文档介绍：fluorescence quantum efficiency and optical heating efficiency in laser
crystals and glasses by laser caiorimetry
Albert J. Ramponi and John A. Caird
Lawrence Livermore National LaboratOlY, University ofCalifomia, P. 0. Box 5508,
Livermore, California 94550
(Received 26 Oetober 1987; accepted for publication 2 February 1988)
A photocaloric technique is described for determining the ftuoreseence quantum efficiencies
and optical heating efficiencies of opticaHy active ions in laser materials. Optical absorption
within the sam pIe results in a temperature increase until the heat produced by the absorbed
power is balanced by heat leakage to the surroundings. The ftuorescence quantum efficiency
and opticaI heating efficiency are determined from a measure ofthe absorbed power, the
steady-state temperature, and the time constant associated with sample cooling following laser
excitation. An alternative analysis utilizing only thc absorbed power and the steady-state
temperature as a function of excitation frequency is also shown to yield quantum efficiencies
consistent with the first method. Theory and experiment are demonstrated by measuring thc
fluorescence quantum efficiency and optical heating efficiency for trivalent chromium in
gadolinium scandium gallium gamet. Measurements are also reported for several neodymium•
doped phosphate l