STUDY OF EFFICIENCY IMPROVEMENT OF OPTICALLY PUMPED CA5(PO4)3F:ND AND CA5(PO4)3F:HO,CR.
Interim technical rept. 10 Dec 67-10 Jul 68,
WESTINGHOUSE RESEARCH LABS PITTSBURGH PA
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This report deals mainly with the growth and testing of a 6 inch by 0.29 inch laser rod of Ca5PO43FNd, and with the spectroscopy and chemistry of a potential laser material, Ca5PO43FHo,Cr. With respect to the Nd doped laser rod, a slope efficiency of 6.6 was obtained, somewhat less than had been anticipated. The reason for the lower than expected slope efficiency is primarily the higher than average scattering loss in the rod, amounting to 0.055cm. Measurements of these losses are reported, and some possible explanation given for their presence. On Ca5PO43FHo,Cr, absorption bands due to Cr were determined. These extend from approximately 0.45 microns to 1.4 microns, and appear to transfer their energy to Ho throughout this entire range. Fluorescence and excitation spectra for Ho were obtained at room temperature and 77K for various concentrations of Ho and Cr. An optimum range of concentrations of Ho and Cr was determined from the standpoint of making a workable laser. Calculations of laser thresholds indicate that thresholds for a 3 inch long Ho, Cr rod should be approximately 25 joules, somewhat higher than Ca5PO43FNd, but with potentially greater efficiencies above threshold. Author
- Lasers and Masers