INVESTIGATION OF RADIATIVE AND NONRADIATIVE TRANSITIONS IN LASER CRYSTALS.
Abstract
The calculation of radiative transition probabilities between energy levels of rare-earth ions in crystals is reviewed. Magnetic-dipole, electric-dipole, and electric-quadrupole transitions are treated. Using L S coupled states for f(N) electronic configurations, all reduced matrix elements of the magnetic-dipole operator were computed. The reduced matrix elements of the unit tensor operators U(lambda) required for electric-dipole transitions were also computed for lambda = 2, 4, 6 using L S coupled states for f(1), f(2), and f(3). The relaxation processes for four different fluorescent levels of Eu(3+) in LaF3 were investigated using steady-state and pulsed selective excitation techniques. Different relaxation modes and rates were found for each level; both thermal and concentration quenching were studied. Using intermediate coupled states and fluorescence intensity measurements, the spontaneous emission probabilities for magnetic-and electric-dipole radiation were calculated and found to account for a large fraction of the observed lifetimes. The remaining relaxation and temperature and concentration effects are attributed to energy transfer arising from ion-ion interactions and decay by multiphonon emission. A survey is included of possible-rare-earth ions and transitions for lasers operating in the near-ultraviolet spectral region. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1967
- Accession Number
- AD0712309
Entities
People
- Marvin J. Weber
Organizations
- RTX