Spectral and Up-Conversion Dynamics and Their Relationship to the Laser Properties of BaYb2F8:Ho3+
Abstract
The optical spectroscopic properties, energy transfer, up-conversion transitions, and lasing dynamics of BaYb2F8Ho3+ crystals are reported here. The positions of the various Stark components of the different J manifolds of Ho3+ are identified, and the branching ratios and radiative decay rates was calculated for the Ho3+ levels from the Judd-Ofelt theory. The fluorescence decay kinetics of the Ho3+ emission originating on the 5F5 and 5S2,5F5 levels and of the Yb3+ emission were measured nad analyzed with two energy-transfer theories. These calculations show that the Ho3+ - Yb3+ interaction is greater for ions initially in the 5F5 levels and that the diffusion of excitation energy among Yb3+ ions is a thermally assisted incoherent hopping process with a diffusion constant of 1.1 times 10 to the -10th power sq. cm. sec at 300 K. The kinetics of the up-conversion processes were modeled with rate equations. It was necessary to include the effects of stimulated emission at 551.5 nm and three successive energy transfers from Yb3+ to adequately describe the spectral dynamics of the upconversion. The efficiencies of the different laser transitions were found to be dependent upon the pump power used. The output of the shorter-wavelength transition (0.55 micrometers increases at the expense of the longer-wavelength transition (2.9 micrometers as the pump power is increased. The 2.9 micrometers laser action was found to have a 15% energy conversion efficiency and a slope efficiency of 4.5% when pumped at 1.047 micrometers. Reprints.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 15, 1988
- Accession Number
- ADA204063
Entities
People
- Guy D. Gilliland
- Leon Esterowitz
- Richard C. Powell
Organizations
- Oklahoma State University–Stillwater