Efficient High Energy Infrared Third Harmonic Generation in Gases and Liquids for Laser Fusion Applications. Final Technical Report, 1 March 1977-28 February 1979

摘要

The major accomplishments have included: (a) Achievement of 4% THG energy conversion efficiency for 8-nsec-duration input pulses in a liquid CO-O sub 2 medium (10-cm path length). (b) Measurement of the THG input-output characteristics in the saturation and pump-depletion regime. These measurements led to a more detailed theoretical analysis of two-photon resonant THG processes. (c) Achievement of 2% THG power conversion efficiency for 120-nsec-duration input pulses in liquid CO-O sub 2 -SF sub 6 mixtures. The THG efficiency was limited by laser-induced breakdown (LIB) for these longer input pulses. (d) Development of a theoretical model for two-photon resonant THG processes in different focusing geometries. (e) Numerical evaluaion of the model for parameter regimes where analytic solutions are not possible. (f) Measurement of liquid CO two-photon resonance parameters in various diluents. (g) Experimental verification of the calculated resonant third-order susceptibility for different CO concentrations. (h) Measurement of the nonresonant third-order susceptibility in liquid CO-O sub 2 . (i) Measurements of the wave-vector mismatch in liquid CO-O sub 2 mixtures by a novel interference technique in a double-pass geometry. (j) Development of phase-matching techniques for THG. (k) Sum frequency generation in liquid CO-O sub 2 mixtures. (l) Characterization of the LIB parameters of the cryogenic liquids. (m) Theoretical analysis of alternate systems for tripling of CO sub 2 laser radiation. (n) Theoretical analysis of HF gas as a tripling medium for HF laser radiation. (o) Construction of a 1- to 10-nsec pulse duration CO sub 2 laser facility and of cryogenic liquid Dewars with 10-cm to 1-m optical path lengths. (ERA citation 05:001639)