AbstractA new organic nonlinear optical single crystal, 1,4-diamino-2,5-dichlorobenzenium picrate (DADCBP) has been successfully grown by solvent slow evaporation method. DADCBP crystallizes in a triclinic structure with the centrosymmetric space setup, P-1. The molecular structure of the grown crystal has been determined by NMR spectral analysis. The existence of discrete functional branches of the crystal has been identified by FTIR spectral study. The optical property of the title crystal has been measured by UV-Vis-NIR spectral analysis. PL spectra reveal the emission bands of the grown crystal. The thermal stability of the harvested crystal has been examined by the TG/DTA study. The dielectric constant and loss have been taken to locate the arrangement of charges in the grown crystal. The quantum chemical studies have been performed to analyze the HOMO/LUMO, molecular geometry, and mulliken atomic charge by B3LYP at the 6-311++G (d,p) level of theory. H···H, O···H, C···H, C···C various intermolecular interactions of hydrogen bonds in the DADCBP molecule have been visualized by the Hirshfeld surface analysis. The nonlinear optical (NLO) characteristics like nonlinear absorption coefficient (β), nonlinear refractive index (n2) and susceptibility (χ(3)) have been examined using the Z-scan technique.Keywords: Crystal structureNMRdensity functional theorydielectricsHirshfeld surface analysisnonlinear optics Disclosure statementNo potential conflict of interest was reported by the author(s).
Organic nonlinear optical single crystal of 2-aminopyridinium maleate (2APM) was grown using a slow evaporation method. The single crystal X-ray diffraction study reveals that the crystals possess to monoclinic system with acentric space group Pc. The Fourier Transform Infrared spectrum is used to identify the sample functional group. Lower cutoff wavelengths have been seen down to 342 nm and the direct optical band gap has been calculated to be 5.9 eV in this region of the spectrum. The microhardness of the 2APM sample was refined using a Vicker's microhardness tester under matching stress. DSC analysis was used to assess the crystal thermal stability. The 2APM crystal dielectric behavior was investigated over a range of frequencies. The Nd: YAG laser was utilized to create the second harmonic waveform. The 2APSS crystal emission spectrum was uncovered during a photoluminescence experiment. Third-order nonlinear susceptibility χ(3) = 5.741 x 10−8 of 2APM formed crystal was utilized to estimate the values for third-order NLO exploits.
Rare earth doped barium tellurite glasses were synthesised and explored for their radiation shielding applications. All the samples showed good thermal stability with values varying between 101 °C and 135 °C based on dopants. Structural properties showed the dominance of matrix elements compared to rare earth dopants in forming the bridging and non-bridging atoms in the network. Bandgap values varied between 3.30 and 4.05 eV which was found to be monotonic with respective rare earth dopants indicating their modification effect in the network. Various radiation shielding parameters like linear attenuation coefficient, mean free path and half value layer were calculated and each showed the effect of doping. For all samples, LAC values decreased with increase in energy and is attributed to photoelectric mechanism. Thulium doped glasses showed the highest value of 1.18 cm−1 at 0.245 MeV for 2 mol.% doping, which decreased in the order of erbium, holmium and the base barium tellurite glass, while half value layer and mean free paths showed an opposite trend with least value for 2 mol.% thulium indicating that thulium doped samples are better attenuators compared to undoped and other rare earth doped samples. Studies indicate an increased level of thulium doping in barium tellurite glasses can lead to efficient shielding materials for high energy radiation.
Solid-state dye-doped polymers are an attractive alternative to the conventional liquid-dye solutions. The search for new materials which have potential application in optoelectronic devices has lead us to probe the organic dyes. The solid state being a better medium when compared to a liquid medium has lead to the incorporation of dyes in the polymer matrix. The study of nonlinear characteristics of dyes in polymeric media is essential for developing such potential application devices. In this paper, the third-order nonlinear optical properties of three dyes from the Triarylmethane family were measured in 1-Butanol and in dye-doped polymer films by the Z-scan technique using a cw diode-pumped Nd:YAG laser at 532 nm. The Z-scan technique has also been used to present the observation of a nonlinear refractive index resulting from the photochromism of one of the dyes. These materials exhibit a large negative optical nonlinearity resulting due to the thermal effect. The relative contributions from the nonlinear absorption (NLA) and nonlinear refraction (NLR) are dependent on the chemical structure and linear absorption of the dyes. The dyes exhibited a nonlinear refractive coefficient n 2, a nonlinear absorption coefficient β, and susceptibility x(3) on the order of 10−8 cm2/W, 10−4 cm/W, and 10−6 esu, respectively, in both liquid and solid media. The results show that these dyes have potential applications in nonlinear optics.
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