High-efficiency visible and near-infrared transmission gratings in fused silica for astronomical ground-based telescope spectrographs

We report on high-efficiency visible and near-infrared transmission gratings in fused silica generated by holographic recording and reactive ion beam etching technology. At a wavelength of 740 nm, near 100% diffraction efficiency is achieved under Littrow conditions. The design is based on the phenomenon of the high aspect ratio gratings by using the rigorous coupled wave analysis. A binary grating with the optimum grating period of 740 nm and groove depth of 1.55 had been fabricated in the paper. The grating wavelength bandwidth and angular bandwidth are extremely enhanced compared with conventional volume phase holographic gratings, making these gratings the key elements in high-resolution astronomical ground-based telescope spectrographs.