Laser-Induced Symmetry Breaking in Energy Absorption of Silicon Induced by Intense Femtosecond Laser Pulse

The absorption of light by a crystal is critically influenced by the symmetry of its lattice [1]. Crystal symmetry usually defines the optical properties [2], the band structure of the sample, along with a number of other mechanical and thermal properties. However, the modification of crystals by ultrashort laser pulses routinely employs intensities of the order of 10
¹⁴
W/cm
²
. At such high intensity, the band structure of the material can be modified by various phenomena such as laser-dressing [3], band-gap renormalization and structural modifications (e.g., phase modification and defect incubation).