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A novel semiorganic nonlinear optical (NLO) crystal, bis(thiourea) barium nitrate (BTBN) was synthesized and grown by slow evaporation method. Structure of the new crystalline compound was confirmed by single crystal X-ray diffraction analysis and it showed that BTBN belongs to orthorhombic crystal system. The crystalline nature of the BTBN was confirmed by powder X-ray diffraction study. Important functional groups of BTBN were identified by FT-IR spectroscopic analysis. UV-Vis-NIR spectral study showed that the grown crystal is transparent in the entire visible region with low cut off wavelength of 304 nm. BTBN exhibits a SHG efficiency which is nearly 2.38 times higher than that of KDP. The BTBN crystal has high mechanical strength and belongs to soft category, which was confirmed by micorhardness study. The thermal stability of BTBN was determined from TGA and DTA thermal study which revealed that the BTBN crystal has thermal stability up to 243.1 °C. The surface properties and presence of elements was analyzed by SEM and EDAX study, respectively.

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Development of simple UV detection system using CdTe quantum dots (QDs) as primary detector with scintillating property on exposure to UV rays is reported. CdTe, CdTe/ZnS and CdTe/CdS QDs were synthesized in aqueous phase using mercaptosuccinic acid (MSA) as a capping agent and studied for its properties like crystallite size, band gap energy, fluorescence emission intensity and uniformity in size distribution. The prepared QDs were exposed to different radiations such as infrared (IR), ultraviolet (UV) and X-rays. The fluorescent emission was recorded by an optoelectronic circuit in terms of electrical signal. The result of this study shows that CdTe/ZnS QDs is better suited for the detection and measurement of UV rays. Hence these QDs could be used as a sensing element while fabricating nanosensor for UV detection.

A new inorganic nonlinear optical single crystal of sodium cadmium tetra chloride (SCTC) is successfully grown from aqueous solution by the slow evaporation technique at room temperature. The crystalline nature of the grown crystal is analyzed by powder X‐ray diffraction. The lattice parameters and crystal system is confirmed by single crystal X‐ray diffraction. Optical transmission study on SCTC crystal shows high transmittance in the entire UV–Vis region. The mechanical strength of the grown crystal is estimated by Vicker's microhardness test. The second harmonic generation (SHG) efficiency of the crystal is measured by Kurtz's powder technique infers that the crystal has nonlinear optical (NLO) efficiency 1.75 times that of KDP. The variation of dielectric constant and dielectric loss as a function of log frequency at various temperature reveals that the crystal shows normal dielectric behaviour. The growth process of SCTC crystal is analysed by etching study. The features of surface of grown crystal is analysed by SEM/EDAX spectrum. The third order nonlinear optical property is investigated for the grown crystal by z – scan technique and the results indicates that SCTC crystal should be a promising material for nonlinear optical device applications.

Nowadays, NLO materials are of current research interest due to their variety of applications such as second harmonic generation, optical bi-stability, laser remote sensing, optical disk data storage, laser driver fusion, medical and spectroscopic laser, photonic integrated circuitry, optical parametric oscillations and THz wave generation. This work concentrated on (bis)thiourea ammonium nitrate (BTAN) crystal was grown from aqueous solution by slow evaporation technique. The grown crystal has been subjected to single crystal X-ray diffraction to determine the unit cell dimensions. The grown crystal was also characterized by recording the powder X-ray diffraction patterns and by identifying the diffracting planes. The Fourier Transform Infrared (FT-IR) spectra have been recorded in the range 400–4500 cm-1. Second harmonic generation (SHG) for the materials of this work was confirmed using Nd:YAG laser. The UV–visible spectra show that the grown crystals have wide optical transparency in the entire visible region. The Thermo gravimetric/Differential Thermal Analyses reveal that the materials have good thermal stability.

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