Ultrafast laser processing with optimized wavefront modulation by liquid crystral based spatial light modulators

Abstract

Spatial beam shaping can be achieved using wavefront modulators to increase ultrafast laser processing efficiency. These modulators can display a pre-calculated phase mask on the beam path in order to shape the laser intensity distribution following a user defined target in the processing plane or volume. Due to the non-perfect optical response of wavefront modulators, the experimental distribution may differ from the target. We investigate the use of electrically addressed and optically addressed liquid crystal spatial light modulators with ultrafast laser pulses. Applications in parallelized surface and bulk processing are achieved with both modulators showing the advantages and drawbacks of these technologies. In particular, we focus on the limitations of these devices in terms of spatial and phase delay resolution, showing the consequences on the shaped beam distribution. Calculation strategies to overcome these limitations are discussed.