Characterization of the heat loading of Nd-doped YAG, YOS, YLF, and GGG excited at diode pumping wavelengths

The thermal effect in a grazing-incidence slab laser with the novel composite cooling method

“…The major sources of heat production are quantum defect (Koechner 1999), non-radiative transition (Fan 1993), fluorimetric quenching induced by impurity and defect (Danielmeyer et al 1973), and the Auger recombination (Musgrave et al 2001). The fraction of pump power converted to heat η h is assumed as 0.28 which is a reasonable value confirmed by the previous experiments (Hodgson et al 1999;Koechner 1999;Comaskey et al 1995;Xiaoyuan et al 2002) when compared with the usual value of η h = 0.24 used in previous theoretical model that only considered the quantum defect (Hello et al 1994;Bermudez et al 2002). Then the steady-state temperature field in the crystal can be described with the classic heat conduction equation (Poisson equation) (Özışik 1980;Koechner 1999;Bermudez et al 2002),…”

Heat, fluorescence, and stimulated-emission power densities and fractions in Nd:YAG

“…The fits of (7)-(9) are represented by the fine dashed, course dashed, and solid lines, respectively. For (8), the constants are 256 s and 0.0742 (at.%) while for (9) they are 250 s 0.0132 (at.%) and 3.93. Visually, it can be seen that (7) and (9) give almost identical fits over the range of interest while (8) results in a fit that is far from optimum.…”

Effect of absorbed pump power on the quality of output beam from monolithic microchip lasers

“…Hence, the contribution from the aberration terms higher than the quartic or fourth order will be very small and can be neglected. Thus, the transmission profile of the thermal lens considering the quartic phase aberration only, can be written as t´rµ exp j´a 1 P abs r 2 a 2 P abs r 4 µ exp j r 2 2 f th a 2 P abs r 4 (8) where f th is the thermal lens focal length and its value is inversely proportional to the absorbed pump power, i.e., f th 1 2a 1 P abs (9) and the coefficient of the spherical aberration associated with the thermal lens is a 2 P abs . It can be found from eq.…”

“…The phase profile induced by the pumping beam creates a lensing effect inside the cavity and in this way the plane-plane cavity of a monolithic microchip laser reduces to an equivalent planoconcave resonator configuration. Thermal lensing and thermal beam distortions in end pumped solid state laser systems have been studied extensively for a long time both in edgeand face-cooled configurations [7][8][9][10]. Frauchiger et al gave the pump power induced temperature distribution as a power series expansion in the case of edge-cooled rod [9] whereas Cousins gave the temperature distributions as a Fourier-Bessel expansion for facecooled systems under thin disk approximation [10].…”