Biomedical subjects

Stephan W Koch

Publications and source records attributed to Stephan W Koch.

3 recordsLinked to original sources

PubMed2006

Multichip vertical-external-cavity surface-emitting lasers: a coherent power scaling scheme.

We propose an efficient coherent power scaling scheme, the multichip vertical-external-cavity surface-emitting laser (VECSEL), in which the waste heat generated in the active region is distributed on multi-VECSEL chips such that the pump level at the thermal rollover is significantly increased. The advantages of this laser are discussed, and the development and demonstration of a two-chip VECSEL operating around 970 nm with over 19 W of output power is presented.

Journal Article↗

PubMed2006

Closed-loop design of a semiconductor laser.

We provide what we believe is the first closed-loop prediction of a semiconductor laser performance using fully microscopic many-body models for the spontaneous emission, gain, and carrier recombination losses due to Auger processes without having to resort to phenomenological adjustable fit parameters.

Journal Article↗

PubMed2005

Transition between different coherent light-matter interaction regimes analyzed by phase-resolved pulse propagation.

We present phase-resolved pulse propagation measurements that allow us to fully describe the transition between several light-matter interaction regimes. The complete range from linear excitation to the breakdown of the photonic bandgap on to self-induced transmission and self-phase modulation is studied on a high-quality multiple-quantum-well Bragg structure. An improved fast-scanning cross-correlation frequency-resolved optical gating setup is applied to retrieve the pulse phase with an excellent signal-to-noise ratio. Calculations using the semiconductor Maxwell-Bloch equations show qualitative agreement with the experimental findings.

Journal Article↗