The interaction of intense laser pulses with semiconductors like silicon results in highly resolved energy transfer, leading to multi-photon ionization, impact ionization, and recombination processes, ultimately leading to thermal equilibrium. Various effects, such as strong-field driven high-harmonics generation (HHG), permanent structural alterations, melting, and ablation, can be observed during laser processing of silicon. Understanding the physics of this interaction is crucial for optimizing it for applications like nano-fabrication. Numerical models like the Density dependent Two-Temperature Model (nTTM) have been widely used to study laser excitation and damage in silicon. However, experiments show electron and hole dynamics evolve differently, and electrons and holes undergo faster relaxation compared to the entire system. The Three-Temperature Model (3TM) considers electrons, holes, and the lattice as separate systems. The study of surface structure dynamics during laser excitation is important to understand the formation of Laser-induced periodic surface structures (LIPss). The Real-Time Time Dependent Density Functional Theory (RT-TDDFT) will be used to study the interaction of intense laser pulses with different polarization effects with silicon films of varying thickness.
Indian Institute of Technology (IIT)
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