UV-induced color centers and gain measurements in Ce/sup 3 +/:YLiF/sub 4/

Technical Report · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5678341

Lim, Ki-Soo; Hamilton, D S

The origin of the laser performance limitation characteristis of Ce/sup 3 +/:YLF have been identified and studied. To understand how stable and transient absorption centers are produced, several experiments were done including temperature dependence of transient decay times, spectral characteristics, growth kinetics, thermal or optical bleaching of these centers, and pump energy dependence. It is shown that the production of these centers results from a resonant two-photon absorption process or excited-state absorption which ionizes trivalent cerium ions. Once in the conduction band, the electrons from the cerium ions can be trapped temporarily at other trivalent cerium sites or permanently pre-existing fluoride vacancies, resulting in transient or stable color centers respectively. In order to clarify the effects of these color centers on the laser gain, single pass gain measurements were done as a function of laser pump repetition rates for several different temperatures. The possibility to improve the Ce/sup 3 +/:YLF laser with thermal and optical bleaching of these absorption centers is discussed. The energy levels and structure of Ce/sup 3 +/:YLF is discussed with the absorption and fluorescence spectra, and the possibility of the thermal lensing effect is discussed. Experimental techniques used to characterize the process responsible for the transient absorption are presented. The stable absorption bands, which are observed along with the transient absorptions, are discussed, and their polarization dependence, growing, and bleaching are presented. The single pass gain measurements are presented to explain several lasing problems found in Ce/sup 3 +/:YLF, and possible gain improvement is discussed. (LEW)

• Research Organization: Connecticut Univ., Storrs (USA)
• DOE Contract Number: FG02-84ER45056
• OSTI ID: 5678341
• Report Number(s): DOE/ER/45056-6; ON: DE88005402
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
ABSORPTION
ALKALI METAL COMPOUNDS
AMPLIFICATION
CERIUM IONS
CHARGED PARTICLES
COLOR CENTERS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DATA
DOPED MATERIALS
ENERGY LEVELS
EXPERIMENTAL DATA
FLUORIDES
FLUORINE COMPOUNDS
GAIN
HALIDES
HALOGEN COMPOUNDS
INFORMATION
IONS
LASERS
LITHIUM COMPOUNDS
LITHIUM FLUORIDES
LITHIUM HALIDES
MATERIALS
NUMERICAL DATA
POINT DEFECTS
POLARIZATION
SOLID STATE LASERS
TRANSITION ELEMENT COMPOUNDS
VACANCIES
YTTRIUM COMPOUNDS
YTTRIUM FLUORIDES