Berlin 2005 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 5: Poster Nichtlineare Optik

Q 5.11: Poster

Freitag, 4. März 2005, 11:00–12:30, Poster HU

Transverse Patterns in Vertical Cavity Surface Emitting Lasers With a Large Square Aperture — •Malte Schulz-Ruhtenberg¹, Thorsten Ackemann¹, and Kai Feng Huang² — ¹Institut für Angewandte Physik, Universität Münster, Münster, Deutschland — ²Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan

We investigate the emission of Vertical Cavity Surface Emitting Lasers (VCSELs) with a large square aperture (40µm by 40µm). These devices have a relatively high output power compared to smaller VCSELs and are still longitudinal single mode. However, the coherence is limited because of multimode emission in high-order modes in the transverse direction. Due to the large Fresnel number tilted waves are favored in the devices and patterned emission is observed.

The length scales of the transverse patterns depend on the detuning between the Fabry-Perot resonance of the cavity and the gain maximum of the active zone, which can be controlled by adjusting the temperature of the laser diode. We study near-field as well as far-field emission patterns, polarization behavior and spectra. In particular, the dependence of the transverse wave vectors on the detuning is measured quantitatively. For high detuning, the pattern contracts on a few, rather well-defined Fourier modes.