Thermal and optical properties of new organic nonlinear optical single crystals

Abstract

Nonlinear optical (NLO) materials are useful in a number of industrial applications. Organic NLO single crystals of 3-(4-chlorophenyl)-1-(pyridin-3-yl) prop-2-en-1-one (4-Chloro chalcone, 4CC) and 3-(4-bromophenyl)-1-(pyridin-3-yl) prop-2-en-1-one (4-bromo chalcone, 4BC), having large second harmonic generation efficiency (SHG), were grown by slow evaporation technique. The thermal analysis reveals that these chalcone derivatives possess better thermal stability in comparison with urea. Both the crystals 4CC and 4BC are non-linear optically active with SHG efficiencies of 4 and 1.4 times that of urea respectively. The UV-Visible spectrum reveals that the crystals are transparent in the entire visible region. The substitution of a chloro group at the para position of the phenylene moiety is better in increasing the SHG efficiency of the crystal compared to a bromo group. Good thermal stability, optical transparency and SHG response make the crystals useful for frequency doubling of diode laser down to 435nm.