Nonequilibrium gain in optically pumped GaInNAs laser structures

Abstract

A theory is presented which couples a dynamical laser model to a fully microscopic calculation of scattering effects. Calculations for two optically pumped GaInNAs laser structures show how this approach can be used to analyze nonequilibrium and dynamical laser properties over a wide range of system parameters.

Performance changes of a vertical‐external‐cavity surfaceemitting laser by an intra‐cavity anti‐reflex‐coating

“…Therefore, a more advanced model is introduced, which includes a microscopic description of the full carrier and polarization dynamics within the framework of the Semiconductor-Bloch equations (SBE) [11] for multiple carrier bands treated in singlet approximation. We include higher correlations via a plasmon pole approximation for screening, a T 2 time approximation for the polarization dephasing [14] and a microscopic relaxation rate approach for the carrier-carrier and carrier-phonon scattering [12,13]. An 8-band-k · p theory was used to calculate the electronic single particle band structure of the active material system, of which only the lowest conduction band and the heavy as well as the light hole bands are included for the description.…”

Microscopic modeling of the optical properties of semiconductor nanostructures

“…Thus, to assess the magnitude of non-equilibrium effects we have extended the model to take into account carrier densities fully dynamically, concentrating our calculations on optically pumped vertical external cavity surface emitting lasers (VECSEL) [16,17]. In order to access the long time scales required for pumping a laser into equilibrium and perform parameter studies, a simplified model relying on the extraction of scattering rates from microscopic calculations and using them in a rate approximation of scattering in the semiconductor Bloch equations was developed [18]. Fig.…”

Carrier Dynamics in Quantum Well Lasers

“…Many microscopic calculations so far were based on the quasi-equilibrium assumption where the carrier system is in thermal equilibrium with itself and the lattice. Extending the theory to nonequilibrium situations, carrier capture times in quantum-well lasers ) as well as the carrier distribution evolution after optical excitation (Thränhardt et al 2004) and effects of kinetic hole burning (Dery et al 2003a,b) can be calculated fully microscopically. In this publication, we take a close look at typical time scales of scattering (see Section 3) and at temperature changes induced by optical pumping (see Section 4).…”