Direct measurement of thermal lensing in Cr\u3csup\u3e3+\u3c/sup\u3e-doped colquiirities

A two-dimensional code that takes into account the quantum defect, upconversion, and thermal quenching of fluorescence has been developed. The code provides the spatial distribution of temperature, upper-state lifetimes, and heating sources within a laser rod under longitudinal pumping, for all the cloquiirite laser materials. The output of this code for a 4-mm-diameter, 1.5% Cr:LiSGAF rod is shown