Narrow linewidth picosecond UV pulsed laser with mega-watt peak power

Abstract

We demonstrate a master oscillator power amplifier (MOPA) burst mode laser system that generates 66 ps/402.5 MHz pulses with mega-watt peak power at 355 nm. The seed laser consists of a single frequency fiber laser (linewidth < 5 KHz), a high bandwidth electro-optic modulator (EOM), a picosecond pulse generator, and a fiber based preamplifier. A very high extinction ratio (45 dB) has been achieved by using an adaptive bias control of the EOM. The multi-stage Nd:YAG amplifier system allows a uniformly temporal shaping of the macropulse with a tunable pulse duration. The light output from the amplifier is converted to 355 nm, and over 1 MW peak power is obtained when the laser is operating in a 5-μs/10-Hz macropulse mode. The laser output has a transform-limited spectrum with a very narrow linewidth of individual longitudinal modes. The immediate application of the laser system is the laser-assisted hydrogen ion beam stripping for the Spallation Neutron Source (SNS).

High efficiency laser-assisted H− charge exchange for microsecond duration beams

“…The three-stage Nd:YAG amplifiers pumped by flash lamps provide 6 orders of magnitude power amplification to the input macropulse, and the amplified IR light is subsequently converted to its third harmonic by two lithium triborate crystals [17]. The pulse width of the UV beam has been characterized using a multifunctional optical correlator [18].…”

Laser and optical system for laser assisted hydrogen ion beam stripping at SNS

“…The amplified IR macropulses are converted to the UV light using a 25 mm long LBO doubler and a 30 mm long LBO tripler. More details of the amplifier can be found in the previous paper [13]. The amplifier was designed to generate 1 MW (peak power) UV pulses bunched in 10-us@10-Hz macropulses.…”

4 mJ Rectangular- Envelope GHz-Adjustable Burst-Mode Fiber-Bulk Hybrid Laser and Second-Harmonic Generation

“…Substantial researches have been reported on the high power burst-mode pulse lasers. To produce sufficient peak power and offer flexibility of pulse parameters, almost all of the burst-mode laser systems involve a master oscillator power amplifier (MOPA) configuration [15][16][17][18][19][20][21][22][23][24]. To generate the burst-mode seeds, time gating high repetition rate mode-locked or gain-switched pulses is one popular method [15][16][17][18].…”

“…Continuous laser modulated by two electrical optic modulators (EOM) could realize all-temporal-parameter adjustable burst-mode seed with the advantages of stability and technological maturity [22], however, the power of seed is severely limited by the power capability of the EOM. Fiber cascading bulk hybrid amplifier merges the advantages of fiber and bulk amplifiers, and impressively promote the peak power of narrow linewidth burst lasers to ~MW, where an elaborately designed high gain pre-amplifier or additional ASE suppression in bulk amplifier is required due to limited output energy of fiber lasers for the nonlinear effects [22][23][24].…”