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Chapter VI UV-Vis Spectroscopic….
6.5 Study of Pure and Amino acids Doped KDP Crystals
Various techniques have been employed to study the non linear optical
behavior of KDP crystals. Ganeev et al [30] studied the third order
susceptibilities (3) and the non linear refractive indices (n2) of KDP at wave
lengths 1064 nm and 532 nm by Z-scan technique. The measurements were
carried out at different pulse energies, focusing conditions and crystal lengths.
It was shown by the authors that the increase of phase matching angle leads
to decreasing of (3) of KDP crystals. Also, the self and gross-phase-
modulation coefficients in KDP crystals were measured by the Z-scan
technique by Zheng and Meyerhofer [31]. However, in the present
investigation the author has employed Kurtz powder technique to evaluate the
SHG efficiency, as this technique is quite rapid and does not need large single
crystal specifically cut and oriented in the proper direction. The effect of
doping of amino acids such as, L-glutamic acid, L-valine, L-histidine [32], L-
arginine, L-histidine and glycine [33] in KDP crystals have been reported
earlier.
Amino acids contain both a carboxyl group (COOH) and an amino
group (NH2). The general formula for an amino acid is given below in figure
(6.4).
Figure:6.4 General formula for an amino acid.
Although the neutrally-charged structure is commonly written, it is inaccurate
because the acidic COOH and basic NH2 groups react with one another to
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