Accession Number : ADP008259

Title :   Spectral Hole Burning Between 2 K and Room Temperature in Sm2+ Doped Substitutionally Disordered Microcrystals,

Corporate Author : NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA

Personal Author(s) : Bilmers, R. ; Davis, J. ; Squicciarini, M.

Report Date : 22 MAY 1992

Pagination or Media Count : 3

Abstract : Filter operation is achieved by depleting the ground state population of molecules whose local environments are within the bandwidth of the hole-burning pump laser. Hole-burning is achieved in these systems via a mechanism known as triplet-trapping which is shown in Figure l. The first step in this mechanism is absorption from the ground singlet state, S sub 0, to the-first excited singlet state, S sub 1, in the dye molecule. For most laser dyes, most of the population returns to the ground state via prompt fluorescence. Some of the population, however, is transferred to the lowest-lying triplet state, T sub 1, via spin-orbit coupling assisted intersystem crossing. Typical branching ratios for intersystem crossing are approximately 10%. The lifetime of the T, to S sub 0 transition in solid matrices at low temperatures is very long. Tompkin and Boyd' reported a 2.5 S lifetime for fluorescein in boric acid glass at 200 K. This metastable triplet level therefore acts to trap population and prevent it from returning to the ground state.

Descriptors :   *MOLECULAR SPECTROSCOPY, *CRYSTALS, ABSORPTION, ACIDS, BORIC ACID, COMBUSTION, COUPLINGS, CROSSINGS, DYES, ENVIRONMENTS, FILTERS, FLUORESCENCE, GLASS, GROUND STATE, LASERS, MOLECULES, OPERATION, ORBITS, POPULATION, PUMPS, RATIOS, SOLIDS, TEMPERATURE, TRANSITIONS, TRAPS, LASER PUMPING, ABSORPTION SPECTRA, MOLECULAR STRUCTURE, DOPING, MODELS.

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE