Femtosecond laser milling of ultrathin films of LiNbO3

Abstract

We report femtosecond laser cutting of ultrathin ferroelectric sheets. This process enables one to do rapid patterning of microns-thick films of complex oxides such as LiNbO3, which are obtained via ion-beam exfoliation from standard wafers. Cutting these fragile samples is extremely difficult using standard methods but can be done effectively with ultrafast lasers. To achieve fast writing speed, we employ a high-repetition-rate amplified Ti:sapphire laser system with a pulse peak power of ~100MW. Optimization of the depth and quality of cut were determined as a function of laser pulse energy, crystallographic axes, optical polarization, and pre- and post-ablation chemical treatments.