Educational Objectives
l Einstein Coefficients
l Optical Pumping
l Diode Laser
l Threshold and Slope Efficiency
l Absorption of Nd:YAG Crystal
l Lifetime of Excited States
l Interference Filter
l Longpass Filter
Optical pumping of anNd:YAG crystal by the IR emission of a laser diode shows the absorptionbehavior of a laser medium. At a laser diode controller parameters liketemperature and current of the pumping diode are set and hence its emissionwavelength is defined. Therefore the spectral absorption profile of the crystalcan be traced. The fluorescence of the crystal is selected with a narrow bandinterference filter. The life time of the excited 4F3/2 state is measured by afast PIN photodiode. Varying the diode current the laser threshold and slopeefficiency of the diode laser are determined. The temperature dependency on thediode current is measured at constant wavelength.