Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 10: Semiconductor Lasers I
HL 10.3: Talk
Monday, March 20, 2017, 10:00–10:15, POT 06
The impact of detuning on the performance of semiconductor disk lasers — Fan Zhang1, Christoph Möller1, Martin Koch1, Stephan Koch1, •Arash Rahimi-Iman1, and Wolfgang Stolz1,2 — 1Department of Physics and Materials Sciences Center, Philipps-Universität Marburg, D-35032 Marburg, Germany — 2NAsP III/V GmbH, Hans-Meerwein-Straße, D-35032 Marburg, Germany
After two decades of research and development, semiconductor disk lasers (SDLs), also referred to as vertical-external-cavity surface-emitting lasers (VECSELs), are recognized as advanced light sources offering a high-power output and excellent beam quality, while the lasing wavelength can be set by semiconductor bandgap engineering. In this work, we focus on an important, yet less-discussed factor, namely the detuning in SDLs. It is defined as the wavelength difference between the material gain and the longitudinal confinement factor (LCF) at room temperature. Due to device-to-device fluctuations, it is difficult to conduct direct experimental studies on the detuning. Therefore, a new approach is promoted to achieve different detunings from the same gain chip: by altering the cavity angle of a V-shaped cavity in which the VECSEL chip serves as a folding mirror. As the negative detuning is raised from -20 nm to -37 nm, a significant increment of the maximum output power by 70% is observed, while the lasing threshold is elevated from 7.4 W to 25.6 W due to the increased detuning. Yet, the modification of the intra-cavity incidence angle on the chip also leads to a shift of the emission wavelength of about 16 nm and enhances the tunability to 34 nm.