100-kHz diffraction-limited femtosecond laser micromachining

We demonstrate active and adaptive wavefront correction of a 100-kHz amplified femtosecond laser chain, and investigate the subsequent improvement for micromachining applications. Thanks to a non-pixelated liquid-crystal modulator, phase-front distortions are decreased down to lambda/15 peak-valley and lambda/100 rms. Clean 1.7-mum diffraction-limited microholes are obtained, both on low-threshold metallic and high-threshold dielectric materials. This high beam quality femtosecond source enables diffraction-limited high-speed micromachining.