Linear and nonlinear optical properties of L-phenylalaninium maleate a promising nonlinear optical single crystal

By S. Alfred Devaprasad and J. Madhavan

Single crystals of L-phenylalaninium maleate (LPM) were grown by slow solvent evaporation technique at room temperature. Good optical grade single crystals of size 10×4×3mm3 are obtained. The structure of the grown crystal was obtained from single crystal XRD. It is observed from the XRD data that LPM crystal belongs to monoclinic system with space group P21.  The Fourier transform infrared analysis (FT-IR) was carried out and the various functional groups in the sample were identified. The optical absorption spectrum of the sample was recorded in the range 200-2000 nm. The UV-Vis-NIR spectrum shows low absorption in the entire visible region. The second harmonic generation efficiency of the powdered sample was measured using Nd:YAG  Q-switched laser with first harmonic output of 1064 nm and KDP was taken as the reference material. The variation of dark current and photo current with the applied field was studied using a Keithly 480 picoammeter. Photoconductivity study confirms the negative photoconductive nature of LPM.

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