Large-scale As-Sb-S chalcogenide glasses with ultrahigh gradient refractive index

Abstract

Gradient refractive index (GRIN) infrared lens provided additional degrees of freedom for correcting chromatic and spherical aberrations in optical design by combining an internally customized refractive index distribution with the surface curvature of optical elements. However, high-performance GRIN infrared lenses are still faced with multiple bottlenecks including complex processing processes, limited fabrication size, unsatisfying refractive index difference and inferior interface quality, which restrict their wide applications. In this study, a group of novel infrared lens with high plasticity and large refractive index difference were developed based on the As_40-xSb_xS₆₀ system. Planar and spherical infrared GRIN lenses were successfully fabricated using precision molding technology, with a maximum refractive index difference (Δn) of 0.33 at a wavelength of 2 μm. In addition, a maximum diffusion depth of 6000 μm between two pieces of glass was achieved using a high-temperature melt diffusion process. The successful preparation of large-scale Δn GRIN optical lens with controllable size and shape provides a new solution for realizing high performance and lightweight infrared optical systems.