Holographic femtosecond laser processing using 6.3 kHz pulse-to-pulse spatial light modulation with binary phase masks

Abstract

Femtosecond laser pulses were spatially modulated with fast reconfiguration of computer-generated holograms (CGHs) using a ferroelectric liquid-crystal-on-silicon spatial light modulator (FLCoS-SLM). Reconfiguration was executed at a frame rate of more than 1 kHz while changing the CGH every frame. The CGHs were designed as binary phases because the FLCoS-SLM can represent only binary values. The optimization method was modified by the weighted iterative Fourier transform algorithm (IFTA) to make the binary phase. The fundamental performance of the CGH reconstruction and femtosecond laser processing with 6.3 kHz pulse-to-pulse spatial light modulation was demonstrated. The reconfiguration speed will drastically change the applicability to science and industrial fields and open a door for new CGH applications.