Organic materials are expected to have relatively strong
nonlinear optical properties due to delocalized electrons at
* orbitals. This expectation explains extensive search for better NLO materials among organic crystals.
L-arginine maleate dihydrate
L-arginine is one of the essential
amino acids
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
widely distributed in biological substances. It forms a number of salts with organic and inorganic acids showing non-linear optical properties. L-Arginine maleate dihydrate (C
6H
14N
4O
2,C
4H
4O
4,2H
2O) is one of these L-arginine salts which is a complex of strongly basic amino acid, carboxylic acid and provides useful information in relation to molecular interaction in present-day biological systems and to prebiotic self-organisms. It is also a nonlinear optical material with second harmonic generation efficiency 1.68 times that of KDP. L-arginine maleate dihydrate crystals are grown from solution by solvent evaporation; they belong to the triclinic space group P1.
L-methionine L-methioninium hydrogen maleate
L-methionine L-methioninium hydrogen maleate also belongs to the
amino acid family. Crystals are grown by slow evaporation of an aqueous solution containing L-methionine and
maleic acid, resulting in centimeter-large crystals of a non-centrosymmetric space group.
They were applied for
second-harmonic generation of an
Nd:YAG laser (wavelength 1064 nm), and SHG efficiency equal to that of KDP has been obtained.
References
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Nonlinear optical materials