Broadband operation of a gain-switched Ti:sapphire laser for measurements with the coherence radar

A gain switched Ti:sapphire laser with 350 mW average output power of near diffraction limited radiation and a bandwidth of more than 40 nm is presented. The Ti:sapphire laser was longitudinally pumped by a passively Q-switched and frequency-doubled Nd:YAG laser. The spectra of the radiation are investigated experimentally as a function of the pump energy. Time resolved measurements of the spectra and of the transversal mode structure show that the spectra and the transverse mode structure vary during one pump pulse of 1 ms. This variation of the spectrum was used to broaden the spectrum of the laser light. Finally we present measurements with the coherence radar on a dark object and with a large field of view.