Excitonic Nonlinear Optical Properties.
Abstract
Exciton and biexciton binding and excited state energies, and wave functions are calculated numerically via a finite element method in an effective mass approximation for GaAs quantum well disks and dots (including pyramid shaped structures) surrounded by an AlGaAs cladding. Moreover, the Al interdiffusion into the dot and the finite band offsets between the dot and the cladding have been included. For the range of dimensions studied, the inclusion of the Al interdiffusion had a pronounced effect on on the binding energies when compared to those obtained from the infinite barrier model. Using the results of the exciton and biexciton calculation, we calculate the third-order nonlinear optical susceptibility as a function of pump-probe frequencies in a range about the exciton absorption resonance. We restricted our calculation to the optical nonlinearity via the biexciton state arising from the population saturation of the exciton state. We expect, depending upon dot dimensions, broadening parameter(s) size, and the amount of pump detuning values of the imaginary parts of the susceptibilities to be on the order of -10 to -10(exp. -1) esu near resonance absorption due to biexciton formation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 12, 1996
- Accession Number
- ADA311109
Entities
People
- Frank L. Madarasz
- Robert O. Klepfer Iii
Organizations
- University of Alabama in Huntsville