It is demonstrated that the incorporation of variable pulse duration flashlamp power supplies into an Nd:YAG burst mode laser system results in very substantial increases in the realizable energy per pulse, the total pulse train length, and uniformity of the intensity envelope. As an example, trains of 20 pulses at burst frequencies of 50 and $20\mathrm{kHz}$ are demonstrated with individual pulse energy at $1064\mathrm{nm}$ of 220 and $400\mathrm{mJ}$ , respectively. Conversion efficiency to the second- ( $532\mathrm{nm}$ ) and third- ( $355\mathrm{nm}$ ) harmonic wavelengths of $\sim 50\%$ and 35–40%, respectively, is also achieved. Use of the third-harmonic output of the burst mode laser as a pump source for a simple, home built optical parametric oscillator (OPO) produces pulse trains of broadly wavelength tunable output. Sum-frequency mixing of OPO signal output at $622\mathrm{nm}$ with residual output from the $355\mathrm{nm}$ pump beam is shown to produce uniform bursts of tunable output at $\sim 226\mathrm{nm}$ , with individual pulse energy of $\sim 0.5\mathrm{mJ}$ . Time-correlated NO planar laser induced fluorescence (PLIF) image sequences are obtained in a Mach 3 wind tunnel at $500\mathrm{kHz}$ , representing, to our knowledge, the first demonstration of NO PLIF imaging at repetition rates exceeding tens of hertz.