Lattice deformation in laser-irradiated silicon crystal studied by picosecond X-ray diffraction

Lattice deformation in laser-irradiated Si(1 1 1) has been studied by picosecond X-ray diffraction at a delay time of 350 ps. The rapid thermal expansion (0.24% at maximum) was observed at 2.0 GW/cm2 irradiation. By irradiation above dielectric breakdown threshold (10.0 GW/cm2), the intense lattice compression (2.1% at maximum) was observed. The compression is caused by the laser ablation due to dielectric breakdown.