Polarization-Sensitive Deep-Groove Absorption Grating Based on Silicon

Abstract

The paper proposes a deep-groove grating structure that exhibits high absorption characteristics of polarized light in the near-infrared band, as revealed by analyzing the electromagnetic field of this structure. By optimizing parameters such as the period and surface structure dimensions of its unit cell, a high-quality polarization-sensitive grating absorber is obtained. Traditional silicon is limited by a bandgap of 1.12 eV, resulting in poor absorption in the near-infrared band beyond 1000 nm. The deep-groove grating structure designed in this paper overcomes the absorption limitations of silicon itself, successfully extending the upper wavelength limit of the high absorption region to 1500 nm, while also exhibiting polarization-sensitive chara-cteristics.