Bistability vs stimulated scattering in semiconductor microcavities (original) (raw)
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Europhysics Letters (EPL), 2004
We demonstrate experimentally an unusual behavior of the parametric polariton scattering in semiconductor microcavity under a strong cw resonant excitation. The maximum of the scattered signal above the threshold of stimulated parametric scattering does not shift along the microcavity lower polariton branch with the change of pump detuning or angle of incidence but is stuck around the normal direction. We show theoretically that such a behavior can be modelled numerically by a system of Maxwell and nonlinear Schrödinger equations for cavity polaritons and explained via the competition between the bistability of a driven nonlinear MC polariton and the instabilities of parametric polariton-polariton scattering.
Off-branch polaritons and multiple scattering in semiconductor microcavities
2001
Exciton polaritons are the normal modes of the strong light-matter coupling in semiconductor microcavities. 1 Such half-light half-matter quasiparticles have sharply distorted energy dispersions and a pronounced nonlinear behavior, inherited from the cavity photon and quantum well exciton components, respectively. After the first nonlinear emission studies under nonresonant pumping, 2, 3 a significant acceleration of research has been devoted to the regime of resonant excitation.
Polariton–polariton interactions and stimulated scattering in semiconductor microcavities
2002
Recent work on polariton–polariton scattering in semiconductor microcavities under continuous wave excitation conditions is reviewed. For weak non-resonant laser excitation, a marked bottleneck in the polariton distribution is observed, but which is suppressed by polariton–polariton scattering as the laser intensity is increased. However, the high excitation conditions necessary to observe stimulated emission lead to loss of strong coupling and conventional lasing in the weak coupling regime.
Nonlinear Effects in Semiconductor Microcavity Polariton Emission
physica status solidi (a), 2000
Strong nonlinearities have been observed in the intensity and polarization degree of the emission from the bottom of lower polariton (LP) branch in a microcavity close to zero detuning between the uncoupled exciton and photon modes, under conditions of circularly polarized resonant excitation into the upper polariton branch. These nonlinearities are connected with stimulated scattering into spin polarized states at the bottom of LP branch.
Nonlinearities in emission from the lower polariton branch of semiconductor microcavities
Physical Review B, 1999
Stimulated scattering of spin-polarized lower branch polaritons ͑LP͒ arising from their bosonic character is reported. The observations are achieved in a microcavity close to zero detuning between the uncoupled exciton and photon modes, under conditions of circularly polarized resonant excitation into the upper polariton branch. The key role played by the bosonic nature of the LP states is demonstrated by measurements of the degree of circular polarization of the emitted light P LP . At low-excitation densities, P LP is of the order of 30% in the whole range of wave vectors kϽ2.10 4 cm Ϫ1 . However, at higher excitation intensities, P LP increases drastically, up to 80%, for LP's with kϷ0, and is accompanied by the appearance of strong nonlinearities in the LP emission intensity whilst P remains unchanged for weakly coupled polaritons with kϾ10 4 cm Ϫ1 . ͓S0163-1829͑99͒51040-0͔
Physical Review B, 2001
We have observed stimulated scattering in a II-VI microcavity at 80 K under nonresonant excitation conditions. This stimulated scattering manifests itself through probe amplification in a pump-probe reflectivity experiment and through a highly nonlinear emission at an energy corresponding to a k ʈ 0 state on the lower polariton branch. We were able to follow the onset and decline of stimulated scattering by measuring the temporal evolution of the probe amplification.
Direct evidence of reduced dynamic scattering in the lower polariton of a semiconductor microcavity
Physical Review B, 2000
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Polarization rotation in parametric scattering of polaritons in semiconductor microcavities
Physical Review B, 2003
Polarization of light emitted by a semiconductor microcavity in the regime of a resonant parametric scattering of the exciton polaritons shows extremely strong and unusual dependence on the polarization of pumping light. This dependence is interpreted here using the pseudospin model and in the framework of a quasiclassical formalism where the parametric scattering is described as resonant four-wave mixing. We show that the optically induced splitting of the exciton-polariton eigenstate, both in linear and circular polarizations, is responsible for the observed polarization effects. The splitting in circular polarizations, achieving 0.5 meV, has been detected experimentally, while the splitting in linear polarizations, which is much weaker, only manifests itself in the pseudospin dynamics of the exciton polaritons.