Diffraction gratings ablated on Lithium niobate single crystal byfemtosecond pulses

摘要

The surface diffraction gratings on lithium niobate single crystal ablated by a femtosecond laser pulse at a wavelength of800 nm have been investigated. The diffraction efficiencies of the gratings ablated with various parameters weremeasured by He-Ne laser at a wavelength of 632.8 nm. The 1-order diffraction efficiencies of the gratings improve from1.7% to 2.3% with the increase of ablation speed from 20μm/s to 200μm/s, and decrease from 1.9% to 1.3% with theincrease of pulse energy from 70nJ to 110nJ, respectively. The experimental and theoretical results show that thediffraction efficiencies of gratings can be improved by increase of ablation speed and grating constant or decrease ofpulse energy.