Improved selectivity of optical transmission through cascaded waveguide-metal-grating filters

TL;DR

This paper analyzes cascaded waveguide-metal-grating filters, demonstrating enhanced optical transmission selectivity and efficiency, with potential applications in infrared detection due to their compact size and good angular tolerance.

Contribution

It introduces a novel analysis of cascaded metallic grating filters showing improved selectivity beyond simple convolution of individual responses.

Findings

Enhanced resonant transmission efficiency

Good angular tolerance maintained

Potential for infrared detection applications

Abstract

The resonant transmission of two near-field coupled, cascaded band-pass filters, based on metallic stripe or patch gratings, is analysed. The response, in terms both of maximum efficiency and light rejection out of the resonance, overpasses the simple convolution of the responses of two isolated filters, while keeping good angular tolerance. Illustrations are given in the infrared range where sizing and technological integration of such compact structures are particularly relevant for detection applications.