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Accession Number:
ADA247542
Title:
CO2 Laser Frequency Multiplication
Descriptive Note:
Corporate Author:
NAVAL WAR COLL NEWPORT RI
Report Date:
1992-02-01
Pagination or Media Count:
2.0
Abstract:
This month has seen increased second harmonic conversion efficiency, with a highest total energy conversion of 70. The increased sensitivity of phase matching at high conversions was observed. The thermal conductivity of Silver Gallium Sellumium was measured. The second harmonic conversion efficiency has been modeled and an experimental threshold for optical coating surface damage has been obtained. All of the harmonic generation experiments were performed with the grating-tuned oscillator heavily modulated depth 1.0 to yield 1.0 nsec pulses at 9.55 microns spaced by 40 nsec. The gain switched spike which contained about 10 pulses was isolated by reduction of the intracavity iris to a diameter of 0.96 cm, considerably below the 1.4 cm diameter needed for transverse mode selection, introducing sufficient loss to reject the pulse tail of 2 micro sec duration. The short pulse train was expanded and then directed off a converging mirror into the 80 cm amplifier gain length. At the exit the 132 spot radius was 9.25 cm and the AgGaSe2 crystal was exposed to fluences up to 1.7 Jcm2. Harmonic conversion efficiency up to 60 was measured in one run which has been used for modeling purposes, in which the maximum harmonic energy was 80 mJ. The peak intensity in the highest pulse of the most energetic pulse train was 170 MW cm-2.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
