Münster 1999 – scientific programme

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HL: Halbleiterphysik

HL 48: Postdeadline III

HL 48.2: Talk

Friday, March 26, 1999, 13:45–14:00, H3

Strain distribution of high power lasers under operation by synchrotron radiation — •Ute Zeimer¹, J. Grenzer², U. Pietsch², A. Mazuelas³, T. Baumbach⁴, D. Lübbert⁴, and G. Ebert¹ — ¹Ferdinand- Braun- Institut, Berlin — ²Institut für Physik, Universität Potsdam — ³ESRF Grenoble, France — ⁴Fraunhofer- Institut für Zerstörungsfreie Prüfverfahren, Dresden

High power broad area laser diodes with λ = 808nm and optical output powers > 1W/facet are used as pumping sources for solid-state lasers as well as for direct applications in in medicine. Inhomogeneities and high strain lead to degradation processes limiting the laser lifetime. While the p-side laser metallisation prevents strain investigation by direct optical methods, high resolution X-ray diffraction (HRXRD) was applied. To penetrate the 1 µ m thick metallisation a high brilliance high intensity synchrotron source and a spatial resolution of about 40 µ m were necessary. The aim of the experiment was to characterize the strain status in the laser before and the changes during laser operation and degradation. The optical output power of the laser was monitored by a Si-photodiode. During the rapid degradation of the optical output power a small change in the strain status was observed by HRXRD.