Single crystals of vanillin were grown by the solution growth method using methanol as a solvent. Crystal up to the size of 1´0.6´1.4cm3 were grown for optical characterization. Optical quality of crystal was observed to be good. Vanillin has a higher figure of merit when compared to other crystals suitable for non-linear optical applications in the visible to near-infrared region. The crystal structure was studied by X-ray diffraction. The UV–Visual absorption spectra indicate a good transparency between 200 and 800 nm. The nonlinear refractive index 2 n and susceptibility (3) c have been measured through the Z-scan technique. Vanillin exhibits saturation absorption and self-focusing performance. Non-linear absorption Co-efficient b is determined as 7.6518´10-4 cm /W . Non-linear refractive index 2 n measured at the wavelength of 632.8 nm is calculated as 1.6369´10-8 cm2 /W . The real and imaginary parts of (3) c have been measured at 632.8 nm and were found to be 1.1915´10-7 esu and 2.8062´10-6 esu respectively. Also, the absolute value of the third order Non-linear optical susceptibility (3) c is 2.8088´10-6 esu .
