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Good-quality organic nonlinear single crystal of 2,3-dimethyl-N-[(E)-2,4,5-trimethoxy benzylidene] aniline (DTA) was synthesized and successfully grown at room temperature by adapting slow evaporation technique using mixed solvent of acetone and methanol. The crystal structure was experimentally confirmed by single-crystal X-ray diffraction, where the DTA crystals crystallize in the centric space group (P $$\overline{1}$$ ) with triclinic crystal system. The surface morphology of DTA was examined by the Field Emission Scanning Electron Microscope (FE-SEM) technique. The presence of various modes of functional groups of the title crystal was analyzed by Fourier-Transform Infra-Red (FT-IR) spectra. Ultraviolet–Visible-Near Infrared (UV–Vis–NIR) spectrum showed high optical transparency of ~ 88% in the Vis and NIR region with a UV–Vis absorption edge of 390 nm. The result of photoluminescence studies suggests that the DTA crystal can be used as source material to exhibit green emission light. From thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, the melting point of the grown crystal was found to be 111 °C. The standard Z-Scan technique was employed to evaluate the third-order nonlinear optical properties of the DTA crystal. The obtained third-order nonlinear parameters were compared with few of the already reported NLO crystals. All these findings indicate that the title crystal may be an attractive material for nonlinear optical device applications.

Diphenylacetylene (DPAC) is a promising organic scintillator material for fast neutron detection. Solubility measurement was carried with two different solvents such as toluene and methanol. Stilbene mixed diphenylacetylene (DPACS) was successfully harvested from toluene with the dimensions of 42 × 12 × 8 mm3. X-ray diffraction confirms the monoclinic crystal structure with the obtained lattice parameters. The vibrational characteristic functional group was identified by FTIR studies. UV–Vis spectral analysis of the grown DPACS crystal reveals good optical transparency in visible and near IR region. The thermal behaviour and melting point of the sample was analysed by TGA-DSC. Chemical etching analysis was carried out on the crystal surface at an ambient temperature to see the dislocations and growth pattern of the crystal. Fluorescence broad emission peak was observed and the prompt and delayed fluorescence lifetimes of the DPACS were calculated.

Single crystals of Sm0.55Sr0.45Mn0.4Fe0.6O3were grown by an optical floating zone technique in an oxygen atmosphere. The powder X-ray diffraction pattern for the grown crystal revealed single-crystalline nature. The lattice parameters and atomic structure were refined and indexed using a General Structure Analysis System (GSAS) to an orthorhombic structure with lattice parametersa= 5.4415 (32) Å,b= 7.6994 (27) Å,c= 5.43868 (28) Å, and space group Pnma.

2-(2-Chloro-benzylidene)-Cyclododecanone, a cyclic ketone has been synthesized by direct aldol condensation reaction and the single crystals were grown in mixed solved (Tetrahydrofuran and ethanol) by slow evaporation method. The linear optical property of the crystal has been studied in the wavelength range 190 nm–1100 nm and optical constants were calculated theoretically. The saturation absorption and self-defocusing effect were observed in Z-scan technique. The magnitude of nonlinear refractive index (10−10 m2/W), nonlinear absorption (10−3 m/W) and third order nonlinear susceptibility (10−4 esu) has been calculated. The optical response time of the crystal is coming around 10−3 s.

Ammonium dihydrogen phosphate (ADP) is an important nonlinear optical (NLO) material used for electro-optical applications and finds various NLO applications using Nd:YAG and Nd:YLF Lasers. The Amino acids have properties like molecular chirality and zwitter ionic nature helps to improve NLO properties of ADP. The pure and l-threonine doped ADP crystals are grown using slow solvent evaporation technique at room temperature. The Powder XRD spectra suggest tetragonal crystal system and slight shifting of peak. The FT-IR spectra verify the presence of various functional groups of pure and doped ADP crystals. The FT-Raman shows strong absorption peak at 922 cm−1 due to asymmetric stretching of PO43− for all samples without shifting indicating the single phase nature of all samples. The photoluminescence study suggests the presence of defects in doped samples compared to the pure one due to increase of Stokes shift and vibrational energy relaxation phenomena. The presences of constituent elements are indentified using CHN analysis. The optical transmittance, energy band gap, skin depth, refractive index and extinction coefficient is study using UV–Visible spectroscopy and the dispersive behaviour of refractive index below absorption edge is study using Wemple-DiDomenico single oscillator model. The variation of capacitance and conductance is study using complex admittance spectroscopy. All the grown crystals have possessed negative photoconductivity. The second and third harmonic generation efficiency is increased nearly to double for l-threonine doped ADP crystals compared to pure Potassium dihydrogen phosphate (KDP). The laser damage threshold is measure for pure and doped ADP crystals. Keywords: ADP, Vibrational energy relaxation, Stoke shift, Wemple-DiDomenico single oscillator model, Z-scan, Complex admittance

To doubling the frequency of Nd: YAG and Nd: YLF laser sources the ammonium dihydrogen phosphate (ADP) single crystal is widely used. In the present communication, the effect of amino acid namely as l-serine on the growth and properties of ADP crystal is been reported. The slow solvent evaporation technique is adopted to grow pure and different weight percentage i.e. 0.4 wt%, 0.6 wt% and 0.8 wt% l-serine doped ADP crystals. The structural study suggested tetragonal structure symmetry of all grown crystal with single phasic nature of all of them. The amino acid dopant alters the functional group vibrations of ADP crystal as suggested in FT-IR spectroscopy. The change in morphology and presence of various elements is observed in SEM and EDAX spectroscopy. The improvement is observed in various optical properties like energy band gap, skin depth, SHG, third order nonlinear susceptibility, laser damage threshold etc. on doping the l-serine in ADP crystal. The spectra variation of refractive index of all grown crystals is studied. The pure and l-serine doped ADP crystals have posses negative kind of photoconductivity.

Pure and picric acid-added KDP (potassium dihydrogen phosphate) crystals are grown by slow evaporation technique from aqueous solution. Unit cell parameters for pure and doped KDP crystals were measured from single-crystal X-ray diffraction studies. Vickers and Knoop microhardness studies were carried out on the grown crystals over a load range of 0.1 to 0.5 N. The microhardness decreases with load P, i.e., normal indentation size effect (ISE), and from Meyers index it is shown that grown crystals falls in to hard material category. Mechanical properties, such as Young’s modulus, yield strength, elastic stiffness constant, were calculated for pure and doped KDP crystals. Hardness anisotropy has been observed in accordance with the orientation of the crystal. Etching studies were carried out using aqueous solution as an etchant. Improved second-harmonic generation efficiency is observed for doped KDP crystals in comparison to pure KDP crystals.

The pure and 0.1 wt% dl-methionine doped ADP crystals are grown using slow solvent evaporation technique at room temperature. The powder XRD study shows single phase nature of both grown crystals with tetragonal structural symmetry. The UV–Vis transmittance spectroscopy shows improvement in optical transmittance, energy band, and low refractive index of doped ADP crystal compare to pure ADP crystal. The Wemple–DiDomenico single oscillator model is found to be appropriate for the refractive index dispersion below the energy band edge of ADP crystal. The Nyquist plots of pure and doped ADP crystals represent presence of grain and grain boundary. The Jonscher’s powder law is successfully applied to the conductivity phenomena in pure and doped ADP crystals. The complex modulus spectroscopy helps to discriminate the grain and grain boundary in grown crystals clearly. The Non-Debye type relaxation is observed in both crystals. The nonlinear optical properties such as second harmonic generation efficiency and third order susceptibility are improved on doping the dl-methionine in ADP crystal.

Good quality, third order nonlinear optical single crystal, 2-(4-ethylbenzylidene) malononitrile (EBM) was successfully grown by slow evaporation solution growth technique (SESGT) at room temperature using ethanol solvent. The formation of new crystalline structure, packing array and features of the molecular geometry were confirmed through the single crystal X-ray diffraction analysis. And also, it is addressed that, crystal belongs to the monoclinic system with centrosymmetric space group P21/c. The morphology of the EBM crystal is simulated with the help of WinXMorph software. The crystalline purity and multifarious functional groups of the EBM were ascertained by powder XRD and FT-IR analyzes, respectively. The Uv–Vis–NIR spectral study directs the way to find the lower cut-off wavelength (λ = 427 nm) and transparency (∼76%) of the grown specimen. The band gap of the EBM is estimated to be 2.92 eV. The photoluminescence spectrum of the crystal reveals that, it can be served as a new green lighting material. The quite low dielectric responses of EBM play a noticeable role in micro-electronics device application. The low etch pit density (EPD) is great evidence for the crystalline perfection of the titular crystal. The laser induced surface damaged threshold (LDT) value of inclusion free EBM crystal is 2.11 GW cm-2, it is quite good as compared with previously reported crystals. The effective third order optical nonlinearity of the title crystal has been investigated systematically using typical Z-scan technique. All these findings are addressed to the EBM crystal which is smart candidate for the NLO applications.

Hybrid inorganic nonlinear optical crystals find huge applications in laser assisted photonic devices therefore present communication firstly aims to investigate the dielectric, microscopic and linear-nonlinear optical properties of ammonium zinc sulphate hydrate (AZSH) crystal. The inorganic AZSH complex has been synthesized and 15 × 10 × 09 mm3 single crystal was grown by slow solvent evaporation method. The powder and single crystal X-ray diffraction technique has been employed to evaluate the crystalline phase and determine the structural parameters of AZSH crystal. The optical transparency of AZSH crystal has been examined within the wavelength rage of 200–1100 nm. The enhanced second harmonic generation efficiency of AZSH crystal is 2.53 times higher than standard KDP crystal. The laser damage threshold of AZSH crystal has been determined using the Nd:YAG laser operating at 1064 nm. The close and open aperture Z-scan studies have been performed to ascertain the nature of third order nonlinear optical (TONLO) refraction and absorption of AZSH crystal. The order of TONLO parameters n2, β and χ3 is found to be 10−9 cm2/W, 10−4 cm/W, 10−4 esu respectively. The AZSH crystal is found to have violet colored luminescence emission centered at 370 nm. The dielectric constant and dielectric loss of AZSH crystal has been evaluated within 30 Hz to 1 MHz. The chemical etching technique has been imposed to examine the growth habitat and determine the etch pit density of AZSH crystal.

4-N,N-dimethylamino-4′-N′-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) terahertz organic material has been synthesized by the knoevenagel condensation method. DSTMS single crystals were grown in methanol by slow-cooling method. The linear optical property of DSTMS crystal has been studied using UV–Vis-NIR spectroscopy in the wavelength range 190–1100 nm and optical constants are calculated theoretically. The magnitude of nonlinear refractive index (10−10 m2/W), nonlinear absorption (10−3 m/W) and third order nonlinear susceptibility (10−4 esu) has been studied using Z-scan technique. Dielectric property of DSTMS crystal has been studied at frequency range 50 Hz–5 MHz. The electronic properties such as valence electron plasma energy, penn gap, fermi energy, electronic polarization, electric susceptibility of the grown crystal has been studied. Photoluminescence spectrum was recorded using xenon lamp in the range of 450–700 nm. Laser optical damage threshold of DSTMS crystal was calculated (3.57 GW/cm2) using pulsed Nd-YAG laser (1064 nm) of repetition rate 10 ns. The refractive index of the crystal (1.571) has been measured using Abbe’s Refractometer. The optical limiting behaviour of DSTMS crystal has been studied using Nd-YAG laser. The response time (τ) of optical limiting power for the crystals is 10−11 s.

The search for organic crystals with high efficient fast neutron detection with short decay time have become more demand nowadays. These are being used in the frontline areas in radiation medicine, neutron spectroscopy and special nuclear material detection. We explored the growth progress and characterized the pure and stilbene doped bibenzyl (BBS) organic scintillator crystal by solution growth technique. The solubility of bibenzyl was determined in methanol by thermogravimetric method. The grown crystal was subjected to single X-ray diffraction to find the cell parameters which shows the monoclinic structure. The crystallinity was examined by powder X-ray diffraction pattern. Fourier transform infrared spectra was carried out for the doped crystal and compared that of pure bibenzyl (BB) crystal. The absorption and transmittance range were measured by UV-Vis-NIR analysis. The emission spectrum was measured by photoluminescence, two significant peaks were observed at 353 and 373 nm. The grown BBS crystal decay time 0.8 and 1.65 ns was calculated for prompt and delayed emission by using pulsed nano-LED source. Thermal steadiness of BBS was verified by thermo-gravimetric and differential scanning calorimetry.

2-(4-fluorobenzylidene) malononitrile (FBM), an organic third order nonlinear (TONLO) single crystal with the dimensions of 32 × 7 × 11 mm3, has been successfully grown in acetone solution by slow evaporation technique at 35 °C. The crystal system (triclinic), space group (P-1) and crystalline purity of the titular crystal were measured by single crystal and powder X-ray diffraction, respectively. The molecular weight and the multiple functional groups of the FBM material were confirmed through the mass and FT-IR spectral analysis. UV–Vis–NIR spectral study enroles that the FBM crystal exhibits excellent transparency (83%) in the entire visible and near infra-red region with a wide bandgap 2.90 eV. The low dielectric constant (er) value of FBM crystal is appreciable for microelectronics industry applications. Thermal stability and melting point (130.09 °C) were ascertained by TGA-DSC analysis. The laser-induced surface damage threshold (LDT) value of FBM specimen is found to be 2.14 GW/cm2, it is fairly good compared to other reported NLO crystals. The third - order nonlinear optical character of the FBM crystal was confirmed through the typical single beam Z-scan technique. All these finding authorized that the organic crystal of FBM is favorably suitable for NLO applications.

Potassium pentaborate (KB5) is an excellent nonlinear optical material especially in the UV region. In this work, Li and NH4 doped KB5 crystals were grown using slow evaporation solution growth method. The incorporation of dopant has been confirmed and analysed by Energy dispersive X-ray analysis (EDAX), Inductively coupled plasma (ICP) analysis and Raman spectroscopy. The crystalline perfection of pure and doped KB5 crystals was studied by High resolution X-ray diffraction (HRXRD) analysis. Structural grain boundaries were observed in doped crystals. Second harmonic generation was confirmed for pure and doped crystals and output values revealed the enhancement of SHG efficiency in doped crystals. Resistance against laser damage was carried out using 1064 nm Nd-YAG laser of pulse width 10 ns. The laser damage threshold value is increased in Li doped crystal and decreased in NH4 doped crystal when compared to pure KB5 crystal.

Single crystals of high concentration iron substituted Sm 0.55 Sr 0.45 Mn 0.4 Fe 0.6 O 3 were grown by optical floating zone technique in oxygen atmosphere. Analysis of powder X-ray diffraction and Laue patterns revealed single-phase formation and crystal quality respectively. Replacement of Mn by iron has reduced the ratio of trivalent to tetravalent Mn ions thus suppressing the double exchange interactions and ferromagnetism. The grown crystal exhibits spin glass behavior below 35 K due to the competition between the Mn 3+ -O-Mn 4+ double exchange and the Mn 3+ -O-Fe 3+ super exchange interactions.

The derivative of an organic stilbazolium single crystal, (E)-1-ethyl-2-(4-nitrostyryl) pyridin-1-ium iodide (hereafter abbreviated as NSPI), was synthesized by the Knoevenagel condensation method. Single crystal of NSPI of size 13 × 12 × 3 mm3 were obtained from a 1:1 ratio of methanol and acetonitrile mixed solvent using the slow evaporation technique. X-ray structural analysis has indicated that NSPI crystallizes in the centric triclinic system with the P1 space group. In addition, Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopic analyses were carried out to confirm the molecular structure of the grown crystal. The small energy difference of the frontier molecular orbitals indicates the possible nonlinear optical properties present in the title crystal. Thermal studies confirm that the material has a good thermal stability of about 151 °C. Etching studies provide the layered growth of the NSPI crystal with fewer dislocations. The optical transmission range and the b...

Organometallic crystals offer considerable nonlinear response therefore, present article focuses on bulk growth and investigation of Cu2+ ion doped zinc thiourea chloride (ZTC) crystal to explore its technological impetus for laser assisted nonlinear optical (NLO) device applications. The Cu2+ ion doped ZTC bulk single crystal of dimension 03 × 2.4 × 0.4 cm3 has been grown from pH controlled aqueous solution by employing slow solvent evaporation technique. The structural analysis has been performed by means of single crystal X-ray diffraction technique. The doping of Cu2+ ion in ZTC crystal matrix has been confirmed by means of energy dispersive spectroscopic (EDS) technique. The origin of nonlinear optical properties in Cu2+ ion doped ZTC crystal has been studied by employing the Kurtz-Perry test and Z-scan analysis. The remarkable enhancement in second harmonic generation (SHG) efficiency of Cu2+ ion doped ZTC crystal with reference to ZTC crystal has been determined. The He-Ne laser assisted Z-scan analysis has been performed to determine the third order nonlinear optical (TONLO) nature of grown crystal. The TONLO parameters such as susceptibility, absorption coefficient, refractive index and figure of merit of Cu-ZTC crystal have been evaluated using the Z-scan transmittance data. The laser damage threshold of grown crystal to high intensity of Nd:YAG laser is found to be 706.2 MW/cm2. The hardness number, work hardening index, yield strength and elastic stiffness coefficient of grown crystal has been investigated under microhardness study. The etching study has been carried out to determine the growth likelihood, nature of etch pits and surface quality of grown crystal.

We aimed to investigate the influence potassium tetra thiourea chloride (PTTC) on optical, dielectric and thermal properties of potassium dihydrogen phosphate (KDP) crystals. It was found that by a...

Semi-organic nonlinear optical crystal Calcium5-Sulfosalicylate (CA5SS) was grown by slow evaporation solution growth technique. The cell parameters and molecular structure of the grown crystal were studied by single crystal x-ray diffraction analysis. The presence of various functional groups of the grown crystal was confirmed using Fourier transform infrared (FT-IR), Fourier transform Raman (FT-Raman) analysis. UV–Visible spectrum shows that CA5SS crystals have high transmittance in the range of 330–900 nm. The refractive index, birefringence and transient photoluminescence properties of the grown crystal were analyzed. The frequency doubling of the grown crystal (CA5SS) were studied and compared with that of KDP.

A nonlinear optical material 4-methylpyridinium5-sulfosalicylate has been successfully synthesized, and the optical quality single crystals were grown by slow solvent evaporation solution growth technique at room temperature. The single crystal XRD analysis indicated that the crystal belongs to the monoclinic system with lattice parameters a = 7.07 A, b = 13.45 A, c = 15.57 A. The presence of various functional groups in the crystal was confirmed by FT-IR spectral analysis. The optical transmission window of the 4MSS has been identified by UV–vis–NIR studies. Broadband dielectric analysis has been studied in the frequency range 10 Hz to 20 MHz at room temperature. It is found that the real (e′) and imaginary (e″) dielectric constant, dielectric loss, dielectric modulus depend on frequency. The third order nonlinear optical properties of the grown crystals were investigated using Z-scan technique. The nonlinear index of refraction and nonlinear absorption coefficient were determined to explore the ...

Bulk organic nonlinear optical (NLO) single crystals of DEBM (2-[4-(diethylamino)benzylidene]malononitrile), with sizes up to 22 × 5 × 12 mm3 have been grown in ethyl acetate solution by the slow evaporation method. The lattice parameters and crystalline purity of the titled crystal were measured by single crystal X-ray diffraction and powder XRD, respectively. The morphology of the grown crystal was portrayed by WinXMorph program. Fourier transform infrared (FT-IR) spectral studies have been performed to identify the functional groups. The molecular structure was confirmed through 1H NMR. UV–vis–NIR spectral analysis signifies that the DEBM crystal is transparent in entire visible and near-infrared region, which has a lower cutoff wavelength around 476.8 nm. The optical band gap (Eg) was estimated from the Tauc plot and was found to be about 2.68 eV. The low value of the dielectric constant (er) of DEBM suggests that it has a possible strategy toward the microelectronics industry. Thermal stability and m...

Unidirectional ( plane) 1, 3, 5-triphenylbenzene (3PB) single crystal 150 mm long and 25 mm diameter was grown by SR technique. The grown crystal was subjected to UV–vis-NIR spectral analysis determine linear optical properties over the range of 200–1100 nm. The relevant optical parameters such as transmittance, absorption coefficient, extinction coefficient, band gap energy, reflectance, and refractive index were determined which reveal the suitability of crystal to couple with a photomultiplier tube or other light sensor. The wide band gap energy 3.65 eV of the 3PB crystal shows significant transmittance in the Vis and NIR region. The refractive index of the crystal is determined to be constant above 350 nm, and it confirms the required parameter to set high light yield. The temperature dependence refractive index was measured in the range of 30–70 °C, it illustrates the faster propagation light in the crystal. Third order nonlinear optical parameters of the grown crystal were estimated by Z-scan technique. It showed that the low absorption coefficient and negative refractive index. The second order hyperpolarizability (γ) of 3PB molecule was found to be 8.6411 × 10−34 esu. The obtained all results in the present work which makes the 3PB crystal promising candidate for optical power limits, optical switching and other nonlinear optical applications. The Laser Damage Threshold (LDT) was determined to be 2.1612 GW/cm2 and it confirms the suitability of crystal for device fabrication.

An organic quinolinium derivative crystal 1-ethyl-2-[2-(3,4,5-trimethoxy-phenyl) vinyl]-quinolinium iodide has been synthesized by knoevenagel condensation reaction and the crystals were grown by solution growth method for the first time. The grown crystal structure was confirmed by single crystal X-ray diffraction analysis and it showed that TMQI crystal belong to the triclinic space group P-1. The molecular structure and composition of the crystal was further confirmed by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (FT-NMR) spectroscopic techniques. The thermal stability of the title crystal has been investigated by TG/DSC curves. The linear optical response of the grown crystal has been examined by using UV–Vis-NIR spectral analysis, and the photoluminescence spectrum exhibits strong emission radiation at 558 nm. The chemical etching analysis was carried to reveal the growth pattern of TMQI crystal. Laser induced damage threshold of the title crystal was found to be 1.15 GW/cm2. The third order nonlinear optical property of grown crystal was studied using Z-scan technique and the magnitude of third order nonlinear susceptibility has found to be in the order of 10−3 esu, which is higher than the reported quinolinium derivative crystals.

The present communication is aimed to explore the characteristic properties of salicylic acid (SA) doped potassium dihydrogen orthophosphate (KDOP) crystal. The single SA doped KDOP crystal with optimum dimension of 10 × 08 × 04 mm3 has been grown from solution by slow evaporation at ambient temperature. The single crystal X-ray diffraction analysis has been employed to determine the structure and cell parameters of grown crystal. The Z-scan studies have been carried out at 632.8 nm to ascertain the influential third-order non-linear optical (TONLO) nature of SA doped KDOP crystal. The Z-scan transmittance data have been used to determine the magnitude of TONLO susceptibility (χ3), absorption coefficient (β) and refractive index (n2) of SA doped KDOP crystal. For grown crystal, the surface damage due to exposure of high intensity of Nd:YAG laser operating at 1064 nm has been determined and found of order MW cm−2. The growth tendency, etch pattern and surface quality of grown SA doped KDOP crystal ...

Organic 2-[2-(4-Ethoxy-phenyl)-vinyl]-1-ethyl-stilbazolium iodide (EESI), a derivative of the stilbazolium family single crystal was synthesized by condensation method. Nearly perfect as-gown single crystals of EESI structure was confirmed by single-crystal X-ray diffraction studies. The crystal has a triclinic system with the space group P -1, the molecule consists of one pyridinium cation, one iodide anion, and 0·5H 2 O molecules. The nature of charge transfer, molecular properties, electrostatic potential map, and HOMO-LUMO energy gap of EESI have been theoretically investigated by Sparton’10 V1.0.1 program. The optical transparency of EESI was studied by Uv–Visible spectral analysis. The growth features were observed during the etching studies using a Carl Zeiss optical microscope (50X magnification). The mechanical behavior of the crystal was estimated by Vickers microhardness test, which shows reverse indentation size effect (RISE) with good mechanical stability. Both the dielectric constant and dielectric loss increases with the increasing temperature and attain almost constant at higher frequencies, which justify the crystal quality and essential parameter for electro-optic device applications. The complex impedance analysis explains the electrical property of EESI. TGA and DTA measurements determined the thermal stability of the grown crystal. Laser-induced damage threshold energy measurements exhibit that the excellent resistance with good threshold energy up to 2.08 GW/cm 2 that was found to be more than that of some known organic and inorganic NLO crystals. Photoconductivity of EESI crystal confirms that the positive photoconductivity nature. Also, the third-order nonlinear optical (NLO) properties of EESI were investigated by using the single beam Z-scan technique under the Visible light (632.8 nm) region. The results show that EESI has effective third-order nonlinear optical property with the nonlinear refractive index n 2 =1.787×10 -11 m 2 /W, third-order nonlinear optical susceptibility χ (3) =4.229×10 -6 esu and second-order hyperpolarizability (γ) =1.468×10 –33 esu. It is found to be larger than that of some organic NLO materials. All the obtained results are making it a potential candidate as useful non-linear optical (NLO) applications.

Organic single crystals of new stilbazolium derivative, (E)-4-(3-ethoxy-2-hydroxystyryl)-1-methyl pyridinium iodide (3ETSI), was grown by slow evaporation technique. Single crystal X-ray diffraction study revealed that 3ETSI crystallizes in monoclinic crystal system with centrosymmetric space group P21/c. The characteristic functional groups of the grown crystal were identified by FT-IR spectral studies. The 1H NMR spectral studies further confirm the molecular structure of the grown crystal. The thermal behaviour of 3ETSI crystal was studied by TG/DSC analysis. The grown crystal was found to be transparent in the region between 471 and 800 nm as indicated by the UV–visible spectral studies. Photoluminescence spectrum of 3ETSI crystal shows broad green emission peak at 529 nm. The mechanical strength of the grown crystal was estimated by Vickers microhardness tester. The laser damage threshold of 3ETSI crystal was found to be 2.5 GW/cm2 using Nd: YAG laser (1064 nm). Etching studies enunciate the two-dimensional (2D) layer growth mechanisms in the grown crystal. The third-order nonlinear optical properties including nonlinear refractive index (n2), nonlinear absorption coefficient (β), and third-order nonlinear optical susceptibility (χ(3)) of 3ETSI crystal were investigated by the Z-scan technique using continuous wave (CW) He-Ne laser at 632.8 nm.

An organic nonlinear optical (NLO) material 1,3-bis(4-methoxyphenyl)prop-2-en-1-one (BMP) single crystal has been successfully grown by vertical Bridgman stockbarger technique (VBT) using single wall ampoule. The grown crystal was subjected to single-crystal X-ray diffraction analysis (SXRD) to confirm the cell parameters and powder X-ray diffraction analysis (PXRD) to confirm the crystallinity. FTIR analyses were carried to identify the functional groups. The UV–Vis spectrum of BMP showed the lower optical cut off at 435 nm and is transparent in the visible region. The mechanical property of the titled crystal is analyzed by using microhardness measurements. Laser damage threshold energy was determined using Nd: YAG laser (1064 nm). The photoconductivity study of BMP reveals the positive photoconducting nature. The NLO property of the grown crystal confirmed by Kurtz and Perry powder technique and the SHG efficiency of the grown crystal was obtained to be 1.04 times greater than Urea. Z-scan studies calculated the third order nonlinear optical parameters like refractive index (n2), the absorption coefficient (β) and third order susceptibility (χ3).

A new organic non-linear optical (NLO) single crystal of thiosemicarbazide-4-hydroxybenzenesulfonate Monohydrate (THBSM) was successfully synthesized and single crystals were grown by slow evaporation solution growth technique (SESGT). The single crystal X-ray diffraction studies confirm that the grown crystal crystallizes in monoclinic system with P21/n space group. The asymmetric part of the title crystal contains isolated thiosemicarbazide cation, 4-hydroxybenzesulfonate anion and a water molecule. Thereby, interplay between vast number of intermolecular interactions such as N–H⋯S, N–H⋯O, C–H⋯O, O–H⋯O and O–H⋯S hydrogen bonds are taken for discussion. FT-IR spectral analysis showed the vibrational behaviour of chemical bonds and presence of its functional groups. UV–Vis–NIR spectral analysis reveals that the optical transparency of THBSM is more than 90% in the entire Vis–NIR region, which confirms its colourless nature and suitable candidate for applications in optoelectronic devices. Photoluminescence (PL) spectrum exhibits a sharp and broad emission peak at centered at 415 nm indicates violet emission. Thermal stability and melting point of the titular compound were studied by TG-DSC analysis. The low value of the dielectric constant of THBSM suggests that the crystal can be used in the microelectronics industry. Third-order nonlinear optical parameters of the title crystal were studied by the single beam Z-scan technique at 632.8 nm using a He–Ne laser as a source. Moreover it exhibits strong reverse saturable absorption (RSA) and a self-focusing nature with large second-order hyperpolarizability (γ = 7.304×10−34 esu), which are mainly associated with electronic processes. From the analyzed results, it is clear that the title crystal possesses excellent third-order nonlinear optical (TONLO) properties and it is suitable for all optical switching, optical limiting and photonic applications.

A new organic stilbazolium derivative, 1-Ethyl-2-(2-p-tolyl-vinyl)-pyridinium iodide (TASI), was grown from methanol:acetonitrile (1:3) mixed solvent by slow evaporation technique. Single crystal X-ray diffraction analysis revealed that TASI crystallizes in triclinic system with a centrosymmetric space group P-1. The molecular structure and the presence of expected functional groups of TASI were confirmed by 1H NMR and FT-IR spectroscopic studies. The HOMO and LUMO energies influence the charge transfer takes place within the molecule. The grown crystal was thermally stable up to 210 °C as determined by TG/DTA analysis. UV-Vis-NIR spectral study showed that the grown crystal was transparent in the wavelength range of 438–1100 nm. Mechanical behaviour and surface laser damage threshold were studied to find the suitability of the grown crystal for device fabrication. Studies of its third-order nonlinear optical properties using a Z-scan technique demonstrates that TASI crystal is capable of exhibiting reverse saturable absorption and self-focusing performance with the second-order molecular hyperpolarizability (γ) 4.983 × 10−34 esu. The third-order nonlinear susceptibility of TASI was found to be 8.931 × 10−6 esu, which is higher than a few other stilbazolium derivative crystals.

Ethyl p-aminobenzoate (EPAB) single crystal was grown using vertical Bridgman technique (VBT). The crystal system of grown crystal was identified, and lattice parameters have been measured from the powder X-ray diffraction (PXRD). The optical transparency of EPAB single crystal was 55%, and the cut-off wavelength was found to be 337 nm. The thermal stability of EPAB single crystal was analyzed by thermogravimetric analysis. Etching studie were carried out for the grown crystal using different solvents, and etch pit density (EPD) was calculated and compared. Vickers microhardness (Hv) measurements revealed that EPAB belongs to the category of soft material. The dielectric studies reveal that the dielectric constant and dielectric loss of grown crystal decreases with increasing frequency for various temperatures. The third-order nonlinear optical property of EPAB was investigated and compared with other organic crystals. The evaluation of third-order optical properties such as nonlinear refractive index (n 2 ), nonlinear absorption (β ) and third-order nonlinear susceptibility (χ3) have found to be in the range of 10 − 11 m 2 /W, 10 −4 m/W and 10 −5 esu respectively. The Laser damage threshold energy of EPAB was measured using Nd: YAG laser. The blue emission of the grown crystal was identified by photoluminescence (PL) spectra measurements. The second harmonic generation (SHG) for the grown EPAB crystal was confirmed by Kurtz powder technique.

The present article is focused to investigate the influence of l -cystine (LC) on linear-non-linear optical and laser damage threshold of cadmium thiourea acetate (CTA) crystal. The structural parameters of pure and LC doped CTA crystals have been determined using the single crystal X-ray diffraction technique. The functional groups of grown crystals have been identified by means of fourier transform infrared (FT-IR) analysis. The UV–visible spectral analysis has been done in the range of 200–900 nm to ascertain the uplifting influence of LC on optical properties of CTA crystal. The second harmonic generation (SHG) efficiency of LC doped CTA crystal is found to be higher than CTA and KDP crystal. The Z-scan technique has been employed to determine the third order nonlinear optical (TONLO) nature of LC doped CTA crystal at 632.8 nm. The self focusing tendency confirmed the strong kerr lensing ability of LC doped CTA crystal. The TONLO susceptibility (χ3), refraction (n2) and absorption coefficient (β) has been calculated using the Z-scan data. The laser damage threshold of pure and LC doped CTA crystals has been measured using the Q-switched Nd:YAG laser and its is found to be in range of GW/cm2. The surface analysis has been done by means of etching studies.

A new hybrid organic–inorganic nonlinear (NLO) single crystal, Bis(1H-benzotriazole) hexaaqua-zinc bis(sulfate) tetrahydrate (BZS), has been successfully synthesized and the single crystals were grown by slow evaporation solution growth technique (SESG) using Millipore water as a solvent. The structure of the BZS crystal was solved and refined by single-crystal X-ray diffraction and demonstrates that the grown crystals belong to a triclinic system with the space group P-1. The asymmetric part of the titled compound contains isolated organic cation (C6H6N3)2, metallic cation [Zn(H2O)6]2+, sulfate anion (SO4)2− and free H2O molecules. The interplay between the wide number of intermolecular interaction such as O–H···O, N–H···O, C–H···O and π–π stacking interactions were discussed. The optical transmittance spectrum shows that the crystal is excellent transmittance in the entire Vis–NIR region with the cutoff wavelength at 345 nm. The presences of expected functional groups were identified by Fourier transform infrared spectroscopy. The dielectric measurements were carried out at different temperature in the frequency range 100 Hz–5MHz. Furthermore, the studies of its third-order NLO properties using a Z-scan technique demonstrate that the BZS crystal possesses a strong reverse saturable absorption (RSA) and the self-focusing (SF) nature with large second order hyperpolarizability (γ = 6.24 × 10−34 esu). All the results indicate that BZS crystal might be the potential candidate for the third-order NLO applications.

2-[2-(2,4-Dimethoxy-phenyl)-vinyl]-1-ethyl-pyridinium iodide (DMPI), a new organic stilbazolium derivative was synthesized and grown by slow evaporation technique. The crystal structure of the grown crystal was solved by single crystal X-ray diffraction analysis and it was found that DMPI crystallizes in triclinic structure with the centrosymmetric space group Pī. Various functional groups of the grown crystal were identified using FT-IR spectral analysis. The molecular structure of DMPI was further confirmed by 1H NMR and 13C NMR spectral studies. The linear optical studies revealed that the grown crystal has a wide transparency range from 481 to 800 nm, which is suitable for opto-electronic and nonlinear optical applications. The luminescence spectrum of DMPI showed yellow emission radiation at 571 nm. TG/DTA analysis revealed that the grown crystal was thermally stable up to 232 °C. Microhardness studies confirmed the reverse indentation size effect of DMPI. The dielectric behaviour of DMPI was analyzed by dielectric studies with various frequencies at different temperatures. The surface damage threshold study showed that the grown crystal has higher optical radiation stability against 1064 nm Nd: YAG laser. Studies of its nonlinear optical properties using a Z-scan technique indicated that DMPI crystal possesses a saturable absorption and the self-focusing effect. Negative photo conducting nature of the grown crystal was obtained by photoconductivity measurements.

Glycine doped potassium thiourea chloride (PTC) crystal has been grown by slow solution evaporation technique. The dielectric studies have been employed to examine substantial improvement in dielectric constant and dielectric loss of glycine doped PTC crystal. The etching studies have been performed to investigate the surface quality of this crystal. The z-scan studies have been carried out at 632.8 nm to explore the third order nonlinear optical nature. The negative nonlinear refraction of glycine doped PTC crystal was found to be of 7.27 × 10−12 cm2/W. The origin of high magnitude of third order nonlinear optical susceptibility and reverse saturable nonlinear absorption have been investigated. The obtained results were explored to discuss the nonlinear optical applications of PTC crystal.

The single crystals of l-arginine Acetate (LAA) and Na doped LAA were grown by slow evaporation method and characterized by chemically, structurally, thermally, mechanically and optically. The grown crystals belongs to monoclinic system was confirmed by single crystal X-ray diffraction analysis. The optical absorption spectrum gives the details about cut off wavelength and optical band gap of the grown crystal. The grown crystals were found to be thermally stable up to 202–208 °C. The hardness measurement indicates that the grown crystal of LAA comes under the soft material category and Na doped LAA comes under the hard material category. The nonlinear refractive index n2, non-linear absorption co-efficient (β), and non linear susceptibility χ(3) were calculated by Z-scan technique. The results indicate that the grown crystal of pure and doped LAA exhibits reverse saturation absorption and self defocusing performance.

A new N-ethyl quinolinium derivative of 1-Ethyl-2-(2-p-tolyl-vinyl)-quinoliniumiodide (PTQI) was synthesized by knoevenagel condensation reaction and single crystal was successfully grown by slow evaporation technique. The grown crystal exhibit a centric monoclinic space group P21/C with a third order nonlinear optical response in their crystalline form. The molecular structure of the crystal was studied by single crystal XRD and NMR spectral analysis. FTIR reveal the existence of vinyl group and functional groups of the grown crystal. The melting point and thermal behaviour of PTQI were investigated using TG/DTA analysis. The linear optical study was done by UV–vis–NIR analysis show that the crystal is transparent in the wavelength range of 472–1100 nm. Photoluminescence study shows that PTQI crystal has green luminescence emission property. The etching study reveals that the title crystal encompasses good crystalline nature and lesser amount of dislocations. Third order nonlinear optical property was determined by Z scan technique and the results making grown crystal as a promising material in the field of nonlinear optical devices.

An organic single crystal of 1,3,5-Triphenylbenzene (3PB) has been grown from solution by unidirectional Sankaranarayanan-Ramasamy (SR) method within a period of 72 days. The size of grown crystal was 40 mm length and 30 mm diameter. The solubility of 3PB material was determined in five various solvents with different temperatures and tetrahydrofuran (THF) was used as a suitable solvent for bulk crystallization. Metastable zone width of the solution was determined to optimize the growth period. Cell parameters of the grown 3PB crystal were confirmed by single crystal X-ray diffraction and it belongs to orthorhombic crystal system. The density of the grown 3PB crystal was found to be 1.240 g/cm 3 by floatation method. Optical studies reflect the transmittance ability of crystal in entire visible and NIR region. The refractive index of the grown 3PB crystal was found to be 1.618. Fluorescence emission spectrum was recorded and emission peak observed at 360 nm. Prompt and delayed fluorescence lifetime of 3PB single crystal has been calculated at 12 ns and 30 ns respectively. Thermogravimetric/Differential thermal analysis (TG/DTA) measurement was performed to the grown crystal and it was stable up to 164 °C. Vicker’s microhardness value (H v ) was calculated with varying load ranging from 25 to 100 g and the Mayer’s index was found to be 4.5, showing that the grown crystal belongs to a soft material category. Growth pattern and the surface defect were examined by the optical microscope. The microstructure of the crystal surface shows the regular shapes of etch pits which are in triangular shape.

Vickers and Knoop microhardness studies were done on the (200) face of Ca 0.9 Nd 0.1 Ti 0.9 Al 0.1 O 3 crystals grown by optical floating zone technique for various loads ranging from to 0.24–9.8 N. Various important mechanical properties such as Vickers hardness, Knoop hardness, Young's (elastic) modulus, yield strength, stiffness constant which accounts for various industrial applications were determined. The Indentation Size Effect (ISE) were observed for the grown crystal, four different models such as Meyer's law, Hays-Kendall (HK) model, proportional sample resistance (PSR) model, elastic/plastic deformation model (EPD) were used to determine the true hardness values. Among these four mechanical analysis models, HK approach seemed to be the best model to describe the mechanical properties of the grown crystal. The variation of microhardness number for different orientations showed the presence of microhardness anisotropy in the grown crystal. Laser damage threshold for the grown crystal was found to be 2.49 GWm −2 .

Single crystals of ammonium picrate (AP), having potential applications in optical devices, were grown from a mixed solvent system methanol-acetone (2:1, v/v) by the slow evaporation technique at constant temperature. The structure is elucidated by single crystal X-ray diffraction analysis. The molecule is associated with accommodating weak C H⋯O, N H⋯O, C H⋯N, π…π and H⋯H stacking interactions, very much responsible for the formation and strengthening of supramolecular assembly. Inter- and intramolecular hydrogen bonding interactions show supramolecular architecture in the crystal packing. Two different types of architecture, i.e., a column like packing and cluster network type of infrastructure are observed. Fingerprint analysis was used to locate and analyze the quantity of the molecular interactions. Third-order non-linear optical properties of the grown crystal were derived by employing a single beam Z-scan technique at a wavelength of 532 nm with He-Ne Laser system. Theoretical calculations were performed using density functional theory (DFT) method to derive the optimized geometry, dipole moment, polarizability, HOMO-LUMO energies at different levels, excited state energy and oscillator strength. Estimated large first—order molecular hyperpolarizality of >9.81 times of urea, suggests a charge transfer atmosphere facilitating micro level nonlinearity. Idea about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density with electrostatic potential.

Single crystals of Samarium orthoferrite (SmFeO 3 ) have been grown by the optical floating zone technique. The growth parameters to yield good quality crystals are 5 mm/h for pulling and 30–40 rpm for rotation. The mechanical behavior of the grown crystal has been investigated. Rosette pattern has been observed around the indentation and the microhardness has been found to decreases non-linearly with the applied load. For load higher than 1.96 N there is a transition from palmqvist to median crack due to plastic deformation of the crystal. The hardness parameters like fracture toughness, brittleness index, and yield strength have also been calculated for palmqvist and median cracks occurring on the crystal surface. The magnetic investigations revealed that a magnetic transition in the range of 300–180 K. Above 180 K, the magnetization decreases as Sm and Fe sublattices have opposite spins. At high temperature, two anomalies are observed, one due to near spin reorientation (T SR = 480 K) and the other is AFM to paramagnetic transitions (T N = 670 K). The M–H curves exhibit a shape change with temperature due to the emergence and enlargement of multi-domain state of the SmFeO 3 crystals. Bloch parameter (3.28 × 10 −5 K −3/2 ) has also been evaluated.

Single crystals of 9,10-diphenylanthracene (DPA) were grown by slow evaporation solution growth technique. The grown crystal was confirmed by single crystal. Powder X-ray diffraction was carried ou...

Single crystals of 2-[2-(4-cholro-phenyl)-vinyl]-1-methylquinolinium naphthalene-2-sulfonate (4CLNS) were grown by a slow evaporation technique. The formation of molecule was confirmed from 1 H NMR and FTIR analysis. The confirmation of crystal structure was done by single crystal XRD and atomic packing of grown crystal was identified. The grown single crystal crystallized in triclinic structure with centrosymmetric space group P-1. The crystalline nature of the synthesised material was recorded by powder XRD. The optical absorption properties of the grown crystals were analyzed by UV–vis spectral studies. The thermal behaviour of the title material has been studied by TG/DTA analysis which revealed the stability of the compound till its melting point 276.7 °C. The third order nonlinear optical property of 4CLNS was investigated in detail by Z scan technique and it confirms that the title crystal is suitable for photonic devices and NLO optical applications. Emissions at 519 nm in green region of the EM spectrum were found by photoluminescence studies. The charge transfer occurring within the molecule is explained by the calculated HOMO and LUMO energies.

More effective organic charge transfer nonlinear optical material of 2-(4-methlybenzylidene) malononitrile (MBM) has been synthesized via knoevenagel condensation reaction method and single crystals of unprecedented MBM were successfully cultivated in the presence of ethanol solution by the adaption of slow evaporation solution growth method. Cell parameters and phase purity of the obtained MBM crystals were investigated with the help of Single crystal and powder X-ray diffraction analysis. The morphology of the grown crystal was generated using WinXMorph software. Linear optical characterization was carried out in order to figure out its transmittance efficiency (82%), cut-off wavelength (λ = 458 nm) and energy band gap (Eg = 3.05eV) of the title material. Electrical behavior of the MBM crystal was examined on the basis of dielectric properties. Title crystals thermal tolerance and melting point was examined through TG-DSC analysis. The grown MBM crystal was subjected to Single beam Z-scan technique in order to figure out its third order nonlinear optical nature and its susceptibility is compared with other reported centrosymmetric crystals. Considering its large transmittance range, thermal stability and effective NLO performance, MBM is a potential candidate for NLO applications.

Studies on organic scintillation single crystal 1,1,4,4-Tetraphenyl-1,3-Butadiene (TPB) grown by vertical Bridgman technique for the first time is reported. Structural analysis was carried out with Single crystal and Powder X-ray diffractometer which is confirmed the cell parameters of the grown crystal. A definite vibrational analysis was identified on the fundamental modes of vibration. The refractive index of 1.618 was recorded by Abbe refractometer. UV–Vis near IR spectrum was used to determine the absorption edge and found to be 419 nm. The bandgap energy of the crystal was found to be 2.89 eV. Fluorescence spectra of the crystal exhibit a broad emission band at 440 nm. The fluorescence lifetime of TPB measured by TCSPC method reveals a short decay time of 16 ns for prompt and 40 ns for delayed. Photoconductivity of TPB exhibits the positive photoconductivity nature. The Vickers microhardness were used to determine the hardness number (Hυ) and Meyers index of the grown crystal. Essential Mechanical properties such as stiffness constant and yield strength were calculated. Chemical etching was carried out to study the defects and growth mechanism involved in the grown crystal and the etching characteristics of the crystal surface enunciate the 2-dimensional layer growth.

A novel organic nonlinear optical crystal, bis (4-acetylanilinium) tartrate (B4AAT) has been synthesized and successfully grown by a slow evaporation method using acetone as a solvent at ambient temperature. The single-crystal X-ray diffraction study reveals that B4AAT crystallized into a triclinic system with the noncentrosymmetric space group (P1). The crystalline perfection of the grown crystal was affirmed by the High-resolution XRD study. The characteristic functional groups with vibrational assignments and molecular structure of B4AAT were confirmed through Infrared, Raman and NMR spectroscopic analyses. UV–Vis–NIR spectral analysis of the crystal shows 69% of transmittance with a lower cut-off wavelength at 334 nm. The grown crystal was thermally stable up to 143.39 °C. The laser-induced damage threshold of the B4AAT compound was found to be 15.78 GW/cm2 for 1064 nm Nd: YAG laser radiation. The grown B4AAT possesses the low value of dielectric constant and piezoelectric charge coefficient (d33 = 5.86 pC/N) for the supercapacitor and microelectronics industry. The size-dependent of second harmonic generation efficiency of the crystal was found to be 4.6 times higher than that of KDP. The photoluminescence and lifetime measurements of the molecules in the crystal were studied by Fluorescence spectral analysis. The third-order nonlinear optical activity estimated utilizing the Z-scan method reveals that the B4AAT possesses saturable absorption, negative nonlinearity with self-defocusing and optical limiting effect. The aforesaid results confirm that B4AAT crystal is a potential candidate for optoelectronic and nonlinear optical device applications.

Single crystal of organic nonlinear optical material 3-(4-Fluorophenyl)-1-(4-methoxyphenyl) (FMP) was grown with the help of single walled glass ampoule in vertical Bridgman technique. The structural analysis confirmed the cell parameters and crystallinity of the single crystal with the space group of Pbca. The presences of desired components in the single crystal were confirmed by the NMR spectrum. The lower cut off wavelength of the single crystal was observed at 423 nm from the absorption spectra of the single crystal. The electrical property of grown single crystal was studied by measuring the dielectric constant and dielectric loss. The surface hardness test and amount of damage caused by incident laser beam on the surface of the single crystal determined the mechanical strength of the crystal. The FMP single crystal was found to exhibit negative photoconductive nature. The etch pit density and non-linear optical properties were determined by etching measurement and by observation of green light in Kurtz-Perry powder method. The grown crystal was studied thermal stability and melting point with TGA-DSC analysis.

The organic third-order non-linear optical crystal 1-ethyl-2-[2-(4-hydroxy-phenyl)-vinyl]-pyridinium iodide (HSPI), a new derivative of the stilbazolium family, was successfully synthesized and the optical quality single crystal was grown by a slow evaporation technique for the first time. The crystal structure of HSPI was confirmed by single crystal X-ray diffraction studies and it was found that it belongs to the monoclinic system with centrosymmetric space group C2/c. The molecular structure of the grown crystal was further confirmed by 1H NMR and FTIR analysis. Theoretical calculations were performed to derive HOMO–LUMO energies and dipole moment by using the Spartan'14 V1.0.1 program. The UV-Vis-NIR spectral studies exhibit a huge transparency (∼70%) in the visible and near-IR (from 468 to 1100 nm) spectral regions that make it a potential material for non-linear device applications in this spectral range. The luminescence spectrum of the grown crystal showed green emission at 528 nm. The thermal stability of HSPI was found to be 226.6 °C. Mechanical behaviour was estimated by Vickers microhardness test. Dielectric studies were carried out as a function of frequency, and the results are discussed. The growth mechanism of HSPI was assessed by chemical etching studies. The title crystal shows excellent resistance to laser radiation with a high threshold up to 6.93 GW cm−2 and it is compared with other NLO materials. The third-order nonlinear optical susceptibility of HSPI was derived using the Z-scan technique, and it was 4.40 × 10−4 esu. The negative nonlinear refractive index, n2 = −7.29 × 10−12 m2 W−1, is an indication of self-defocusing optical nonlinearity of the sample. It is believed that HSPI is a promising new candidate for developing efficient photonic and optical power limiting devices.

N-Ethyl quinolinium chromophore crystal 2-[2-(4-chloro-phenyl)-vinyl]-1-ethyl-quinolinium iodide (PCLQI) has been successfully grown by the slow evaporation technique. Single crystal X-ray diffraction studies revealed that the title compound crystallizes in the monoclinic crystal system with the centrosymmetric space group C2/c. The molecular formation of the grown crystal was initially identified using 1H NMR and FTIR analysis. The linear optical studies of the title crystal were done by UV-vis-NIR studies and the thermal studies revealed the stability of the title material till its melting point at 239.7 °C. The grown crystal exhibited high third order optical nonlinearity which was determined by the Z-scan technique.

A novel organic nonlinear optical crystal, 2,6 diaminopyridinium tosylate (2,6DPT), was synthesized and grown by the slow evaporation method. Formation of the new crystalline compound was confirmed by single-crystal X-ray diffraction study. The title compound (2,6DPT) crystallizes in the monoclinic crystal system with space group of P21/c. The crystalline perfection of the as-grown crystal was assessed by high-resolution X-ray diffraction study and the quality of it is reasonably good. The thermal stability of 2,6DPT is found to be 180 °C by thermogravimetric and differential thermal (TG–DTA) analyses. The specific heat capacity of 2,6DPT is found to be 3.86 J g−1 K−1. UV–Vis–NIR spectral study showed that the grown crystal is transparent in the entire visible region with the lower cut-off wavelength of 380 nm. The laser-induced surface damage threshold of grown crystal was measured to be 0.2538 GW cm−2 for 1064 nm Nd:YAG laser radiation. Nonlinear refractive index (n 2), absorption coefficient (β) and third-order nonlinear susceptibility (χ(3)) were measured by Z-scan technique.