  Effect of L-threonine (LT) doping on crystalline perfection, second harmonic
generation (SHG) efficiency, optical transparency and laser damage threshold
(LDT) in potassium dihydrogen phosphate (KDP) crystals grown by slow
evaporation solution technique (SEST) has been investigated. The influence of
doping on growth rate and morphology of the grown crystals has also been
studied. Powder X-ray diffraction data confirms the crystal structure of KDP
and shows a systematic variation in intensity of diffraction peaks in
correlation with morphology due to varying LT concentration. No extra phase
formation was observed which is further confirmed by Fourier Transform (FT)
Raman studies. High-resolution X-ray diffraction curves indicate that
crystalline perfection has been improved to a great extent at low
concentrations with a maximum perfection at 1 mol% doping. At higher
concentrations (5 to 10 mol%), it is slightly reduced due to excess
incorporation of dopants at the interstitial sites of the crystalline matrix.
LDT has been increased considerably with increase in doping concentration,
whereas SHG efficiency was found to be maximum at 1 mol% in correlation with
crystalline. The optical transparency for doped crystals has been increased as
compared to that of pure KDP with a maximum value at 1 mol% doping.
