High dispersive and monolithic 100% efficiency grisms

TL;DR

This paper introduces a monolithic fused silica grism with high angular dispersion and nearly 100% efficiency in the -1st diffraction order, achieved without metallic layers and with minimized reflection losses.

Contribution

The authors develop a single-material, high-efficiency grism with reduced diffraction orders and enhanced transmission, fabricated from fused silica, and demonstrate its performance with over 99% efficiency.

Findings

Achieved over 99% diffraction efficiency in the -1st order.

Realized a grism with 95% overall efficiency at a specific wavelength.

Reduced backside reflection using a statistical antireflective structure.

Abstract

We present a type of grism, a series combination of transmission grating and prism, in which we reduce the number of diffraction orders and achieve a configuration with very high angular dispersion. The grism can be fabricated from a single dielectric material and requires no metallic or dielectric film layers for high transmission diffraction efficiency. One can reach 100% in the -1st transmission diffraction order and the equal damage threshold as the dielectric bulk material. We realized such an element in fused silica with an efficiency of more then 99%. The bevel backside reflection is reduced by a statistical antireflective structure, so we measured an efficiency of the entire grism of 95% at a single wavelength.