Darmstadt 2008 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 9: Laserentwicklung (Halbleiterlaser)

Q 9.10: Talk

Monday, March 10, 2008, 18:45–19:00, 3H

Waveguide mode dynamics of (Al,In)GaN Laser Diode — •Ulrich Schwarz and Harald Braun — Institute for Experimental and Applied Physics, University of Regensburg, D-93040 Regensburg, Germany

We measure the waveguide mode dynamics of (Al,In)GaN laser diodes emitting in the near UV to blue wavelength range. The combination of a scanning near--field microscope (SNOM) with a high spectral resolution monochromator and/or temporal resolution allows collecting multi--dimensional data sets (space, time, and wavelength) of the laser diode during pulsed operation. For highest temporal resolution --- to measure relaxation oscillations and delay of lasing onset --- we use a streak camera in combination with the SNOM. The measurements are then compared with basic simulations within the framework of rate equations. The central question is whether the physical effects which are particular for the group III-nitrides (i.e. carrier localization caused by indium fluctuations and quantum confined Stark effect) result in a fundamentally different behavior when compared to standard laser diodes operating in the red and infrared spectral region. We demonstrate how optical gain measurements already indicate the impact of indium fluctuations on (Al,In)GaN laser diode properties.