Advanced modelling of a moderate-resolution holographic spectrograph

TL;DR

This paper presents an accurate optical modeling approach for a holographic spectrograph with cascaded volume-phase holographic gratings, achieving high spectral resolution and throughput with minimal cross-talks.

Contribution

It introduces a combined analytical and numerical modeling method for optimizing a cascade holographic spectrograph design, addressing cross-talk and stray light issues.

Findings

High throughput up to 53% achieved.

No significant cross-talks or ghost images detected.

Effective modeling approach for spectrograph optimization.

Abstract

In the present article we consider an accurate modeling of spectrograph with cascade of volume-phase holographic gratings. The proposed optical scheme allows to detect spectra in an extended wavelength range without gaps providing relatively high spectral resolution and high throughput. However, modeling and minimization of possible cross-talks between gratings and stray light in such a scheme represents a separate task. We use analytical equations of coupled wave theory together with rigorous coupled wave analysis to optimize the gratings parameters and further apply the latter together with non-sequential raytracing algorithm to model propagation of beams through the spectrograph. The results show relatively high throughput up to 53% and absence of any significant cross-talks or ghost images even for ordinary holograms recorded on dichromated gelatin.