Operation at high temperature of a diode-pumped passively Q-switched Nd:YAG/Cr 4+ :YAG laser

Compared with a conventional spark-ignition system, a laser-induced ignition of air-fuel mixtures in internal combustion engines presents many advantages, such as a higher probability to ignite leaner mixtures, no erosion effects, increase of engine efficiency, or shorter combustion time [1]. However, a laser used for ignition has to withstand hard-working conditions, such as high thermal and mechanical stress, or vibrations. A tough condition is imposed by the temperature, which should typically range from −40°C to 150°C. In this work we investigated the performances of a diode-pumped Nd:YAG laser passively Q-switched by Cr 4+ :YAG saturable absorber (SA) crystal, which is commonly used in engine ignition [2], for temperatures up to 150°C.