Accession Number:

AD0921719

Title:

0.85 Micron Solid State Laser Material Evaluation. Part 3

Descriptive Note:

Semi-annual rept. no. 3, 5 Jun 1973-5 Jan 1974

Corporate Author:

SANDERS ASSOCIATES INC NASHUA NH ELECTRO-OPTICS DIV

Report Date:

1974-06-01

Pagination or Media Count:

91.0

Abstract:

This report describes the final phase of the program for the development of a 0.85 micron optically pumped laser material Er3YLF. Laser operation is obtained at room temperature in this material via stimulated 4 S 3 2 to 4 I 132 transitions. ErYLF is a true four-level laser. The relationship between growth parameters and feed purity and their effects on crystalline quality were investigated. Dramatic improvement in optical quality was obtained in growth runs using argon as the furnace cover gas. Preliminary evidence of further improvements in crystalline quality comparable to NdYAG resulted from the use of recrystallized feed. The physical properties of YLF are reviewed and the results applied to a calculation of the thermal loading at fracture of a YLF rod uniformly heated and cooled at the surface. The calculated value is 11 wattscm at thermal fracture corresponding to predicted output power of 7.6 wattscm. Spectroscopic studies focused on the effects of increased Er3 concentration on laser efficiency. The temperature and concentration dependence of the lifetime of the upper laser level were measured. In flashpumped operation at room temperature an optimum concentration of approximately 5 is predicted. Comparative measurements show significantly improved laser efficiency with Er3 concentration over the range 2-3.5. Improved laser performance was observed using rods grown in argon.

Subject Categories:

  • Lasers and Masers
  • Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE