Scaling studies on efficient Raman converters

Injection locking performance of a 1 micro sec XeF laser pulse and Raman converter scaling have been investigated. Narrowband ultraviolet radiation from a frequency-doubled dye laser has been used to control the linewidth and polarization of a long pulse-length electron beam-excited XeF laser. Linewidths of 0.004 nm have been achieved in the 353 nm band of the XeF (B yields X) Laser transition. Over 90% of the energy in the free-running laser pulse has been extracted in the narrowband injection-locked pulse. Ratios of injection signal power to output laser power on the order of .00001 are adequate for efficient injection-locking to occur. Efficient Raman conversion of microsecond-pulse, injection-locked XeF (353 nm) laser radiation into the blue-green region via the second Stokes shift in hydrogen has been demonstrated using a Raman oscillator-amplifier scheme. Strong depletion of the pump and the first Stokes radiation accompanied by a dominant second Stokes (500 nm) output was observed for the first time. Amplifier power conversion efficiency of 43% was achieved along with a blue-green output energy of 1.7 J at an energy efficiency of 34%. These data support Raman converter scaling analyses which predict feasibility of efficient XeF-to-blue-green conversion at higher energies.