Experimental Study of the Solid State IR Vibrational Laser
Abstract
During the past grant period the mechanism behind the nonresonant UV pumping of the IR vibrational fluorescence for CN(-) in alkali halide crystals has been determined. First an F-center is produced by two UV photon absorption, then the F-center is ionized by another UV photon producing a free electron far up in the conduction band and finally this electron loses its excess kinetic energy by inelastic collisions with the CN(-) molecules. This experimental testing of solid state vibrational laser concepts has revealed a new solid state pumping mechanism, namely, the possibility of optically generated conduction electrons preferentially exciting the molecular vibrational modes. In another series of experiments, the low temperature energy relaxation times of the SH(-) stretching vibration in five different alkali halide hosts were measured by incoherent laser saturation and by persistent spectral hole-burning and were found to vary from 20 to 250 ps. These times are about 10 to the 8th power smaller than previously found for the stretching mode of CN(-) in these same hosts. Additional spectroscopic measurements show that the normalized strength of the vibrational sideband for SH(-) is roughly equal to that measured for CN(-), suggesting that the dynamical coupling of the stretching mode to phonons, librations, and localized modes is comparable for SH(-) and CN(-) in contrast with the radically different lifetime measurements.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 07, 1992
- Accession Number
- ADA249261
Entities
People
- A. J. Sievers
Organizations
- Cornell Laboratory of Atomic and Solid State Physics