Generation of optical quality structured surfaces on borosilicate glass using 515nm picosecond laser pulses and a liquid-crystal-based spatial light modulator

摘要

Liquid-crystal-based spatial light modulators (LC-SLMs) are electrically programmable devices which allow us to modulate the phase and amplitude of the linear-polarised light. The high spatial resolution of LC-SLMs (typically more than 0.5 megapixels) coupled with their relatively high optical damage threshold and ease of programming mean that these devices have started to be used with commercially-available short-pulsed lasers to generate complex beam shapes for parallel processing of bulk metals and thin metal films.This poster presents work in which a LC-SLM operating in the visible spectral region is used for shaping the surface of optical glass (Borofloat®33 from Schott AG). The aim of this research is to produce structures with the optical quality on the glass surface, so that they can be used, for instance, as optical components. In this work, picosecond laser pulses at λ = 515nm are delivered to the SLM display in order to produce surface deformations whose contour corresponds to the SLM-generated image. Since glass is normally transparent at the wavelength of 515nm, the workpiece is coated with a thin layer of graphite prior to laser treatment in order to enhance laser-beam interaction with this material and obtain localised melting of its surface.