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

Abstract

Infrared gradient refractive index (GRIN) lenses have great application value and potential in multispectral imaging systems. This study reports various chalcogenide axial GRIN glasses prepared using the hot‐pressing diffusion method. It is worth noting that the S4–S60 GRIN sample has a difference in refractive index (RI) Δn of greater than 0.3 and a diffusion depth of about 5 mm, which is the deepest diffusion depth reported in chalcogenide glass to date. In addition, the linear portion in the profile of the GRIN sample has a RI difference of 0.15 and a thickness of 1.2 mm. The effects of the temperature, concentration difference, and diffusion time on the sample diffusion process are discussed. The dispersion properties of the GRIN samples were further calculated, providing a new option for correcting chromatic aberrations in optical systems. In addition, a method for the indirect nondestructive characterization of sample RI using the Raman intensity ratio is proposed, and the reliability of the method is verified by practical experiments, which is convenient for the subsequent measurement of the GRIN profile.

Customized linear refractive index GRIN prepared by rapid sintering of multilayer chalcogenide glass powders

“…Liu Zijun et al prepared GRIN samples with refractive index difference (Δn) greater than 0.3 and diffusion depth of about 5 mm by thermal diffusion. 14 In this case, the refractive index gradient comes from elemental diffusion between the glass layers, which is driven by thermal energy and concentration differences. In general, the diffusion of multiple thin glass layers allows for more controlled changes in the refractive index of the GRIN.…”

Research on gradient refractive index (GRIN) rod lens by three-step ion exchange processes

“…GRIN element is a kind of micro optical element that realizes its optical function by changing the refractive index without changing the surface profile [1][2][3][4] . They have been fabricated in glass, plastic, crystals, and recently infraredtransmitting glass ceramics, using many different techniques, including ion exchange [5], chemical vapor deposition [6], sol-gel processing [ 7] , copolymer diffusion [8] , nanolayered coextrusion [9], layered diffusion [10], molded fusion [11] , and so on. Sol-gel processing has demonstrated many successes in fabricating radial gradient-index profiles.…”