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New mechanism of saturation absorption in semiconductors

Eugene V. Beregulin, Sergey Ganichev, K. Gloukh +1 more

Jan 1, 19880 citations

Semconductor Medium in the Transient Regime-I: Temporal and Spectral Effects

Neil Finlayson, Ewan M. Wright, G. I. Stegeman

The propagation of optical pulses in a semiconductor me- dium is modeled in the limit where the optical pulse width is assumed to be shorter than the interband recombination time of the semicon- ductor. Intense pulses cause saturation of the optical transitions, lead- ing to transient changes in the absorption and refractive index of the semiconductor. The changes in absorption and refractive index lead to distortions in the spectra of the pulses.

Jan 1, 19900 citations

Saturation in Semiconductor Absorbers and Amplifiers of Light

Frank Stern

Jan 1, 19665 citations

Two-level approach to saturation properties in semiconductor materials

F. de Rougemont, Robert Frey

Saturation properties of absorption, dispersion, and mixing susceptibilities in semiconductors have been described using the density matrix approach. This model, which takes into account both intraband thermalization and interband relaxation including Auger recombination, allows for numerical computation of the susceptibilities whatever the temperature and laser intensity are. As a simplification, an equivalent two-level system is derived which represents very well absorption and mixing susceptibilities for any laser wavelength, dispersion being correctly described by this model only when the pump frequency is close to or smaller than the band-gap energy. Such an equivalence is very easy to handle and allows for great simplification when the susceptibilities are introduced into the propagation equations.Saturation properties of absorption, dispersion, and mixing susceptibilities in semiconductors have been described using the density matrix approach. This model, which takes into account both intraband thermalization and interband relaxation including Auger recombination, allows for numerical computation of the susceptibilities whatever the temperature and laser intensity are. As a simplification, an equivalent two-level system is derived which represents very well absorption and mixing susceptibilities for any laser wavelength, dispersion being correctly described by this model only when the pump frequency is close to or smaller than the band-gap energy. Such an equivalence is very easy to handle and allows for great simplification when the susceptibilities are introduced into the propagation equations.

Physical review. B, Condensed matterJan 15, 198831 citations

Kinetics of induced nanosecond absorption in photorefractive InP:Fe

P. U. Halter, Jean Claude Fabre, Gérald Roosen

For understanding and optimization of the photo refractive gain it is important to know the basic parameters of photo-ionization and recombination processes. In the nanosecond regime the pulse energies required for maximum coupling gain in semiconductors easily reach the limit for saturation of the deep centers. especially if one of the recombination times is larger than the pulse duration. In that case, induced absorption (or bleaching) will appear due to a redistribution of the population of the different levels of the deep center and counterbalance photorefractive amplification. The present simultaneous study of the kinetics of the induced absorption and the photocurrent in an InP:Fe sample reveals a number of interesting parameters like electron and hole recombination times, ionization cross sections and Fe2+/Fe3+ concentrations.For understanding and optimization of the photo refractive gain it is important to know the basic parameters of photo-ionization and recombination processes. In the nanosecond regime the pulse energies required for maximum coupling gain in semiconductors easily reach the limit for saturation of the deep centers. especially if one of the recombination times is larger than the pulse duration. In that case, induced absorption (or bleaching) will appear due to a redistribution of the population of the different levels of the deep center and counterbalance photorefractive amplification. The present simultaneous study of the kinetics of the induced absorption and the photocurrent in an InP:Fe sample reveals a number of interesting parameters like electron and hole recombination times, ionization cross sections and Fe2+/Fe3+ concentrations.

Photorefractive Effects, Materials, and DevicesJan 1, 19900 citations

Negative absorption coefficient at indirect transitions in semiconductors

Nikolai G. Basov, Oleg N Krokhin, J. M. Popov

Acta Physica Academiae Scientiarum HungaricaeApr 1, 19624 citations

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