Accession Number:

ADA256948

Title:

Radiationless Transitions and Excited-State Absorption in Tunable Laser Materials

Descriptive Note:

Final rept. 1 Jun 1989-31 Jul 1992

Corporate Author:

CONNECTICUT UNIV STORRS DEPT OF PHYSICS

Personal Author(s):

Report Date:

1992-09-01

Pagination or Media Count:

50.0

Abstract:

A coordinated experimental and theoretical investigation of fluorescence quenching and excited-state absorption was conducted on the chromium-doped halide elpasolites K2NaGaF6, K2NaScF6 and Cs2NaYC16, and on the laser-active T10l color center in KC1. Luminescence lifetime measurements on Cs2NaYC16Cr3 revealed a linear pressure dependence of the activation energy for thermal fluorescence quenching which was accurately predicted by a semi- empirical theoretical model incorporating quadratic coupling to an asymmetric mode. An ab-initio theoretical model, based on embedded-cluster and lattice- statics and dynamics calculations, accounted very well for optical and vibrational properties of these materials, but still needs refinement for reliable prediction of thermal quenching behavior. Two-photon excitation spectroscopy helped to explain broad-band excited-state absorption. Embedded- cluster calculations on laser-active color centers are in progress, with encouraging preliminary results. Non-radiative transitions, transition metals, chromium, tunable lasers, high pressure, luminescence, color centers.

Subject Categories:

  • Inorganic Chemistry
  • Lasers and Masers
  • Crystallography
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE