Volume Bragg Grating Formation in Fused Silica with High Repetition Rate Femtosecond Yb:KGW Laser Pulses

Abstract

In this work we present results on volume Bragg grating formation inside the pure fused silica with the Yb:KGW femtosecond laser, operating at 300 kHz repetition rate and having pulse duration of 300 fs. Gratings were created by direct laser writing technique, translating the sample perpendicular to the focused laser beam and forming several grating layers in order to achieve diffraction efficiencies up to 57 %. The influence of writing pulse energy and the sample scanning speed on structure morphology are also discused. We have demonstrated that high repetition rate helps to decrease the manufacturing time of such devices: 1 mm × 1 mm grating, having 2 μm period, with thicknesses up to 60 μm was written in less than an hour.