Shaping the surface of Borofloat 33 glass with ultrashort laser pulses and a spatial light modulator

Appl Opt. 2014 Mar 20;53(9):1759-65. doi: 10.1364/AO.53.001759.

Abstract

We demonstrate an application of a liquid-crystal-based spatial light modulator (LC-SLM) for the parallel generation of optically smooth structured surfaces on Borofloat 33 glass. In this work, the picosecond laser beam intensity profile of wavelength 515 nm is spatially altered by a LC-SLM, and then delivered to the workpiece in order to generate surface deformations whose shape corresponds to the image generated by the LC display. To ensure that localized melting occurs without ablation, the glass surface is covered by a thin layer of graphite prior to laser treatment to provide increased linear absorption of the laser light. After laser treatment the residual graphite layer is removed using methanol and the whole sample is annealed for 1 h at a temperature of 560 °C, making the laser-induced surface deformations optically smooth.