Stacked Wafer Gradient Index Silicon Optics with Integral Anti-reflection Layers

TL;DR

This paper presents the design and fabrication of multi-layer textured silicon AR coatings for wide bandwidth millimeter-wave applications, demonstrating high transmission from 75 to 330 GHz.

Contribution

It introduces a novel fabrication process for multi-layer textured silicon AR coatings optimized for 250 GHz, with experimental validation across a broad frequency range.

Findings

High transmission efficiency achieved between 75 and 330 GHz.

Successful fabrication of multi-layer textured silicon surfaces using DRIE.

Experimental results closely match simulation predictions.

Abstract

Silicon optics with wide bandwidth anti-reflection (AR) coatings, made of multi-layer textured silicon surfaces, are developed for millimeter and submillimeter wavelengths. Single and double layer AR coatings were designed for an optimal transmission centered on 250 GHz, and fabricated using the DRIE (Deep Reaction Ion Etching) technique. Tests of high resistivity silicon wafers with single-layer coatings between 75 GHz and 330 GHz are presented and compared with the simulations.