Set temperature dependence of fractional thermal loading andeffective stimulated emission cross section of a diode double endpumped TEM00 Nd:YAG laser for micromachiningapplication

Abstract

We discuss the set temperature dependence of fractionalthermal loading and effective stimulated emission cross section ofan efficient, diode double end -pumped Nd:YAG laser using two 30 Wpump diodes with a CW output power greater than 8 W in polarizedTEM00 mode near-diffraction limited beam suitable formicromachining applications of ultra hard materials like diamond.The temperature dependence of effective stimulated emission crosssection for 4F3/2 → 4I11/2 transition andfractional thermal loading of Nd:YAG are determined where the pumppower induced thermal lensing is used to make the cavity stableand in thermally stabilized solid state lasers the cavityparameters change dynamically with the pump power and hence theoverlap integrals become a function of absorbed pump power. It isobserved that the fractional thermal loading is increasing withincrease in set temperature of laser crystal and effectivestimulated emission cross section is increasing almost linearlywith the increase in set temperature of laser crystal and pumplaser diodes up to 30°C the rated value of the pumpdiodes and thereafter the cross section decreases with increase intemperature.