All semiconductor high power fs laser system with variable repetition rate

Laser diodes offer an interesting alternative to commercially available light sources for the generation of ultrashort pulses. They have the unique feature that they can be directly electrically pumped and that the emission wavelength can be controlled over a huge spectral range by changing the composition of the laser material. Hence they have the potential of being a highly flexible, compact and cost effective light source. However there is a considerable chirp of the pulses generated by a diode laser as a consequence of the strong coupling of real and imaginary part of the susceptibility in the semiconductor. This problem is solved by using an external cavity with intracavity dispersion management. By applying this technique we are able to generate pulse durations with less then 200 fs if an additional external pulse compressor is used. By using such a cavity in a master oscillator power amplifier setup the peak power can be increased up to 6.5 kW. This enables a huge field of possible applications like time domain terahertz spectroscopy or material processing. Anyway for some applications like fluorescence lifetime imaging even the repetition rate of an external cavity laser is too high. To solve this problem an ultrafast semiconductor pulse picking element is implemented to reduce the repetition rate into the kHz region. In conclusion we will demonstrate a compact all semiconductor laser system which is capable to generate sub ps pulses with a high peak power and a variable repetition rate at central wavelength of approximately 840 nm.