Optically pumped semiconductor disk laser with graded and step indices

F. Saas, V. Talalaev, U. Griebner, and J.W. Tomm
Max-Born-Institut, Max-Born-Str. 2 A, 12489 Berlin, Germany

M. Zorn, A. Knigge, and M. Weyers
Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany

Published in:
Appl. Phys. Lett. 89, 151120 (2006).
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Abstract:
Results of a study of different gain section designs in nonresonantly optically pumped vertically emitting semiconductor disk lasers (SCDLs) are presented. Clear superiority of structures with barriers based on graded-gap layers is demonstrated. This finding is assigned to the lack of absorption saturation within the barriers caused by the efficient carrier collection capabilities of graded structures compared to ungraded ones. Transient photoluminescence experiments providing direct access to the carrier transfer from the barrier to the quantum-well active region confirm this explanation. Consequently, the authors propose graded designs for SCDLs.