TI-SAPPHIRE LASER PUMPED BY A FREQUENCY DOUBLED DIODE PUMPED ND-YLF LASER

We report on the operation of an all solid state tunable laser source based on the pumping of the tunable laser material Ti: sapphire by a frequency doubled diode pumped Nd: YLF laser. The Nd: YLF laser, which was pumped by two 1 Watt laser diodes, was mode-locked using frequency modulation (FM) mode-locking and simultaneously Q-switched to produce a high peak power envelope of mode-locked pulses. Frequency doubling was achieved by non-critical phase matching in MgO: LiNbO3 with conversion efficiencies up to 50%. The Ti: sapphire laser had a threshold of 4.8-mu-J absorbed pump and the maximum output achieved was 3-mu-J for 15.6-mu-J absorbed pump. This output was in the form of a 100 ns pulse of linewidth 23 nm when free-running and less than 1 nm when a tuning element was employed. The repetition rate of this laser was 500 Hz, thus the peak power is 30 W. The tuning ranged from 705 nm to 955 nm using two mirror sets and thus covered almost the whole gain bandwidth of Ti: sapphire.