Accession Number : AD0802326

Title :   RESEARCH ON NONRADIATIVE PROCESSES IN LASER MATERIALS.

Descriptive Note : Summary technical rept. 1 Jul 64-30 Jun 66,

Corporate Author : HUGHES RESEARCH LABS MALIBU CA

Personal Author(s) : Asawa, C. K. ; Devor, D. P. ; Robinson, M. ; Stafsudd, O. M. ; Satten, R. A.

Report Date : OCT 1966

Pagination or Media Count : 126

Abstract : Two types of nonradiative processes for laser materials have been studied under this program: (1) direct interaction between the rare earth ion and the lattice, and (2) interaction between pairs of rare earth ions in the crystal. The temperature-concentration behavior of fluorescence of neodymium in the lanthanum trifluoride crystal has been studied. The long delayed fluoresence of neodymium in lanthanum trichloride and lanthanum trichloride containing cerium has been experimentally studied. These delays have yielded a way to determine the weak nonradiative coupling rates. The effect of ion-pair interaction on the efficiency of pumping a fluorescence level and depopulating certain levels of Nd(3+) was studied for lanthanum trifluoride containing neodymium and cerium; reduced Nd(3+) laser threshold was observed when cerium was incorporated in the crystal. The experimental results are described in terms of the formation of ion-pair states and resonance transfer. Results of a similar study of the effect of ion-pair interaction on the Er(3+) fluorescence when cerium is introduced as a second dopant in lanthanum trifluoride are also presented. The study of the lattice vibrations of lanthanum trichloride by means of Raman scattering has begun. The initial data from this study and their interpretation are presented. The selection rules for the two-phonon Raman processes are tabulated. Preliminary data for the vibronic spectra of NdCl(3) are presented.

Descriptors :   (*LASERS, MATERIALS), (*RARE EARTH ELEMENTS, HALOGENS), OPTICAL PUMPING, TEMPERATURE, RAMAN SPECTROSCOPY, QUENCHING, DOPING, HALIDES, LANTHANUM COMPOUNDS, FLUORIDES, CRYSTAL LATTICES, IONS, FLUORESCENCE, CHLORIDES, CERIUM COMPOUNDS, ABSORPTION SPECTRA, SYMMETRY(CRYSTALLOGRAPHY), NEODYMIUM COMPOUNDS, CRYSTAL GROWTH.

Subject Categories : Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE