Non-linear absorption of 1.3-mu m wavelength femtosecond laser pulses focused inside semiconductors: Finite difference time domain-two temperature model combined computational study

I. B. Bogatyrev , D. Grojo (1) , P. Delaporte (1) , S. Leyder , M. Sentis (1) , W. Marine (2) , T. E. Itina

1 LP3 - Laboratoire Lasers, Plasmas et Procédés photoniques
2 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille

We present a theoretical model, which describes local energy deposition inside IR-transparent silicon and gallium arsenide with focused 1.3-mu m wavelength femtosecond laser pulses. Our work relies on the ionization rate equation and two temperature model (TTM), as we simulate the non-linear propagation of focused femtosecond light pulses by using a 3D finite difference time domain method. We find a strong absorption dependence on the initial free electron density (doping concentration) that evidences the role of avalanche ionization. Despite an influence of Kerr-type self-focusing at intensity required for non-linear absorption, we show the laser energy deposition remains confined when the focus position is moved down to 1-mm below the surface. Our simulation results are in agreement with the degree of control observed in a simple model experiment. (C) 2011 American Institute of Physics. [doi:10.1063/1.3662192]

Domaines: Optique / photonique

I. B. Bogatyrev, D. Grojo, P. Delaporte, S. Leyder, M. Sentis, et al.. Non-linear absorption of 1.3-mu m wavelength femtosecond laser pulses focused inside semiconductors: Finite difference time domain-two temperature model combined computational study. Journal of Applied Physics, 2011, 110 (10), ⟨10.1063/1.3662192⟩. ⟨hal-01418627⟩