Multi-output Q-switched solid-state laser using an intra-cavity MEMS micromirror array
Ralf Bauer, Walter Lubeigt, Deepak Uttamchandani
Univ. of Strathclyde (United Kingdom)
Caspar Clark, Euan McBrearty
Helia Photonics Ltd. (United Kingdom)
Proc. SPIE 8599, Solid State Lasers XXII: Technology and Devices, 85990T (March 6, 2013); doi:10.1117/12.2003609
Multiple individually-controllable Q-switched laser outputs from a single diode-pumped Nd:YAG module are presented by using an electrostatic MEMS scanning micromirror array as cavity end-mirror. The gold coated, 700 μm diameter and 25 μm thick, single-crystal silicon micromirrors possess resonant tilt frequencies of ~8 kHz with optical scan angles of up to 78°.
Dual laser output resulting from the actuation of two neighboring mirrors was observed resulting in a combined average output power of 125 mW and pulse durations of 30 ns with resulting pulse energies of 7.9 μJ and 7.1 μJ. The output power was limited by thermal effects on the gold-coated mirror surface. Dielectric coatings with increased reflectivity and therefore lower thermal stresses are required to power-scale this technique. An initial SiO2/Nb2O5 test coating was applied to a multi-mirror array with individual optical scan angles of 14° at a resonant tilt frequency of 10.4 kHz.
The use of this dielectric coated array inside a 3-mirror Nd:YAG laser cavity led to a single mirror output with average Q-switched output power of 750 mW and pulse durations of 295 ns resulting in pulse energies of 36 μJ. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Lasers ; Microelectromechanical systems ; Q switching ; Mirrors ; Gold ; Reflectivity ; Scanning ; Silicon ; Thermal effects ; Nd:YAG lasers