A modelocked semiconductor laser for a polarized electron source

We have constructed a prototype compact laser system based on GaAlAs semiconductor diodes. It has been designed specifically to be used with strained GaAs type photocathodes as a source for CW electron accelerators. It produces pulses of picosecond duration, at a repetition rate that can be set anywhere between 0.3 and 3 GHz. The system operates at average powers up to 150 mW, and the semiconductors that are presently installed emit at a wavelength of 847 nm with a 4 nm tuning range, though these can be easily substituted to give a 70 nm tuning range.