Ultrahigh laser pulse energy and power generation at 10 kHz

Abstract

This Letter presents results from a new master-oscillator, power-amplifier pulse-burst laser system demonstrating ultrahigh pulse energies greater than 2.0 J/pulse at 1064 nm with interpulse separations of 100 μs (10 kHz) for burst durations of 100 pulses. Each pulse generates peak powers exceeding 130 MW and an average power of approximately 20 kW is generated over a 100-pulse-burst. Pulse energies decrease by less than 10% over a 100 sequential pulses, demonstrating negligible "droop" over long-duration pulse trains. Second-harmonic generation of 532 nm with conversion efficiency greater than 50% is demonstrated for 100-pulse-burst durations.

100 kHz thousand-frame burst-mode planar imaging in turbulent flames

“…It appears from the formaldehyde layer thicknesses, both normal to and in the direction of flame propagation, that these effects are negligible for the current conditions. As shown in Table 1, the image series reported in this work represents a fivefold improvement in TDR over prior burst-mode PLIF measurements, which have been limited either in burst duration or repetition rate [4][5][6][7][8][9][10][11][12][13][14][15][16]. The measured SNR of 30 without pixel binning is comparable to those previously reported pulse-burst formaldehyde PLIF sequences [4,12] as well as to those in which pixel binning was employed [8].…”

“…The TDR reported in the current work and that of previous burst-mode measurements is summarized in Table 1 for comparison [4][5][6][7][10][11][12][13][14][15][16]. For many turbulent reacting flows of practical interest, a 10 ms time duration represents multiple cycles of fluctuations in the vector and scalar fields under investigation.…”

“…The limitations of continuously pulsed DPSS laser systems have been addressed, in part, by advancements in burst-mode laser technology. For example, the ∼10-100 times higher pulse energies of burst-mode lasers can be used to access a wider range of combustion parameters of interest at higher frame rates, including OH, CH, NO, CH 2 O, soot, fuel-tracer concentrations, mixture fraction, and velocity [4][5][6][7][8][9][10][11][12]. However, a key challenge for burst-mode laser systems has been the short burst duration (up to 200 frames) and, therefore, limited temporal dynamic range (TDR) [4].…”

All-diode-pumped quasi-continuous burst-mode laser for extended high-speed planar imaging

“…5(b) and 5(d). These parameters were used to generate up to 30 mJ pulse energy at 354.8 nm over a 30-ms burst duration, which captures transients that evolve over a longer time period than those observable with the 10-ms bursts achieved in previous work [22,24]. In this case the repetition rate was reduced to 5 kHz in order to maintain sufficient pulse energy near the end of the burst, as shown in Fig.…”

“…This system increased the duration of previously published burst-mode laser sequences by nearly tenfold with sufficient energy in a burst of 200 pulses to perform 20-kHz formaldehyde PLIF for the first time in a lifted methane-air diffusion flame. Subsequently, Fuest et al demonstrated a 10-kHz, 10-ms burst duration PBL system with up to 200 J per burst based on a solid-state pulsed master oscillator amplified through a chain of eight flashlamp amplifiers [24], although its utility for planar measurements was not evaluated.…”