X.D. Jiang

Fabrication of concave microlens arrays by local fictive temperature modification of fused silica

A simple and convenient means of fabricating concave microlens arrays direct on silica glass by using the local fictive temperature modification of fused silica is presented. This method is based on the fact that an increased fictive temperature results in a much higher HF acid etching rate of fused silica. Combining the abrupt local fictive temperature enhancement by the CO2 laser pulse and the subsequent etching by the HF acid solution, concave microlens arrays with high fill factors, excellent smoothness, and optical performance are generated on fused silica.

Optical modulation study of repaired damage morphologies of fused silica by scalar diffraction theory

Abstract. The cone and Gaussian repaired damage craters are two typical morphologies induced by CO2 laser evaporation and nonevaporation technologies. The mathematical models are built for these two types of repaired craters, and the light modulation at 355 nm induced by the millimeter-scale repaired damage morphology is studied by scalar diffraction theory. The results show that the modulation of the Gaussian repaired morphology has one peak and then decreases with the increasing distance from 0 to 30 cm. While the modulation for cone repaired morphology remains stable after decreasing quickly with the increasing distance. When the horizontal radius increases, the modulation looks like a saw-tooth. However, the modulation has irregular variations for two kinds of morphologies with the increasing vertical depth. The simulated results agree well with experimental results. The horizontal and vertical dimensions, and downstream distance have different influences on the modulation. The risk of damage to downstream optical components can be suppressed to improve the stability of the optical system if the shape and size of repaired craters are well controlled and the positions of downstream optical components are selected appropriately.