Effect of Ni on the structural, optical, thermal and dielectric properties of ADP single crystals

The effects of the addition of Ni²⁺ on the growth and various properties of ammonium dihydrogen phosphate single crystals grown from aqueous solution by the slow evaporation method have been studied. The grown crystals were subjected to HRXRD, UV-Vis, TG/DTA and dielectric studies. The structural perfection of the grown crystal has been analyzed by high resolution X-ray diffraction rocking curve measurements. UV-Vis studies show that the grown crystal has good transparency in the entire visible region which is an essential requirement for a nonlinear crystal. Higher decomposition temperature was observed from TG/DTA. Dielectric constant and dielectric loss were measured for the grown crystal for different frequencies and temperatures.     

Investigation on structural,optical, thermal,mechanical and dielectric properties of l-proline cadmium chloride monohydrate single crystals: An efficient NLO material

In the present work, we have grown single crystals of l-proline cadmium chloride monohydrate (LPCCM) by slow evaporation solution technique (SEST) at room temperature and recorded their live growth kinetics with the help of inverted microscope. Crystal size at various stages of growth and its corresponding morphology was also recorded. Powder X-ray diffraction (PXRD) analysis of LPCCM single crystals confirmed the orthorhombic structure. Respective values of crystallite size, strain and dislocation density have been calculated using PXRD data. Metal complex coordination of the single crystal is studied by FTIR spectroscopic. The optical properties of the grown crystals were investigated through UV–VIS spectroscopic studies and shows that the crystals have very low absorption in entire characterized wavelength range 200–800 nm. The optical band gap was calculated and found to be ∼5.6 eV. Optical constants of the material is determined by theoretical calculations. The chemical etching study was also carried out to study the density of defects in the grown crystals. The photoluminous excitation and emission spectra and thermal property by TGA/DTA curve were recorded. Further, the mechanical properties have been studied using Vicker's microhardness tester as well as many parameters such as fracture toughness (K_c), Brittleness index (B_i) and yield strength (σ_ν) are presented. Dielectric studies have been carried out with varying frequency and temperatures.     

Influence of NH4Cl on the < 1 0 0> directed growth and properties of ADP crystal

Good quality, pure and ammonium chloride added < 1 0 0> directed ADP single crystals with different sizes were grown by Sankaranarayanan-Ramasamy method with the vision to improve the properties of the crystal. The grown crystals have cylindrical morphology and the crystals were subjected to UV-Vis., DTA, microhardness, laser damage threshold, dielectric, piezoelectric and SHG studies. The addition of ammonium chloride improves the quality and yields crystals with transparency more than 80% in minimum duration of growth. Higher laser damage threshold and mechanical stability were observed in ammonium chloride added ADP crystals. Low dielectric loss shows that the grown crystal contains minimum defects. Good piezoelectric behaviour was observed for the grown crystals. The SHG efficiency of the crystals was obtained using Nd-YAG laser, which is approximately 3 times that of pure ADP and shows the suitability of the ingot for nonlinear optical applications.     

Growth, thermal, dielectric and mechanical studies of triglycine zinc chloride, a semiorganic nonlinear optical material

Triglycine zinc chloride, a semiorganic material, has been grown by slow solvent evaporation technique from a mixture of aqueous solution of glycine and zinc chloride in 2:1 molar ratio at room temperature. The grown crystal is up to the dimension of 45 × 23 × 18 mm³. Characterization of the crystals was made using single-crystal X-ray diffraction for obtaining unit cell parameters. Powder X-ray diffraction was recorded and the major peaks were indexed. Simultaneous thermogravimetric analysis and differential thermal analysis were carried out for the as grown crystals to determine the thermal stability of the crystal. The crystals were further characterized by UV-Vis-NIR transmission spectrum in the range of 200 to 1100 nm. Dielectric constant and dielectric loss measurements were carried out at different temperatures and frequencies. Mechanical studies were carried out on the as grown crystal.     

Investigation of SR method grown 0 0 1 directed KDP single crystal and its characterization by high-resolution X-ray diffractometry (HRXRD), laser damage threshold, dielectric, thermal analysis, optical and hardness studies

0 0 1 directed potassium dihydrogen orthophosphate (KDP) single crystal was grown by Sankaranarayanan–Ramasamy (SR) method. The 0 0 1 oriented seed crystals were mounted at the bottom of the platform and the size of the crystals were 10 mm diameter, 110 mm height. Two different growths were tried, in one the crystal diameter was the ampoule's inner diameter and in the other the crystal thickness was less than the ampoule diameter. In the first case only the top four pyramidal faces were existing whereas in the second case the top four pyramidal faces and four prismatic faces were existing through out the growth. The crystals were grown using same stoichiometric solution. The results of the two growths are discussed in this paper. The grown crystals were characterized by high-resolution X-ray diffractometry (HRXRD), laser damage threshold, dielectric, thermal analysis, UV–vis spectroscopy and microhardness studies. The HRXRD analysis indicates that the crystalline perfection is excellent without having any very low angle internal structural grain boundaries. Laser damage threshold value has been determined using Nd:glass laser operating at 1054 nm. The damage threshold for the KDP crystal is greater than 4.55 GW cm⁻². The dielectric constant was higher and the dielectric loss was less in SR method grown crystal as against conventional method grown crystal. In thermal analysis, the starting of decomposition nature is similar in SR method grown KDP crystal and conventional method grown crystal. The SR method grown KDP has higher transmittance and higher hardness value compared to conventional method grown crystals.     

Optical,mechanical and transport properties of unidirectional grown l-tartaric acid bulk single crystal for non-linear optical application

Good optical quality bulk single crystal of l-tartaric acid has been grown by directional solidification crystal growth method from aqueous solution. Crystal of dimension 77 mm length and 12 mm diameter has been grown at a growth rate of 2.5 mm day⁻¹ which is the maximum size and growth rate achieved so far. The grown crystal was confirmed by powder XRD analysis and the presence of the functional groups in the crystal lattice was confirmed by Fourier transform infrared spectral analysis. Transmission spectral analysis shows that the crystal has more than 90% of transmittance in visible and near infrared region which exhibits the good optical quality of the crystal. The optical band gap was estimated to be 4.8 eV and it shows indirect optical transition. Thermal analysis shows the crystal to be thermally stable up to 172 °C and the load variation of the hardness has been explained on the basis of normal indentation size effect from microhardness study.     

Growth, structural, optical, thermal and mechanical properties of glycine zinc chloride single crystal

The nonlinear optical single crystals of glycine zinc chloride were grown by the slow cooling method from aqueous solution. The title compound was synthesized and purified by repeated recrystallization process. Grown crystals were characterized by X-ray diffraction, FT-IR and FT-Raman spectral analysis. The range and percentage of optical transmission were ascertained by recording UV-Vis-NIR spectrum. Thermal properties were investigated by DTA and TGA analyses. Its second harmonic generation relative efficiency was measured by Kurtz and Perry powder technique using Nd:YAG laser and was observed to be 0.5 times that of potassium dihydrogen orthophosphate. Its mechanical hardness was estimated by Vickers microhardness method.     

Structural,optical and dielectric studies of novel non-linear Bisglycine Lithium Nitrate piezoelectric single crystal

The novel non-linear semiorganic Bisglycine Lithium Nitrate (BGLiN) single crystals were grown by slow evaporation technique. The structural analysis revealed that it belongs to non-centrosymmetric orthorhombic structure. The presence of various functional groups in the grown crystal was confirmed by FTIR and Raman analysis. Surface morphology of the grown crystal was studied by scanning electron microscopy. The optical studies show that crystal has good transmittance (more than 80%) in the entire visible region and a wide band gap (5.17 eV). The optical constants such as extinction coefficient (K), the reflectance (R) and refractive index (n) as a function of photon energy were calculated from the optical measurements. With the help of these optical constants the electric susceptibility (χ_c) and both the real (ε_r) and imaginary (ε_i) parts of the dielectric constants were also calculated which are required to develop optoelectronic devices. In photoluminescence studies, a broad emission band centered at 404 nm was found in addition to a small band at 352 nm. A broad transition (from 29 to 33 °C) was observed with low dielectric constant value. A high piezoelectric charge coefficient (d₃₃) of 14 pC/N was measured at room temperature which implies its usefulness for various sensor applications. The second harmonic generation efficiency of crystal was found to be 1.5 times to that of KDP. From thermo gravimetric analysis and differential thermal analysis, thermal stability and melting point (246 °C) were investigated. The dielectric behavior, optical characterization, piezoelectric behavior and the non-linear optical properties of the Bisglycine Lithium Nitrate single crystals were reported for the first time which established the usefulness of these crystals for various piezo- and opto-electronics applications.     

Physicochemical properties of organic nonlinear optical crystal for frequency doubling: Glycine acetamide

Non-linear optical (NLO) crystal of glycine acetamide (GA) is synthesized and grown in aqueous solution by slow evaporation technique. The cell parameters of the grown crystal are identified from single crystal XRD and the functional groups are confirmed in vibrational analysis. Temperature dependence of the material is probed using TGA/DTA. Mechanical strength of the grown material is tested by Hardness studies. UV-VIS-NIR spectral study explains the transmission ability of the crystal in visible range also the photoluminescence spectrum explains the transition mechanism of ions. The NLO activity of the crystal is confirmed by Kurtz power technique.     

Growth and characterization of a new semi-organic nonlinear optical sodium paranitrophenolate paranitrophenol dihydrate single crystal

A new semi-organic nonlinear optical sodium paranitrophenolate paranitrophenol dihydrate single crystal is grown successfully using methanol as solvent by slow evaporation technique to dimensions of 14 × 5 × 4 mm³ in a period of 7 days. The grown crystal is characterized by X-ray diffractometry and UV-Visible spectral analysis. X-ray diffraction data reveals that the crystal belongs to monoclinic system with space group C2. Optical absorption studies illustrate low absorption in the entire UV and Visible region. The second harmonic generation (SHG) efficiency of the crystal measured by Kurtz's powder technique infers that the crystal has NLO coefficient 5 times greater than that of KDP crystal. Remarkable mechanical strength with the work hardening coefficient less than 2 and thermal stability up to 120 °C of the grown crystal is reported.     

Growth, thermal and mechanical properties of new nonlinear optical barium bis-paranitrophenolate paranitrophenol tetrahydrate single crystal

Barium bis paranitrophenolate paranitrophenol tetrahydrate, a new semiorganic nonlinear optical single crystal has been grown by slow evaporation solution growth technique at room temperature of 30 °C. Crystal of dimensions of 29 mm × 11 mm × 5 mm was obtained in a period of 30 days. X-ray diffraction analysis reveal the newness of the crystal structure belonging to the orthorhombic class with lattice parameters a = 19.899(5) Å, b = 28.019(8) Å, c = 10.745(4) Å and α = β = γ = 90°. The grown crystal is examined for its nonlinear optical nature with Kurtz powder technique after being sieved for particle sizes between 5 and 100 μm and analyzed for its thermal and mechanical properties. The effective nonlinear optical coefficient being 16 times greater than that of KDP crystal, good thermal stability up to 120 °C with the Meyer's constant n < 2 helps fashion the crystal towards device geometry.     

Third order optical non-linear (Z-scan), birefringence,photoluminescence, mechanical and etching studies on melaminium levulinate monohydrate (MLM) single crystal for optical device applications

Z-scan studies on the grown crystal was investigated by diode-pumped Nd; YAG laser. Nonlinear refractive index (n₂) and third-order nonlinear optical susceptibility (χ³) values of MLM were found to be −1.0 × 10⁻⁸ cm²/W and 1.36 × 10⁻⁶ esu respectively. Powder X-ray diffraction analysis depicted that the crystal belongs to monoclinic system with space group P2₁/c. Birefringence study revealed the optical dispersion behavior of MLM crystal. Linear refractive index on (10-1) plane was measured by prism coupling technique and was estimated to be 1.4705. Hardness study was carried out along three different planes which exhibit hardness anisotropy of 41.11%. Meyer's index values of the grown crystal for the (10-1), (010) and (111) planes were found to be 2.39, 2.61 and 2.04 respectively. Etching studies on the prominent (10-1) growth plane was explained by two dimensional layer growth mechanisms. Photoluminescence study was performed on MLM crystal to explore its efficacy towards optical device fabrications.     

Organic nonlinear optical crystal 4-hydroxy-N-methyl 4-stilbazolium besylate synthesis and characterization

Novel organic nonlinear optical material 4-hydroxy-N-methyl 4-stilbazolium besylate has been synthesized and 7 mm × 5 mm × 3 mm size crystals were grown by slow evaporation technique. Single crystal X-ray diffraction analysis reveals that the crystal lattice is monoclinic. From powder X-ray diffraction analysis the diffraction planes have been indexed. Fourier transform infrared spectrum for our sample confirms the presence of functional groups in the grown crystal. Second harmonic efficiency was determined using Kurtz powder method in comparison with urea to confirm the nonlinearity of the material. The results are discussed in detail.     

Studies on lithium l-ascorbate dihydrate: An interesting chiral nonlinear optical crystal

Lithium l-Ascorbate dihydrate (LLA) is a new metal organic nonlinear optical crystal belonging to the saccharide family. Single crystals of LLA were grown from aqueous solution. Solubility of the crystal has a positive temperature coefficient facilitating growth by slow cooling. Rietveld refinement was used to confirm the phase formation. The crystal has prismatic habit with (010), (001) and (10−1) prominent faces. Thermal analysis shows that the crystal is stable up to 102 °C. Transmission spectrum of the crystal extends from 302 nm to 1600 nm. Dielectric spectroscopic analysis revealed Cole–Cole behaviour and prominent piezoelectric resonance peaks were observed in the range of 100–200 kHz. Second harmonic generation (SHG) conversion efficiency of up to 2.56 times that of a phase matched KDP crystal was achieved when the (010) plate of LLA single crystal was rotated about the +ve c axis, by 9.4° in the clockwise direction. We also observed SHG conical sections which were attributed to noncollinear phase matching. The observation of the third conical section suggests very high birefringence and large nonlinear coefficients. A detailed study of surface laser damage showed that the crystal has high multiple damage thresholds of 9.7 GW cm⁻² and 4.2 GW cm⁻² at 1064 nm and 532 nm radiation respectively.     

Study of pure and l-tartaric acid doped ammonium dihydrogen phosphate single crystals: A novel nonlinear optical non-centrosymmetric crystal

Single crystals of pure and l-tartaric acid (LTA) C₄H₆O₆ doped ammonium dihydrogen phosphate (ADP) (NH₄) H₂PO₄ were grown by slow evaporation solution technique (SEST) at ambient conditions. Powder X-ray diffraction (PXRD) analysis was carried out to confirm the crystal structure and no additional phase was observed due to doping except a systematic variation in peak intensities. Fourier transform infrared spectral analysis was done to examine the presence of various functional groups in the grown crystals. UV–VIS–NIR spectroscopic analysis was carried out to see the change in optical transparency of pure ADP and crystals due to LTA with different doping concentrations. Second harmonic generation (SHG) efficiency measurement was done to examine the enhancement in the nonlinear optical characteristics of the grown crystals. The effect of LTA dopant on crystal morphology, thermal and mechanical properties of ADP have also been presented in this paper. The above studies reveal the effect of incorporation of LTA into the lattice of ADP crystals.     

Synthesis,crystal growth,structural, spectral,thermal, mechanical,linear and nonlinear optical studies of organic single crystal 4-Iodo 4-nitrostilbene (IONS): A potential NLO material

An organic nonlinear optical material 4-Iodo 4-nitrostilbene (IONS) has been synthesized and good optical quality single crystal was grown from ethyl methyl ketone solvent by the solution growth technique. Single and powder X-ray diffraction analyses reveals that the grown crystal belongs to monoclinic crystal system with noncentrosymmetric space group ‘P2₁’ and it has good crystalline nature. Functional groups and molecular structure of the title compound were confirmed by FTIR and ¹H NMR respectively. The UV–Vis–NIR absorption study reveals no absorption in the visible region and the cut-off wavelength was found to be at 412.84 nm, TG/DTA, mass spectral analysis, photoluminescence and microhardness studies have been carried out for the grown crystals and results are discussed in detail. The second harmonic efficiency of the IONS was determined by Kurtz–Perry powder technique which reveals that the IONS crystal (3.1 V) has greater efficiency i.e., 143 times to that of KDP (21.7 mV).     

Influence of defects on the quality and optical studies of sodium p-nitrophenolate dihydrate, a nonlinear optical material

Nonlinear optical material of sodium p-nitrophenolate dihydrate was synthesized by employing the technique of controlled evaporation and the effect of temperature on growth morphology was investigated. Single crystal XRD analysis confirms that the crystals with different morphologies have the same lattice parameters. The high-resolution X-ray diffraction curves recorded by a multicrystal X-ray diffractometer revealed the presence of very low angle tilt boundaries. The green emission band at 524 nm is due to the existence of defects on the crystal which corroborated with HRXRD studies. The wide band gap of the SPND crystals confirms the large transmittance in the visible region.     

Gamma irradiation effect on optical and dielectric properties of potassium dihydrogen phosphate crystals

The effect of Co⁶⁰ gamma-ray irradiation on potassium dihydrogen phosphate crystals is investigated at doses ranging from 1 kGy to 100 kGy with different diagnostics, including UV–Vis absorption spectroscopy, fluorescence spectroscopy, DC electrical conductivity, positron annihilation lifetime spectroscopy and Doppler-broadening spectroscopy. The optical absorption spectra show a wide absorption band between 250 and 400 nm after γ-irradiation and its intensity increases with the increasing irradiation dose. The simulation of radiation defects show that this absorption is assigned to the formation of substitutional impurity defects due to Al, Mg ions substituting for K ions. The fluorescence peak at 355 nm blue shifts after irradiation. The fluorescence intensity is observed to increase with the increasing irradiation dose. The positron annihilation lifetime spectroscopy is used to probe the evolution of vacancy-type defects in potassium dihydrogen phosphate crystal. The variation of size and concentration of vacancy-type defects with the different irradiation dose is investigated. The Doppler-broadening spectroscopy gives direct evidence of the formation of irradiation-induced defects. The dc electrical conductivity of γ-irradiated potassium dihydrogen phosphate crystals increases with the increasing irradiation dose when the dose is less than 10 kGy, whereas keeps constant at high irradiation dose of 100 kGy. The increase of electrical conductivity is associated with the increase of the proton defect concentration in the crystal. A possible explanation about the change of proton defect concentration with irradiation dose is presented.     

Improved nonvolatile holographic storage properties in Zr:Ru:Fe:LiNbO3 crystal by blue light recording

Lithium niobate crystal triply doped with zirconium, ruthenium and iron was grown by conventional Czochralski method and its nonvolatile storage characteristics were investigated by means of two-wavelength technology, where blue and red beam were used as recording and readout light, respectively. In oxidized Zr:Ru:Fe:liNbO₃ crystal, short response time of 9.1 s and high recording sensitivity of 0.92 cm/J were demonstrated, together with high fixed diffraction efficiency of 44.9% maintained. These excellent properties were attributed to the elimination of intrinsic defects by ZrO₂ doping and effective excitation of electrons by blue light. Our experimental results indicated this doped LiNbO₃ crystal was an outstanding medium for holographic storage applications.     

Theoretical investigations of optical properties of l-arginine trifluoroacetate crystal

In order to determine the molecular dipole moment (μ), polarizability (α), and first hyperpolarizability (β) of l-arginine trifluoroacetate (LATF) crystals, a series of basis sets including polarized and diffuse functions have been employed at the framework of Hartree–Fock and second order Möller–Plesset perturbation theory methods. The MP2/6-311++G(d,p) model predicts for the converged value of in-crystal dipole moment, polarizability and first hyperpolarizability are 21.2 D, 20.0 × 10⁻²⁴ esu and 50.0 × 10⁻³¹ esu, respectively. The calculated HOMO and LUMO energies show that charge transfer occur within the molecule. Electronic excitation properties are discussed within the framework of the two-level model on the basis of an orbital analysis. The coupled perturbed Hartree–Fock (CPHF) procedure yields information on the dispersion behavior of first hyperpolarizability terms. The magnitudes of the various hyperpolarizability terms which describe the various second-order nonlinear processes show the following trend: β(−2ω;ω,ω) > β(0;ω,−ω) > β(0,0,0). By using the molecular structures and the molecular first hyperpolarizability, the components of second harmonic tensor coefficient d of the crystals were evaluated by the oriented-gas model.