Growth of tetrakis thiourea potassium iodide as new second order optical material

A novel organometallic nonlinear optical (NLO) crystal, namely thiourea complex of tetrakis thiourea potassium iodide (TTPI), has been grown by slow evaporation solution growth technique. The harvested crystal is large in size. To our knowledge there is no report is available for the bulk size single crystal of TTPI. This material has a positive temperature coefficient and has been grown by slow evaporation solution growth technique. The grown crystal have been characterized by employing several techniques such as single crystal and powder X‐ray diffraction, FTIR, UV‐Vis‐NIR spectra, thermo gravimetric analyses respectively. Etching studies have also been carried out in order to know the surface defects on the as grown specimen of TTPI. The relative second harmonic generation efficiency have been tested by using Nd:YAG laser as source. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and high frequency dielectric study of pure and thiourea doped KDP crystals

Non linear optical (NLO) materials have acquired new significance with the advent of a large number of devices utilizing solid‐state laser sources. Several NLO materials have been used for this kind of technological applications. The Potassium di‐hydrogen phosphate (KDP) one of NLO material having superior non linear optical properties has been exploited for variety of applications. In the present investigation we have grown KDP crystals from aqous solution with thiourea, an organic non linear optical material. We could enhance the SHG efficiency of thiourea doped KDP crystal. It was 1.99 times more that of pure KDP. We observed more enhancements in nonlinearity for low concentration of thiourea.The crystal structure and cell parameters of grown crystal were determined from Powder XRD.The incorporation of thiourea in the grown crystals was qualitatively analyzed from FT‐IR study. The absorption spectra of pure and thiourea doped KDP crystal reveal that thiourea doped KDP crystals would be a better nonlinear optical (NLO) material for second harmonic generation (SHG) than pure KDP. The thermal decomposition and weight loss of pure and thiourea doped KDP crystal was observed by thermogravimetric (TGA) analysis and Differential Scanning Calorimetry (DSC). The high frequency dielectric study of pure KDP crystal, thiourea doped KDP crystals and organic additive thiourea was carried out using X‐band at frequency 8GHZ and 12GHZ by transmission line wave guide method. We observed low dielectric constant of thiourea doped KDP crystal when it is doped with 2mole% of thiourea. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of tris allylthiourea mercuric chloride crystals

Single crystals of tris allylthiourea mercury chloride (ATMC), a semi‐organic nonlinear optical material, have been grown from a low‐temperature solution growth technique by slow cooling method. In the present work, we have grown ATMC crystal which is a new nonlinear optical material (NLO) having high optical quality and its second harmonic generation (SHG) efficiency is thrice that of Urea. The grown crystals have also been subjected to various characterization studies like X‐ray diffraction, UV‐VIS, FT‐IR and TGA‐DTA. X‐ray powder diffraction study confirmed the crystal structure of ATMC, UV‐VIS /FT‐IR spectral analysis showed the crystal has good optical transmission in the entire visible region and TGA‐DTA studies showed the thermal properties and complex degradation of ATMC crystal. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure,spectroscopic studies and non‐linear optical properties of 2‐amino‐3‐nitropyridinium trichloroacetate

A new quadratic nonlinear optical crystal, 2‐amino‐3‐nitropyridinium trichloroacetate (2A3NPTCA), was synthesized and the single crystals were grown by slow evaporation method at room temperature. Single crystal X‐ray diffraction and powder X‐ray diffraction experiments were carried out in order to confirm the structure and crystalline nature of 2A3NPTCA crystal. The chemical bonding and various functional groups present in the 2A3NPTCA were identified from FT‐IR spectrum. The UV–visible–NIR transmission spectrum shows that it is suitable for frequency‐converting in the wavelength region of 431–1200 nm. Thermogravimetric (TG) and differential thermal analysis (DTA) were carried out to characterize the thermal behaviors of the grown crystals. Kurtz and Perry powder method for second harmonic generation (SHG) measurements demonstrate that 2A3NPTCA is a phase matching material and its nonlinear optical efficiency is two times that of KDP. All the above results suggest that 2A3NPTCA is a potential candidate of NLO material.     

Crystal growth,thermal, optical and microhardness studies of tris (thiourea) zinc sulphate - a semiorganic NLO material

Tris (thiourea) zinc sulphate (ZTS), a semiorganic nonlinear optical (NLO) material has been synthesized at 30 °C. The solubility was determined in different solvents such as water, ethanol and water mixture of ethanol (1:1). Good quality single crystals with size 10 × 8 × 6 mm³ were grown by slow evaporation technique within three weeks with approximate growth rate of 0.5 mm/day. The grown crystals have been subjected to single crystal X-ray diffraction to determine the unit cell dimensions and morphology. The TGA and DTA reveal that the material has good thermal stability. The UV-Vis spectrum shows that the material has wide optical transparency in the entire visible region. The second harmonic generation was confirmed by Kurtz powder method. The birefringence of the crystal was measured in the visible region and it was found to vary with the wavelength. The microhardness test was carried out in (100) plane and the load dependent hardness was measured. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structural,thermal, mechanical and z‐scan studies on 4‐nitrophenol single crystals

4‐nitrophenol (4‐NP) single crystals have been grown by using slow evaporation and slow cooling techniques. A single crystal with size in the range of 7x3.4x1.8cm³ has been obtained by slow cooling method. The grown crystals have been subjected to various characterization studies. The powder XRD spectrum of 4‐NP reveals the good crystalline nature of the grown crystal. Single crystal XRD studies show that the crystal belongs to monoclinic system with cell parameters of a=6.09 Å, b=8.79 Å, c=11.61 Å, α=γ=90°, β=103.15°. The resultant FTIR spectrum confirms the various functional groups present in 4‐NP. Thermal analysis has been performed on the material to study the thermal stability of 4‐NP. The grown crystals belong to the category of soft materials as confirmed by Vickers Hardness tests. The optical transmiitance of 4‐NP single crystals has been measured from Vis‐IR spectroscopy study. The nonlinear optical properties have been analyzed by z‐scan technique and 4‐NP is found to be self defocusing because of its negative nonlinear refractive index. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and Characterization of a New Nonlinear Optical Crystal: Bis Thiourea Zinc Chloride

Bis Thiourea Zinc Chloride (BTZC) a new semiorganic nonlinear optical material has been synthesized. The solubility studies have been carried out in the temperature range 30°‐ 55°C. Single crystals of BTZC have been grown by slow evaporation of saturated aqueous solution at room temperature. The lattice parameters of the grown crystals have been determined by single crystal X‐ray diffraction technique. The UV‐Vis‐NIR transmittance spectrum has been recorded in the range 200‐2000 nm. The FT‐IR spectrum has been recorded in the range 400‐4000 cm^‐1 and the spectral bands have been compared with similar thiourea complexes.     

Growth and characterization of organic nonlinear optical material: Benzilic acid

The organic nonlinear optical crystals of benzilic acid were grown by the slow evaporation method using ethanol as a solvent. Single-crystal X-ray diffraction (XRD), powder XRD studies and Fourier transform infrared (FTIR) spectral analysis were carried out to confirm the benzilic acid crystal. The optical transparency was studied by ultra violet (UV)–visible spectral analysis. Thermal properties of the grown crystals were studied by thermogravimetric and differential thermal analyses. The melting point of the grown crystal was confirmed by differential scanning calorimetry (DSC) analysis. The second harmonic generation (SHG) efficiency was found to be 2 times that of KDP.     

Growth,optical and thermal studies of nonlinear optical L‐arginine perchlorate single crystals

A potentially useful semiorganic nonlinear optical (NLO) material, L‐arginine perchlorate, has been synthesized and bulk crystals have been grown by slow cooling technique. The grown crystals were characterized by single crystal X‐ray diffraction, UV‐Vis‐NIR spectroscopy, FT‐IR, thermal analysis and SHG measurements. The grown crystals were thermally stable upto 153°C and exhibit SHG efficiency of about 0.17 with respect of Urea. The etching studies have been carried out on the grown crystal. LAPC has good optical transmission not only in the visible range, however, also in the near UV part of the spectra and hence it is a potential material for nonlinear frequency conversion. The refractive index was measured by the Brewster's angle method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Nucleation kinetics and growth of nonlinear optical bis (dimethyl sulfoxide) manganese mercury thiocyanate single crystals

Nonlinear optical (NLO) material of bis (dimethyl sulfoxide) manganese mercury thiocyanate (MMTD) was synthesized by two step reaction method. The solubility and metastable zonewidth were experimentally determined in order to optimize the growth parameters. Bulk crystals of MMTD were grown by slow cooling and slow evaporation methods. The structure of the grown crystal was confirmed by X‐ray diffraction analysis. Presence of functional groups and the coordination of Lewis base ligand of dimethyl sulfoxide (DMSO) were confirmed by FT‐IR analysis. Optical transparency of the grown crystals was studied by UV‐Vis spectroscopy. Nonlinear optical property of the grown crystal was confirmed by Kurtz powder method. Etching studies reveal the formation of triangular hillock etch patterns, indicative of 2D nucleation mechanism. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Nucleation, growth and characterization of L-tartaric acid—nicotinamide NLO crystals

The solubility, metastable zone width and nucleation parameters of organic nonlinear optical material L-tartaric acid–nicotinamide (LTN) have been determined. The crystals of LTN are grown by the slow cooling method. The grown crystals are morphologically interpreted. The crystalline powder of the grown crystals has been examined by X-ray diffraction and thermogravimetric analysis. The different modes of vibrations present in the crystal are identified by the Fourier infrared spectroscopy analysis. The powder SHG efficiency of LTN is comparable with that of KDP.     

Investigations on the growth,optical behaviour and factor group of an NLO crystal: L‐alanine alaninium nitrate

Amino acid family crystals exhibit excellent nonlinear and electro‐optical properties. L‐alanine alaninium nitrate (LAAN) single crystal belonging to the amino acid group was grown by slow cooling solution growth technique. The High resolution X‐ray diffraction (HRXRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, UV‐Vis., Photoluminescence (PL) and Factor group analyses were carried out. The factor group analysis reveals 183 internal vibrations for the title compound. The second harmonic generation property was tested by Kurtz‐Perry powder technique. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,growth and characterization of single crystals of pure and thiourea doped L‐glutamic acid hydrochloride

L(+)Glutamic acid hydrochloride [HOOC (CH₂)₂CH(NH₂) COOH·HCl], a monoamino dicarboxylic acid salt of L‐Glutamic acid was synthesized and the synthesis was confirmed by FTIR analysis. Solubility of the material in water was determined. Pure and Thiourea doped L‐Glutamic acid hydrochloride crystals were grown by low temperature solution growth using solvent evaporation technique. XRD, UV‐Vis‐NIR analyses were carried out for both pure and thiourea doped crystals. The crystals were qualitatively analyzed by EDAX analysis and the presence of thiourea was confirmed. The cell parameters of L‐Glutamic acid hydrochloride have been determined as a = 5.151 Å, b = 11.79 Å, c = 13.35 Å by X‐ray diffraction analysis and it crystallizes in orthorhombic space group P2₁2₁2₁. UV‐Vis‐NIR spectra analysis showed good optical transmission in the entire visible region for both pure and doped crystals. Micro hardness of both pure and doped crystals has been determined using Vickers micro hardness tester. The SHG efficiencies of both pure and doped crystals were determined using Kurtz powder test and pure L‐Glutamic acid hydrochloride crystal was found to possess better efficiency than thiourea doped L‐Glutamic acid hydrochloride crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structural,thermal and optical characterizations of a NLO material: L‐alaninium oxalate

An organic electro‐optic and nonlinear optical (NLO) material, L‐alaninium oxalate, was synthesized by the standard method. The synthesized material was purified by repeated recrystallization. Single crystals were grown by the slow evaporation technique. The grown crystals were transparent and had optimum dimensions (20 × 3 × 2 mm³) and were characterized by single crystal XRD, FT‐NMR, FT‐IR, TGA‐DTA and UV‐Vis‐NIR techniques. The second harmonic generation (SHG) from the material was confirmed using Nd:YAG laser. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of L‐lysine monohydrochloride dihydrate (L‐LMHCl) single crystal

A nonlinear optical crystal of L‐lysine monohydrochloride dihydrate (L‐LMHCl) was grown by slow evaporation solution growth technique using deionised water and mixed solvents of deionised water and ethanol. The functional groups and vibrational frequencies were identified using FTIR and FT‐RAMAN spectra analyses. Also, the presence of hydrogen and carbon atoms in the grown sample was confirmed using proton and carbon NMR spectra analyses. Using TG‐DTA analyses, the decomposition temperature was obtained. Transmittance of the grown crystals was analysed using UV‐visible spectrum. The mechanical strength of the grown crystals was found using Vicker's microhardness tester. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Nucleation kinetics and growth aspects of organic nonlinear optical L‐arginine trifluoroacetate single crystals

Experimental determination of solubility, metastable zonewidth and induction period for an organic nonlinear optical (NLO) L‐arginine trifluoroacetate (LATF) crystal is reported. The interfacial tension for different supersaturation conditions has been estimated for the LATF solution at 45°C. Bulk crystal of dimensions 57x5x3 mm³ has been grown by temperature lowering technique using optimized growth parameters. Powder X‐ray diffraction and FTIR studies confirm the crystalline nature and the functional groups of the grown crystals respectively. Linear optical property of the grown crystal has been studied by UV‐Vis spectrum. Thermal analyses have revealed that the compound is thermally stable upto 212°C. Kurtz powder SHG test confirm the nonlinear optical properties of the as‐grown LATF crystal. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Optical and microhardness studies of semiorganic nonlinear optical material: L‐ histidine tetrafluoroborate

L‐histidine tetrafluoroborate (L‐HFB) a semiorganic nonlinear optical material has been synthesized in aqueous solution at 50°C and characterized by FT‐IR and FT‐Raman spectroscopy studies. The solubility was determined in different solvents such as water, methanol and water mixture of methanol. The single crystals with dimensions 15x12x3 mm³ were grown by slow evaporation method within four weeks with approximate growth rate of 0.25 mm/day. The grown crystals have been subjected to single crystal X‐ray diffraction studies to determine the unit cell dimensions and morphology. The Kurtz powder second harmonic generation test shows that the compound is a potential candidate for frequency conversion. The refractive index has been measured using He‐Ne laser. The microhardness test was carried out and the load dependence hardness was observed. The material has a wide transparency in the entire visible region. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Single crystal growth and properties of semiorganic nonlinear optical L‐arginine hydrochloride monohydrate crystals

L‐arginine hydrochloride monohydrate (LAHCl.H₂O) has been synthesized and single crystals have been grown from its aqueous solution by slow evaporation and slow cooling methods. The solubility of the material was measured at various temperatures and bulk crystals of size 26×13×11 mm³ have been grown by optimizing the growth parameters. The grown crystals have been subjected to single crystal XRD studies to confirm the structure and to estimate the lattice parameters. FTIR analysis indicate the mode of vibrations of different molecular groups present in LAHCl and confirm the protonation of guanidyl, amino groups and deprotonation of COO^‐ groups. UV‐Vis transmission spectrum revealed the linear optical properties of the grown crystals with a transparency of 65% over the entire visible range upto 300 nm. Thermal behavior of the grown crystal was investigated from DTA and TGA measurements. Dielectric studies have been carried out on the grown crystals. Kurtz and Perry powder SHG technique confirms the NLO property of the grown crystal. The SHG efficiency of LAHCl was found to be 0.38 with respect to KDP. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Dielectric studies of metal complexes of thiourea crystals for electro‐optic modulation

In the present study three crystals of thiourea family viz. Zinc Thiourea Chloride (ZTC), Zinc Thiourea Sulfate (ZTS) and Bisthiourea Cadmium Chloride (BTCC) were grown from aqueous solution by slow evaporation technique. The grown crystals were studied by powder XRD, FT‐IR and UV‐visible. The dielectric study of grown crystals was carried out in X‐band using transmission line wave guide method. It was found that the BTCC has lowest dielectric constant among three metal complexes of thiourea crystals (ZTC, ZTS and BTCC), therefore it can be used for high speed electro‐optic modulation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Optical and mechanical properties of a new second order nonlinear optical crystal urea l‐threonine

A new second order non‐linear optical organic crystal Urea L‐threonine has been grown by aqueous solution slow cooling technique. The grown crystal is non hygroscopic and transparent in the visible region. The solubility of the grown crystal was found. The crystal structure and perfection were determined using powder XRD and High resolution XRD. The molecular structure was confirmed by ¹H‐NMR spectrum. Thermal properties of the crystal have been studied using thermogravimetric (TG) and differential thermal analysis (DTA). The dielectric response of the crystal with varying frequencies at different temperatures was studied. UV‐Visible spectrum was recorded to study the optical transparency of the grown crystals. The second order non linear optical property was examined by Kurtz powder technique and found that the second order susceptibilities is 1.2 KDP at wavelength 1064 nm. The mechanical behaviour was studied by Vickers Microhardness test. The results are discussed in detail. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)