500Hz high-energy laser for PLIF application

Planar laser induced fluorescence (PLIF) diagnosis technology has been widely applied in flow field study and combustion diagnosis. Due to the complexity of the experimental environment of practical PLIF applications, The PLIF diagnostic system needs a good environment adaptation. In this paper, we reported a high energy Nd:YAG MOPA laser with repetition rate of 500Hz, which was applied in PLIF diagnostic system. A diode-laser side-pumped Nd:YAG module, which was pumped from five directions and optimized for better gain distribution, was employed to build a EO Q-switched Nd:YAG oscillator. A stable structure design of oscillator resonant cavity was used to improve the environmental adaptability of Nd:YAG laser. In our environmental adaptation experimentation, the laser oscillator has an energy fluctuation of <5% in the temperature range from 5°C to 45°C. In order to scale the pulse energy to meet the PLIF system requirements, we employed three 2500W diode-laser five-direction-side-pumped Nd:YAG modules as laser amplifiers to build MOPA system. Finally, the laser pulse energy of ∼18mJ was amplified to 68mJ at 1064nm. Using KTP crystal as a frequency doubling crystal, we obtained a pulse energy of 35.6mJ at 532nm. The developed Nd:YAG laser has been used in our 500Hz-PLIF diagnostic system successfully.