Fabrication of high-refractive-index glass micron-sized solid immersion lenses by a surface-tension mold technique

A surface-tension mold technique that makes use of the wetting properties between glass melt and a substrate is used to fabricate micrometer-sized solid immersion lens from a high-refractive-index glass. Solid immersion lens can be used to overcome the optical diffraction limit. In this study, glass particles made from two different glasses (n = 1.718 and 1.786) were melted on glassy-carbon substrates having optical-grade surfaces and cooled to room temperature. The optimum conditions for producing a super-spherical shape (i.e., a truncated sphere) while avoiding the crystallization of glass were obtained. The produced glass particles exhibited high transparency and super-spherical shape with smooth surfaces. The variations in the lens thickness and sphericity are submicron or less. Optical lens systems specially designed for these super-spherical lenses are expected to be capable of achieving resolutions that are 2.0 times higher than those attainable with conventional optical systems. (c) 2007 Elsevier B.V. All rights reserved.