Value Of Third Order Nonlinear Susceptibility Research Articles

Remarkable Nonlinear Properties of a Novel Quinolidone Derivative: Joint Synthesis and Molecular Modeling.

A novel 4(1H) quinolinone derivative (QBCP) was synthesized and characterized with single crystal X-ray diffraction. Hirshfeld surfaces (HS) analyses were employed as a complementary tool to evaluate the crystal intermolecular interactions. The molecular global reactivity parameters of QBCP were studied using HOMO and LUMO energies. In addition, the molecular electrostatic potential (MEP) and the UV-Vis absorption and emission spectra were obtained and analyzed. The supermolecule (SM) approach was employed to build a bulk with 474,552 atoms to simulate the crystalline environment polarization effect on the asymmetric unit of the compound. The nonlinear optical properties were investigated using the density functional method (DFT/CAM-B3LYP) with the Pople’s 6-311++G(d,p) basis set. The quantum DFT results of the linear polarizability, the average second-order hyperpolarizability and the third-order nonlinear susceptibility values were computed and analyzed. The results showed that the organic compound (QBCP) has great potential for application as a third-order nonlinear optical material.

Large optical nonlinearity of Au nanoparticle-dispersed Ba0.6Sr0.4TiO3 films prepared by pulsed laser deposition

Crystallized Au nanoparticle-dispersed Ba0.6Sr0.4TiO3 (Au : BST) thin films were prepared on MgO (1 0 0) substrates by pulsed laser deposition. The peak of the linear absorption coefficient for the film shifts to longer wavelength with an increase in Au concentration. Among all the tested samples, the largest values of third-order nonlinear susceptibility were calculated to be −1.93 × 10−6 esu and 1.13 × 10−5 esu corresponding to imaginary and real parts, respectively, which were determined by a single beam Z-scan at a wavelength of 532 nm with a laser duration of 10 ns. The relationship between Au concentration and third-order nonlinear susceptibility was also analysed.

Continuous control of third-order optical nonlinearity in charge-transfer-type conjugated polymers

Third-order optical nonlinearity was investigated in two charge-transfer (CT)-type conjugated polymers, poly(aryleneethynylene) and poly(thiophene-alt-thiazole), using the third-harmonic generation (THG) method. Comparison of the results with previously obtained THG data for polythiophene and the strong CT polymer poly(thiophene-alt-quinoxaline) revealed that the ratio of the maximum value of third-order nonlinear susceptibility and the absorption coefficient max∣χ(3)∣∕αmax increased as the degree of CT character increased for the four polymers. This variation in max∣χ(3)∣∕αmax is discussed based on the magnitude of the transition dipole moment between the one-photon-allowed and the one-photon-forbidden excited states.

Large optical third-order nonlinearity of composite thin film of carbon nanotubes and BaTiO 3

Composite thin films of multiwalled carbon nanotubes and BaTiO 3 prepared by pulsed-laser deposition technique are investigated, which have large optical third-order nonlinearity. We characterized the films by using scanning electron microscopy, Raman spectroscopy, UV–vis absorption and X-ray diffraction. The observation reveals that the multiwalled carbon nanotubes are coated by the amorphous BaTiO 3. Nonlinear optical properties of the composite films are investigated by z-scan technique. The result shows that the value of third-order nonlinear susceptibility χ (3) has achieved as high as 10 −6 esu, which is more than three orders of magnitude larger than that of carbon nanotubes in suspension.

Thin films of Sb2S3 doped by Sm3+ ions

Pure and Sm3+ doped amorphous thin films of Sb2S3 were prepared by thermal co-evaporation of Sb2S3 and Sm metal. The prepared films contained a slight over-stoichiometric excess of Sb. From transmittance measurement, the absorption edge, index of refraction, n, thickness, d, optical gap, Egopt, relative permittivity, εr, single oscillator energy, Eo, dispersion energy, Ed, and the values of third-order nonlinear susceptibility χ(3) were evaluated. The values of χ(3) increase with Sm doping. Some of above-mentioned values are slightly influenced by exposure of films to a UV lamp. The Raman spectra revealed two main structural units in the films: SbS3 pyramids and Sb–Sb bonds in S2Sb–SbS2 structural units. Three luminescence bands were found. The first one with maximum near 1130 nm can be assigned to 6F9/2→6H5/2 and/or 6F11/2→6H7/2 electron transitions, which are overlapping. The second band can be assigned to the electron transition 6F11/2→6H9/2 or 6F9/2→6H7/2 or 6F7/2→6H5/2. The third luminescence band with maximum near 1500 nm can be probably assigned to the electron transition 6F11/2→6H11/2.

Third-order optical non-linearities of CuCl-doped glasses in a near resonance region

Third-order optical non-linearities of CuCl microcrystallites with sizes of 6.8-11.0 nm in glasses were investigated. Absolute values of third-order non-linear susceptibilities, |χ (3) (-ω 1 : ω 1 , -ω 1 , ω 1 )|, were measured in the resonance region by a degenerate four-wave mixing method and |χ (3) (-ω 2 : ω 1 , -ω 1 , ω 2 )| were measured in the near resonance region by a non-degenerate four-wave mixing method. |χ (3) (-ω 1 : ω 1 , - ω 1 , ω 1 )| was strongly dependent on the frequency, ω 1 , of incident beam, while |χ (3) (-ω 2 : ω 1 , - ω 1 , ω 2 )| was less dependent on the frequency, ω 2 , of incident beam under the resonant excitation condition. In the non-degenerate four-wave mixing configuration in which the pumping frequency is resonant with the confined excitons, the figure of merit, |χ (3) |/α, was enhanced to more than an order of magnitude compared with that in the degenerate four-wave mixing configuration in a near resonance region.