Diffusion-based gradient index optics for infrared imaging

Abstract

New moldable, infrared (IR) transmitting glasses and diffusion-based gradient index (GRIN) optical glasses enable simultaneous imaging across multiple wavebands including shortwave infrared, midwave infrared, and long-wave infrared, and offer potential for both weight savings and increased performance in optical sensors. Lens designs show potential for significant reduction in size and weight and improved performance using these materials in homogeneous and GRIN lens elements in multiband sensors. An IR-GRIN lens with Δn ¼ 0.2 is demonstrated. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Femtosecond Laser Direct Writing of Gradient Index Fresnel Lens in GeS2-Based Chalcogenide Glass for Imaging Applications

“…GRIN optics involve creating a spatial variation of the refractive index in the material. In its primary use, this index variation can correct some optical aberrations such as spherical aberration [4] and chromatic aberrations [5][6][7], or can encode optical power inside the lens (not simply at the surface) [8,9].…”

“…More specifically, chalcogenide materials have the advantage of exhibiting a very wide transmission band which can, for some specific compositions, span the visible and LWIR windows. These glass materials are increasingly being used in the field of infrared optical imaging [6] for their excellent optical qualities but remain infrequently studied in integrated optical component manufacturing, particularly with the FLDW technique.…”

Preparation and refractive index characterization of chalcogenide glasses with gradient refractive index

“…However, the development of meta‐surface lenses still faces some challenges, 4 especially in the field of long‐wave infrared. Although infrared GRIN lenses also face many problems, they can be directly replaced by lenses in existing optical systems to reduce the lens volume after successful preparation 5 …”

“…Several schemes have been attempted in the IR field with stunning results, such as ion exchange, 10 glass–ceramics, 16,21 and thermal diffusion 5,22 . Fourmentin et al.…”

“…Although infrared GRIN lenses also face many problems, they can be directly replaced by lenses in existing optical systems to reduce the lens volume after successful preparation. 5 Polymers, [6][7][8] glass, 1,2,9,10 ceramic materials, 11 and glassceramic composites [12][13][14][15] can be considered for GRIN component fabrication. However, material options in the infrared range are extremely limited, particularly those with high transmittance properties above 2 µm.…”