Development of wireless controller for ampoule translation and growth of organic nonlinear optical single crystals using vertical bridgman method

Abstract

Recent advancement in the field of science and technology has commercialised the technologically important nonlinear optical (NLO) devices for telecommunications, optical signal processing devices through optical phase conjugation, image processing, optical switching, optical data processing and frequency generation. The research on NLO crystals with high NLO response for device fabrication still remains a challenge. Among many materials, organic materials have greater advantages due to their large NLO coefficients and structural diversity or flexibility in nonlinear optics. On considering the lasers, the pulsed lasers and the continuous-wave lasers are being used widely in various fields. However, the drawback is that the lasers damage the sensor when they are exposed to their high intensities. Hence, the optical limiters are required to protect the sensors effectively. Organic crystals possessing good optical limiting values are used in a few applications like pulse shaping, smoothing and pulse compression. The centrosymmetric phase organic single crystals exhibit third-order nonlinear optical property, and therefore, have wider applications in optical technologies. Although, organic compounds like azobenzene, porphyrins, and liquid crystals are available, materials with stable and efficient optical limiting action at low intensities are yet to surface for such applications. Hence, in this present work, optically transparent, phenyl benzoate (PB), 3-Hydroxy-4-Methoxybenzaldehyde (3H4MB) and 2-Hydroxy-1- napthaldehyde (2H1N) single crystals were grown using single zone transparent Bridgman melt-growth furnace. Further, the grown crystals weresubjected to various characterisation techniques such as single crystal XRD, powder X-Ray diffraction, UV-Vis-NIR, Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA), Differential Scanning Analysis (DSC), Dielectric and third-order nonlinearity studies (Z-scan). The grown crystals were also tested for optical limiting behaviour studies. newline