Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 46: Poster 2
HL 46.16: Poster
Donnerstag, 29. März 2007, 15:00–17:30, Poster A
Near field measurements on 405 nm GaN laser diodes with different ridge widths — •Dominik Scholz1, Harald Braun1, Ulrich T. Schwarz1, Christian Rumbolz2, Stefanie Brüninghoff2, Alfred Lell2, and Uwe Strauss2 — 1Naturwissenschaftliche Fakultät II - Physik, Universität Regensburg — 2Osram Opto Semiconductors GmbH, Leibnizstr.2, 93055 Regensburg
We examine the waveguide mode dynamics of blue (405 nm) gallium nitride (GaN) based laser diodes with different ridge widths from 2 µm to 10 µm. We are able to do time resolved measurements of laser pulses and their dynamics in the near field and in the far field. Therefore we use a self-built scanning near field optical microscope (SNOM). The distance between tip and sample surface is controlled by a servo loop via damping of the resonance curve of a tuning fork attached to the tip. We get a distance of about 50 nm and a lateral resolution of 100 nm which is limited by the optical aperture of the tip. This resolution, in combination with time resolved measuring is good enough to measure the time evolution of laser pulses. We examine the dynamics of lateral modes, filamentation effects and beam steering. Depending on various ridge widths and different current densities we examine mode dynamics and the occurring filamentation effects. Beam steering can be observed in measurements from near field towards the far field.