bg</sub> , λ ≈ λ <sub>bg</sub> , and λ > λ <sub>bg</sub> ).