Broadband Internal Reflection Super‐Wavelength Immersion Gratings With Deep‐Layers Structure via Imprint Replication Technology for Hyperspectral Imaging

ABSTRACT Immersion gratings, a combination of reflective grating layers and a prism, enable spectrometers to achieve high dispersion and throughput. However, existing immersion gratings still face limitations in terms of operating bandwidth and preparation costs. Here, we propose a broadband internally reflective super‐wavelength immersion grating (SWIG) with a deep‐layer structure, which operates over a 400–1000 nm wavelength range. The SWIG shows several advantages throughout the operating band: first, unpolarized efficiencies exceeding 44.7% (up to 85%); second, polarization sensitivity suppression within 9%; third, incidence angle tolerance greater than 20°; and fourth, good dispersion uniformity. In addition, we demonstrate in detail a low‐cost fabrication scheme for SWIGs using imprint replication techniques. Optical measurements of the SWIG samples show good agreement with theoretical calculations, proving the feasibility of the fabrication scheme. This work provides strong support for promoting the wide application of high‐performance and low‐cost grating components in hyperspectral cameras.