Abstract

Femtosecond laser pulses can induce structural modifications in bulk glass. In this presentation, we report on the acquisition of multi-contrast images of structural modifications induced in BK7 glass with an LED array microscope. The femtosecond laser pulses at a repetition rate of 1 MHz were focused using an objective lens with numerical aperture of 0.4 in BK7 glass at the depth of 0.1 mm. Multi-contrast images such as bright-field images, dark-field images, and differential phase contrast images were obtained by electrically changing the illumination patterns of the LED array. We visualized structural modifications produced by different pulse energies and scanning speeds.

© 2018 Optical Society of Japan