Semiclassical theory for a nonequilibrium steady state in microcavity semiconductor lasers

Abstract

Semiclassical equations for microcavity semiconductor lasers based on Maxwell‐semiconductor‐Bloch equations are solved for on‐lasing state (nonequilibrium steady state) with a steady state condition for eigenfrequencies. Results for a single mode operation can account for input‐output curves for laser operation, gain saturation accompanied by the spectral hole‐burning in the carrier distribution, and the shift of laser frequency.We found nonmonotonic dependency of the laser frequency on the pump intensity (excited carrier density) when the cavity mode is close to the exciton level. Effects of Coulomb interaction, and phase‐space filling are also discussed with reference to the case of homogeneously and inhomogeneously broadened two‐level atom lasers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

BEC–BCS-laser crossover in Coulomb-correlated electron–hole–photon systems

“…This is not an advantage but rather a disadvantage for the BEC because the system can be in thermal equilibrium 6 only when the 4 lifetime [5][6][7]. One typical example is the normal photon lasing 8 induced by stimulated emission of the cavity photons from the e-h plasma [29,30]: at the laser frequency, the stimulated emission becomes very fast and many carriers are expended. As a result, a dip is formed in the carrier distribution (kinetic hole burning) [29,30] because the thermalization processes can no longer supply the lost carriers at sufficient speed.…”

“…One typical example is the normal photon lasing 8 induced by stimulated emission of the cavity photons from the e-h plasma [29,30]: at the laser frequency, the stimulated emission becomes very fast and many carriers are expended. As a result, a dip is formed in the carrier distribution (kinetic hole burning) [29,30] because the thermalization processes can no longer supply the lost carriers at sufficient speed. This means that non-equilibrium features cannot be negligible at all.…”

“…In such a situation, the lasing operation can be well described by the Maxwellsemiconductor-Bloch equations (MSBE)-these are coupled kinetic equations with dampinginduced and thermalization-induced terms [30][31][32]. This approach explicitly treats the electrons and holes where the Coulomb interactions are included within the Hartree-Fock (HF) approximation.…”

“…This approach explicitly treats the electrons and holes where the Coulomb interactions are included within the Hartree-Fock (HF) approximation. However, the applicable range of carrier densities is limited to high-density regimes because it is assumed that the actual distribution is driven to approach the Fermi distribution under the relaxation time approximation [29,30]. More importantly, MSBE cannot reproduce the results under thermal equilibrium even though the damping term is set to zero, and a sufficiently small but finite thermalization rate is assumed.…”

Principles and Methods of Quantum Information Technologies

“…Conversely, past theories for describing the lasing operation, e.g. the Maxwell-Semiconductor-Bloch equations (MSBEs) [16,17], cannot recover such equilibrium statistical approaches. 2 The difficulty shown here has been one of problems to understand the underlying physics in exciton-polariton systems.…”