Investigation And Modelling Of Pump Saturation Effect On Thermal Load Of Yb:Yag Thin Disk Pumped At Various Wavelengths

Relations among absorption of pump beam, quantum defect and thermal load were investigated for pump wavelengths of 968 nm and near 940 nm in two independent, real-time measurement experiments complemented with thermal distribution simulation. Saturation of absorption at 969 nm pumping for non-lasing operational regime, which affects temperature rise and exists independently of the thin disk type, disk head construction, pump power and pump beam diameter is reported. Disk temperature dependence of absorption, quantum defect and disk geometry and large difference between absorption, disk temperature and o-o efficiency at both pump wavelengths are discussed.