Development of high repetition rate VUV lasers

[摘要] The work described in this thesis was aimed at developing a field ofexpertise in short wavelength lasers within the department of Physics andAstronomy at St. Andrews University. Electrical discharge pumping wasselected as the excitation mechanism while the Lyman band of hydrogenwas identified as the initial target for the vacuum ultraviolet work. Dueto the short upper state lifetime of the laser transition (~0.8ns), fastvoltage pulse risetimes and an accurately timed, travelling electricalexcitation wave matched to the speed of light in the discharge wererequired.Initial work succeeded in producing voltage pulses at highrepetition rates having leading edges exhibiting risetimes of under300psec with voltage magnitudes in the 30-40kV regime. This wasachieved by designing and building non-linear ferromagnetic shock lineswhose purpose was to sharpen the output pulse from a thyratron having arisetime of 40-50ns. Voltage pulse risetime reductions on this magnitudehave not been seen previously in the literature by this author. By theaccurate timing of the outputs of ten such lines placed in parallel, thetravelling electrical excitation wave could be created. Allied to workconducted simultaneously upon flat plate Blumlein driven hydrogenlasers, this culminated in the production and operation of a thyratrondriven, sectional longitudinal hydrogen laser capable of high repetitionrates. This is the first of its type of which this author is aware.Laser pulse energies of 4.7μJ on the 160nm Lyman band transitionswere observed while the only limitation encountered in running the laserat multi-kilohertz repetition rates in burst mode was that imposed by thecharging rate of the available power supply. Despite this, 1kHz operationof a hydrogen laser was amply demonstrated for the first time.

[发布机构] University:University of St Andrews;Department:Physics & Astronomy (School of)