3 August 2012 Self-limited ionization in bandgap renormalized GaAs at high femtosecond laser intensities
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Abstract
Theoretical modeling of photo-induced electron-hole plasma and bandgap dynamics in GaAs at high femtosecond laser intensities ( ∼ TW/cm2) employing a quantum kinetic formalism based on a generalized Boltzmann-type equation, predicts for the first time against expectations, the saturation of plasma densities despite the strong direct bandgap narrowing. Though the transient electronic bandgap renormalization provides a significant positive feedback for all relevant single-photon and impact ionization mechanisms, which is clearly observable at moderate (sub-TW/cm2) laser intensities, the counterintuitive plasma density saturation at higher laser intensities and high plasma densities ( ∼ 1022  cm−3) is dictated by much stronger negative feedback, originating from a highly-nonlinear transient enhancement of the corresponding Auger recombination coefficient for the shrinking bandgap. These theoretical predictions are in semi-quantitative agreement with the results of our time-resolved reflectivity infrared (IR)-pump experiments, which support this newly predicted process of self-limiting ionization dynamics in strongly photo-excited semiconductors, such as GaAs, with induced bandgap shrinkage.
© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)
Tzveta T. Apostolova, Tzveta T. Apostolova, Andrey A. Ionin, Andrey A. Ionin, Sergej Ivanovich Kudryashov, Sergej Ivanovich Kudryashov, Leonid V. Seleznev, Leonid V. Seleznev, Dmitriy V. Sinitsyn, Dmitriy V. Sinitsyn, } "Self-limited ionization in bandgap renormalized GaAs at high femtosecond laser intensities," Optical Engineering 51(12), 121808 (3 August 2012). https://doi.org/10.1117/1.OE.51.12.121808 . Submission:
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