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Quantum-Well and Cavity-Mode Resonance Effects in a Vertical-Cavity Surface-Emitting Laser Structure, Observed by Photoreflectance Using Hydrostatic Pressure and Temperature Tuning

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1999

Year

Abstract

Photomodulated reflectance (PR) and conventional reflectance (R) measurements as a function of hydrostatic pressure (up to 1.24 GPa) and temperature (150 to 310 K) were performed on an InGaAs/GaAs/AlAs vertical-cavity surface-emitting laser (VCSEL) structure. Both the cavity mode and the ground-state quantum well (QW) transition could be clearly observed in the PR spectra at all temperatures and pressures, whereas the corresponding R spectra reveal only the cavity mode clearly. Close to the resonance between cavity mode and QW exciton, achieved either by tuning the temperature at a fixed pressure or vice versa, an enhancement of the PR response by almost an order of magnitude was observed. The PR results have been analysed in terms of the lineshapes of the QW exciton and cavity mode and their importance for VCSEL characterisation and fabrication has been discussed.