DETERMINATION OF IMPORTANT PARAMETERS FOR 2ND-HARMONIC GENERATION IN LBO

The second harmonic generation (SHG) of lambda = 1.064 mum laser light in a lithium triborate crystal is investigated in a noncritical phase matching configuration, by temperature tuning the crystal. A simple method of measuring DELTAn, the difference in refractive indices that generates the wavevector mismatch in SHG, and its temperature derivatives was demonstrated. It was found that dDELTAn/dt is both wavelength and temperature dependent. The phase matching temperature obtained from the experiments is 148.5-degrees-C, with a temperature acceptance bandwidth of 4.2-degrees-C cm. A previously reported variation of this temperature in crystals of different origins is also explained.