M. Lydia Caroline

Growth, structural, vibrational, optical, laser and dielectric aspects of l-alanine alaninium nitrate single crystal

Bulk single crystals of l-alanine alaninium nitrate [abbreviated as LAAN], an intriguing material for frequency conversion has been grown from its aqueous solution by both slow solvent evaporation and by slow cooling techniques. The optimized pH value to grow good quality LAAN single crystal was found to be 2.5. The grown crystals were subjected to single crystal X-ray diffraction studies to determine the unit cell dimensions and morphology. Vibrational frequencies of the grown crystals by Fourier transform infrared spectroscopic technique were investigated. Also, the presence of hydrogen and carbon atoms in the grown sample was confirmed using proton and carbon NMR analyses. The dielectric constant and dielectric loss measurements of the as grown crystal at different temperatures and frequencies of the applied field are measured and reported. LAAN has good optical transmission in the entire visible region with cutoff wavelength within the UV region confirms its suitability for device fabrications. The existence of second harmonic generation signals was observed using Nd:YAG laser with fundamental wavelength of 1064 nm. Its Laser Damage Threshold (LDT) was measured and also tested by using a Q-switched Nd:YAG laser and the value of LDT of LAAN is 17.76GW/cm2 respectively, is found to be better than certain organic and semiorganic materials.

Growth, structural, spectral, optical, and thermal studies on amino acid based new NLO single crystal: l-phenylalanine-4-nitrophenol

A new organic nonlinear optical single crystal, L-phenylalanine-4-nitrophenol (LPAPN) belonging to the amino acid group has been successfully grown by slow evaporation technique. The lattice parameters of the grown crystal have been determined by X-ray diffraction studies. FT-IR spectrum was recorded to identify the presence of functional group and molecular structure was confirmed by NMR spectrum. Thermal strength of the grown crystal has been studied using TG-DTA analyses. The grown crystals were found to be transparent in the entire visible region. The existence of second harmonic generation signals was observed using Nd:YAG laser with fundamental wavelength of 1064 nm.

Growth and Characterization of Nonlinear Optics (NLO) Active L-Phenylalanine Fumaric Acid (LPFA) Single Crystal

Organic nonlinear optical crystals of L-phenylalanine fumaric acid [C9H11NO2. C4H4O4] (LPFA), belonging to the amino acid group, has been successfully grown by slow evaporation technique using water as solvent. Transparent crystals up to 7.0 × 7.5 × 1.0 mm3 were obtained. The lattice parameters of the grown crystal have been determined by X-ray diffraction studies. Vibrational spectra were recorded to determine the symmetries of molecular vibrations. LPFA crystal was analyzed by differential thermal and thermogravimetric analyses (DTA-TG) to obtain its thermal stability. Optical absorption study confirms the suitability of the crystal for device applications. The existence of second harmonic generation signals was observed using Nd:YAG laser with fundamental wavelength of 1,064 nm.

Crystal growth, structural, optical, spectral and thermal studies of tris(L-phenylalanine)L-phenylalaninium nitrate: a new organic nonlinear optical material.

Tris(L-phenylalanine)L-phenylalaninium nitrate, C(9)H(12)NO(2)(+)·NO(3)(-)·3C(9)H(11)NO(2) (TPLPN), a new organic nonlinear optical material was grown from aqueous solution by slow evaporation solution growth at room temperature. The grown crystals were subjected to powder X-ray diffraction and single crystal X-ray diffraction studies to confirm the crystalline nature and crystal structure. The modes of vibration of different molecular groups present in TPLPN have been identified by FTIR spectral analysis. The presence of hydrogen and carbon in the grown crystal were confirmed by using proton and carbon nuclear magnetic resonance (NMR) spectral analyses. The optical transmission spectral study establishes good transmitting ability of the crystal in the entire visible region. The thermogravimetric (TG) and differential thermal analyses (DTA) were carried out to understand the thermal stability of the sample. The nonlinear optical property of the compound observed using Kurtz powder second harmonic generation test assets the suitability of the grown material for the frequency conversion of laser radiation of Nd:YAG.

Crystal growth, structural, optical, dielectric and thermal studies of an amino acid based organic NLO material: l-Phenylalanine l-phenylalaninium malonate

Good transparent single crystals of L-phenylalanine L-phenylalaninium malonate (LPPMA) have been grown successfully by slow evaporation technique from aqueous solution. Single crystal X-ray diffractometer was utilized to measure unit cell parameter and to confirm the crystal structure. The chemical structure of compound was established by FT-NMR technique. The vibrational modes of the molecules of elucidated from FTIR spectra. Its optical behaviour has been examined by UV-vis spectral analysis, which shows the absence of absorbance in the visible region. Thermal properties of the LPPMA crystal were carried out by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) techniques, which indicate that the material does not decompose before melting. The melting point of grown crystal was observed as 180°C by melting point apparatus. The NLO property was confirmed by the powder technique of Kurtz and Perry. The dielectric behaviour of the sample was also studied for the first time.

Synthesis, structural, optical, thermal and dielectric studies on new organic nonlinear optical crystal by solution growth technique.

Single crystals of L-phenylalanine-benzoic acid (LPBA) were successfully grown from aqueous solution by solvent evaporation technique. Purity of the crystals was increased by the method of recrystallization. The XRD analysis confirms that the crystal belongs to the monoclinic system with noncentrosymmetric space group P21. The chemical structure of compound was established by FT-NMR technique. The presence of functional groups was estimated qualitatively by Fourier transform infrared analysis (FT-IR). Ultraviolet-visible spectral analyses showed that the crystal has low UV cut-off at 254 nm combined with very good transparency of 90% in a wide range. The optical band gap was estimated to be 6.91 eV. Thermal behavior has been studied with TGA/DTA analyses. The existence of second harmonic generation (SHG) efficiency was found to be 0.56 times the value of KDP. The dielectric behavior of the sample was also studied for the first time.

Growth and Characterization of Chloro Bis Thiourea Mercury (II) Chloride (CBTMC) Grown by Slow Evaporation Technique for Nonlinear Optical Applications

A noncentrosymmetric hard anisotropy crystals of Chloro bis thiourea mercury (II) chloride (CBTMC),[HgCl [CS(NH2)2]2Cl], was synthesized using water as solvent and grown by slow solvent evaporation method and its properties are reported for the first time to attest its suitability in nonlinear optical applications. CBTMC single crystals possessing good morphology with size up to 0.6 × 0.4 × 0.2 cm3 were collected from the crystallization vessels after 12 days. Crystallography structure diffraction analysis using X-radiation confirms the non-centrosymmetric (polar) space group Pmmn, which is the key requirement to exhibit nonlinear optical activity. The crystals are analyzed by powder X-ray diffraction (PXRD) to assess the good crystalline nature. The existence of various functional groups in the synthesized compound were manifested and examined by FTIR spectrum. The thermal analysis disclosed the maximum temperature of operation of 253 °C for CBTMC. The EDAX spectrum emphasized the presence of mercuric chloride in the metal complex. CBTMC crystal was subjected to SEM analysis and it divulged the surface topographies. The UV-Visible spectra revealed the absorption edge down to near UV absorption wavelength at 213 nm, which is a deciding property for SHG. From the UV absorption data optical direct band gap is assessed (Eg = 4.62 eV). The powder visible SHG response was judged by Kurtz-Perry method using a fundamental pulsed Nd: YAG laser radiation (λ = 1064 nm) and SHG efficiency was determined to be 0.736 times that of KDP, moreover KDP is phase-matchable.

Growth, optical, photoluminescence, dielectric, second and third order nonlinear optical studies of benzoyl valine acentric crystal

ABSTRACT A nonlinear optical material benzoyl valine (BV) was synthesized by the technique of slow evaporation process at room temperature. The single crystal X ray diffraction analysis evince that crystal corresponds to acentric space group P21 with monoclinic system. The diverse optical properties assured an elevated transparency in BV crystal. Photoluminescence profile revealed the suitability of crystal for fabricating violet lasers. The Laser damage threshold and the dielectric behavior of the grown crystal were analyzed to indicate its practical applications. The second and third order nonlinear optical measurements were studied to prove its potentiality in the domain of nonlinear optical applications.