INVESTIGATIONS OF VERTICAL-CAVITY SURFACE-EMITTING LASER BY PHOTOREFLECTANCE SPECTROSCOPY

We report photomodulated reflectance results on vertical cavity surfac e emitting laser structures. Photoreflectance spectra have been record ed under normal incidence at different temperatures between 9 and 300 K. The structure used is a lambda cavity grown in the AlGaAs-based sys tem emitting at a wavelength near 800 nm. We show that photoreflectanc e is a unique noninvasive tool to measure accurately the quantum well transition and the cavity mode alignment: both features can be disting uished very well. Furthermore, this technique offers the opportunity t o determine the electric field within the undoped region from Franz-Ke ldysh oscillations, and gives the Al composition of the barrier materi al in the cavity. (C) 1996 American institute of Physics.