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

We present a theoretical model, which describes local energy deposition inside IR-transparent silicon and gallium arsenide with focused 1.3- μ m wavelength femtosecond laser pulses. Our work relies on the ionization rate equation and two temperature model (TTM), as we simulate the non-linear propaga...

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Bibliographic Details
Published in:Journal of applied physics 2011-11, Vol.110 (10), p.103106-103106-10
Main Authors: Bogatyrev, I. B., Grojo, D., Delaporte, P., Leyder, S., Sentis, M., Marine, W., Itina, T. E.
Format: Article
Language:English
Subjects:
Engineering Sciences
Optics
Photonic
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Summary:We present a theoretical model, which describes local energy deposition inside IR-transparent silicon and gallium arsenide with focused 1.3- μ 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.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.3662192