Phase-Matching Optimization of Laser High-Order Harmonics Generated in a Gas Cell Phase-Matching Optimization of Laser High-Order Harmonics Generated in a Gas Cell
Restricting the laser beam with an 8 mm aperture in front of the focusing lens increases the emission of most harmonic orders observed by as much as an order of magnitude. Optimal harmonic generation pressures were found to be about 55 torr in neon and 110 torr in helium. The optimal position of the laser focus was found to be a few millimeters inside the exit foil of the gas cell. Probing with counter-propagating light reveals that in the case of neon the harmonics are generated in the last few millimeters before the exit foil. In helium, the harmonics are produced over a longer distance. Direct measurement shows that the re-absorption limit for mid-range harmonics in neon has been reached.
School:Brigham Young University
School Location:USA - Utah
Source Type:Master's Thesis
Keywords:high order harmonic generation intensity laser harmonics non linear optics euv extreme ultra violet light sources soft x rays optimization phase matching
Date of Publication:06/29/2005