Grayscale Electron Beam Lithography Direct Patterned Antimony Sulfide

TL;DR

This paper introduces a novel method combining grayscale electron beam lithography and direct forming to create three-dimensional antimony sulfide structures with applications in micro/nanooptics and lab-on-chip devices.

Contribution

It is the first demonstration of fabricating free-form antimony sulfide structures using this combined lithography and forming approach.

Findings

Successfully fabricated 4-level Fresnel Zone Plates and metalenses.

Optimized the refractive index using an algorithm combining genetic algorithm and transfer matrix method.

Enabled single-step fabrication of 3D diffractive optical elements and metasurfaces.

Abstract

The rise of micro/nanooptics and lab-on-chip devices demands the fabrication of three-dimensional structures with decent resolution. Here, we demonstrate the combination of grayscale electron beam lithography and direct forming methodology to fabricate antimony sulfide structures with free form for the first time. The refractive index of the electron beam patterned structure was calculated based on an optimization algorithm that is combined with genetic algorithm and transfer matrix method. By adopting electron irradiation with variable doses, 4-level Fresnel Zone Plates and metalens were produced and characterized. This method can be used for the fabrication of three-dimensional diffractive optical elements and metasurfaces in a single step manner.