Repetitive passive Q-switched diode pumped Yb:Tm:LiYF/sub 4/ laser around 1.5 /spl mu/m using various saturable absorbers

Summary form only. Repetitive Q-switched miniature laser sources around 1.5 /spl mu/m are useful tools for applications such as time-of-flight rangefinding. Until now, the only laser transition available in this wavelength region was the optical transition /sup 4/I/sub 13/2//spl rarr//sup 4/I/sub 15/2/ of erbium ions in phosphate glasses. However, it was pointed out recently that a continuous wave laser emission at 1.5 /spl mu/m based on the /sup 3/H/sub 4//spl rarr//sup 3/F/sub 4/ optical transition of thulium ions can be obtained easily in fluoride crystals such as LiYF/sub 4/ thanks to sensitization with Yb/sup 3+/ ions. The advantage of such codoping is that Yb/sup 3+/ ions act both as a sensitizer to absorb the emission from high power InGaAs laser diode and, at the same time, depopulate efficiently the lower /sup 1/F/sub 4/ level and recycle the energy up into the /sup 3/H/sub 4/ emitting level. Moreover, unlike the Er-glass system, Yb:Tm:YLF presents good thermomechanical properties allowing higher pulse repetition rates and average output powers.