Energy storage and heating measurements in flashlamp-pumped Cr:Nd:GSGG and Nd:YAG

The authors have experimentally measured the energy stored and the heat generated in flashlamp-pumped Cr:Nd:GSGG for three Cr³⁺ concentrations in the range of 1-2×10²⁰ ions/cm³ . It has been found that the energy storage efficiency in these samples is 1.7 times greater than that of the Nd:YAG sample, and the normalized heating parameter χ, defined as the heat deposited per unit of stored energy, is 2.5 under the specified pumping conditions, with no evident dependence on the Cr³⁺ concentration. It has been been found that the measured χ value for the sample of Nd:YAG is 2.9 for the same pumping conditions. These observed χ values exceed expected values by factors of ~1.1 and 2 for the Cr:Nd:GSGG and Nd:YAG samples, respectively. The thermal focal length in the two materials was measured showing that the lensing is shorter in GSGG by a factor of 2.6 for the same available output power, or a factor of 4.5 for the same input pump power. The expected thermal lensing was determined using measured heat loads with no adjustable parameters, achieving satisfactory agreement with measured lensing values