An innovative solid-state laser for engine ignition

A compact high peak power, passively Q-switched, longitudinally diode-pumped laser was specially constructed for laser ignition. Nd:YAG was chosen as laser active medium and Cr4+:YAG as the saturable absorber medium. For pumping, a laser diode emitting at 808 nm with an output power of up to 300 W and pulse duration of up to 500 μs was employed. Experimental studies were carried out to find the optimum laser design parameters. These are the output coupler reflectivity, initial transmission of the saturable absorber, doping concentration of the Nd:YAG, oscillator length and the pump light distribution within the Nd:YAG crystal. Single pulses at 1064 nm with energies of 6 mJ and durations under 1.5 ns were achieved in a TEM00 mode.

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