Burst Mode Dye Laser System for 50 kHz OH-PLIF of Swirl Burner

In this work we demonstrate the application of a high-speed burst-mode dye laser system for planar laser-induced fluorescence (PLIF) of the hydroxyl radical (OH) at 50 kHz repetition rates with up to 12.5 millisecond burst envelopes (10 ms typ.) to a model gas-turbine combustor. The laser system consists of a custom master oscillator power amplifier architecture Nd:YVO4/Nd:YAG burst mode laser frequency doubled to 532 nm pumping a customized Sirah Credo dye laser operating at 566 nm and doubled to ~283 nm. The system produces bursts of pulses with full-width half-maximum pulse durations of 10 ns and average pulse energies of about 1 mJ/pulse at 283 nm with relatively consistent pulse energy across the entire 10 ms – 12.5 ms burst envelope. Simultaneous imaging of the laser sheet is performed to correct for spatial and temporal variations in the beam profile. Signal-to-noise ratios (SNR) were >40 for 50 kHz imaging.