A simple method of producing pulsed coherent radiation at 337.1 nm with variable pulse durations of 2.0–3.5 ns using a small transversely excited N2 laser is described. For laser operation in a moderately broad range of gas pressure (up to 1 atm), a weak surface corona discharge has been utilized as a preionizer. The electrical excitation is a flat plate Blumlein circuit with the main electrodes fixed at a height of 35 mm above the corona streamers. The laser produces an output peak power in excess of 70 kW at 350 Torr gas pressure and pulse repetition rate of 10–50 Hz.

For the first time, to the best of our knowledge, a green (520 nm) and amber (592 nm) light emitting diode-pumped Nd:YAG laser is reported. The laser oscillator is a stable semi-planar resonator with a total length of 140 mm. The green (amber) light emitting diode-pumped laser produced a 107 (52) µJ laser energy, at 2.6 (0.7) J electrical pump energy. The oscillator operated at a low repetition rate (about 0.1 Hz) in free-running mode, where the laser spikes were initiated about 210-280 µs after the leading edge of the pump pulse. Moreover, the transverse mode profiles of the resonator, pump absorption efficiency, and optical gain have been studied in some detail.

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In this paper, the mode structure and time behavior of a LED-pumped Ce:Nd:YAG laser have been studied. Four blue LED bars with total 128 LEDs at 460 nm are utilized to pump a 3 mm diameter laser rod. Using a Cr 4+ :YAG passive optical switch with 96% initial transmission, and a low loss stable optical resonator and 0.7 J pumping energy, a single 17 micro-joules Q-switched laser pulse with 240 ns pulse-width and nearly TEM 00 mode profile was produced. By increasing the pumping energy E p up to 0.8 J, the mode structure remained intact. Further increasing of E p , the laser mode changed to TEM 10 . Numerical calculations show that the central high gain area of the laser rod and saturation mechanism of the passive Q-switch behaves like as a soft aperture to enforce the laser resonator to oscillate on a low order transverse mode. For laser free-running, the TEM 00 mode has not been achieved and the optical resonator produced high order transverse mode patterns.