Regensburg 2007 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 46: Poster 2
HL 46.18: Poster
Thursday, March 29, 2007, 15:00–17:30, Poster A
Study of normal mode coupling in vertical-cavity surface-emitting laser structures by modulation spectroscopy — •Björn Metzger1, Peter Klar2, and Wolfram Heimbrodt1 — 1Department of Physics and Material Sciences Center, Philipps-University of Marburg, Germany — 2Physics Institute, Justus-Liebig-University of Giessen, Germany
Modulation spectroscopic methods are particularly suitable for characterizing vertical-cavity surface-emitting laser (VCSEL) structures. Many VCSEL structures studied so far show only a weak coupling between the cavity mode and the lowest quantum well exciton in the active region. The spectral line shapes of the corresponding Δ R/R signals in and off resonance are well understood. However, there are less reports about modulation spectroscopic studies of VCSEL structures with normal mode coupling in the vicinity of resonance and in the strong coupling regime. Here we present contactless electroreflectance (CER) results in the vicinity of resonance on a VCSEL structure with 12 strain-compensated (Ga,In)As/Ga(P,As) quantum wells in the active region of a 2 λ -cavity exhibiting normal mode coupling. The cavity detuning was varied by changing the sample temperature. The CER spectra obtained will be discussed and analyzed in the framework of model calculations and will be compared to those measured on VCSELs in the weak coupling regime.