Structure and Nonlinear Refractive Index of Bismuth Borate Glass

The method of conventional glass melting is used to study the glass formation region of Bi2O3-B2O3-TiO2-La2O3 system. The instrument of Differential Scanning Calorimeter （DSC） is used to research the glass stability. Raman spectra and IR spectra are used to speculate on the structure of glasses. The refractive index of glass is measured by prism coupler. With increase of Bi2O3, the glass stability, the amount of [BiO3] group and boron-oxygen loops decrease, while the content of B-O- bond, refractive index and nonlinear refractive index increase.

Nonlinear Refractive Index and Absorption Coefficient of Single-Shell Semiconductor Carbon Nanotube

The nonlinear refractive index and absorption coefficient of single\|shell semiconductor carbon nanotubes(CN s ) are calculated based on the two\|band approximation and Genkin\|Mednis approach. The results of nonlinear refractive index and absorption coefficient reach the order of 10 -8 and 10 -4 cm 2\5W -1 separately, which indicates that CN s have wonderful nonlinear optical properties. Taking into account the temperature effect and overlapping of σ and π orbits, the effect of relaxation term and chiral angle is discussed. The results show that the smaller the relaxation term, the larger the nonlinear absorption coefficient and refractive index. At the same time, CN s with different chiral angles have different results due to their different energy gap.

Effect of Si δ-Doping on the Linear and Nonlinear Optical Absorptions and Refractive Index Changes in InAlN/GaN Single Quantum Wells

In the framework of effective mass approximation, we theoretically investigate the electronic structure of the Si δ-doped InAIN/GaN single quantum well by solving numerically the coupled equations Schrodinger-Poisson self-consistently. The linear, nonlinear optical absorption coefficients and relative refractive index changes are calculated as functions of the doping concentration and its thickness. The obtained results show that the position and the amplitude of the linear and total optical absorption coefficients and the refractive index changes can be modified by varying the doping concentration and its thickness. In addition, it is found that the maximum of the optical absorption can be red-shifted or blue-shifted by varying the doping concentration. The obtained results are important for the design of various electronic components such as high-power FETs and infrared photonic devices.

Orientation-enhanced nonlinear optical properties and phase-conjugate reflective system of a novel Azobenzene doped polymer film

This paper reports that the nonlinear refractive index of a novel organic optical storage film doped azodiphenylamine polymer is measured by using the Z-scan technique. The nonlinear refractive index up to 3.7× 10^-6 cm^2/W induced by thermo-optical effect is obtained. It indicates that the sample has excellent optical non- linear properties. The physical mechanism of the great nonlinear optical effect is analysed and the optical conjugate characteristic is also discussed with degenerate four-wave-mixing. The phase conjugate wave diffracted from the formative refractive index grating in the sample is acquired and its equivalent reflectivity reaches about 22%. On this basis, the reflective wave phase-conjugated mirror system was designed, and the image aberration experienced in propagation in the storage experiment is corrected by using the system.

Physical origin of observed nonlinearities in Poly(1-naphthyl methacrylate):Using a single transistor–transistor logic modulated laser beam

A thermal lens technique is adopted using a single modulated continuous wave （cw） 532-nm laser beam to evaluate the nonlinear refractive index n2, and the thermo-optic coefficient dn/dT, in polymer Poly （1-naphthyl methacrylate） （P-1-NM） dissolved in chloroform, tetrahydrofuran （THF）, and dimethyl sulfoxide （DMSO） solvents. The results are compared with Z-scan and diffraction ring techniques. The comparison reveals the effectiveness and the simplicity of the TTL modulation technique. The physical origin is discussed for the obtained results.

Nonlinear optical characterization of phosphate glasses based on ZnO using the Z-scan technique

The nonlinear optical properties of a phosphate vitreous system [（ZnO）x-（MgO）30-x-（P2O5）70], where x=8, 10, 15, 18, and 20 mol% synthesized through the melt-quenching technique have been investigated by using the Z-scan technique. In the experiment, a continuous-wave laser with a wavelength of 405 nm was utilized to determine the sign and value of the nonlinear refractive （NLR） index and the absorption coefficient with closed and opened apertures of the Z-scan setup. The NLR index was found to increase with the ZnO concentration in the glass samples by an order of 10-10 cm2·W-1. The real and imaginary parts of the third-order nonlinear susceptibility were calculated by referring to the NLR index （n2） and absorption coefficient （β） of the samples. The value of the third-order nonlinear susceptibility was presented by nonlinear refractive or absorptive behavior of phosphate glasses for proper utilization in nonlinear optical devices. Based on the measurement, the positive sign of the NLR index shows a self-focusing phenomenon. The figures of merit for each sample were calculated to judge the potential of phosphate glasses for application in optical switching.

Tunable nonlinear refractive index of two-dimensional MoS2, WS2, and MoSe2 nanosheet dispersions [Invited]

Liquid-phase-exfoliation technology was utilized to prepare layered MoS2, WS2, and MoSe2 nanosheets in cyclohexylpyrrolidone. The nonlinear optical response of these nanosheets in dispersions was investigated by observing spatial self-phase modulation（SSPM） using a 488 nm continuous wave laser beam. The diffraction ring patterns of SSPM were found to be distorted along the vertical direction right after the laser traversing the nanosheet dispersions. The nonlinear refractive index of the three transition metal dichalcogenides dispersions n2 was measured to be 10-7cm2W-1, and the third-order nonlinear susceptibility χ（3）10-9 esu. The relative change of effective nonlinear refractive index Δn2e∕n（2e） of the MoS2, WS2, and MoSe2 dispersions can be modulated 0.012–0.240, 0.029–0.154, and 0.091–0.304, respectively, by changing the incident intensities. Our experimental results imply novel potential application of two-dimensional transition metal dichalcogenides in nonlinear phase modulation devices.

Z-SCAN TECHNIQUE FOR MEASUREMENT OF TOTAL CHOLESTEROL AND TRIGLYCERIDES IN BLOOD

The measurement of cholesterol and triglycerides in blood by Z-scan technique is proposed.The nonlinear refractive index of cholesterol and triglycerides was found to vary linearly with concentration.Hence by calculating the nonlinear refractive index it is possible to measure their concentration in the sample.These measured values are found in equivalence with conventional colorimetric method.

Nonlinear Refractive Index Measurement Utilizing Bistable Behavior of Double Coupling Optical Fiber Ring Resonator

A novel approach for measuring the nonlinear refractive index of an optical fiber utlizing the bistable behavior of the double coupling optical fiber ring resonator was proposed and investigated. The switch-off or switch-on power decreases with an increase in the nonlinear refractive index n2 （m2/W）, and the dependence of swith-off or switch-on power on the nonlinear refractive index was analyzed numerically. Simulation results showed that the switch-off power and switch-on power （in dBW） decreased linearly with loglo （n2） in a 100-m-length fiber ring resonator, when n2 changed from 3.2 ×10^-20 m2/W to 2.5 × 10^-17 m2/W or nearly n2 = 3.2 × 10^-20 m2/W. These mean that high accuracy as well as large-scale nonlinear refractive index measurement can be achieved by the proposed approach.

Fabrication and Measurement of Organic Waveguide

A composite waveguide of 4-butoxycarbonylmethylurethane polydiacetylene has been fabricated. By measuring the change with optical intensity in the coupling angle between input laser beam and a planar waveguide mode in the structure, we estimated that the intensity-dependent index of refraction (n2) approximately equals -1.9×10-7 (MW/cm2)-1.

Dynamical Behavior of Solution in Integrable Nonlocal Lakshmanan–Porsezian–Daniel Equation

The integrable nonlocal Lakshmanan–Porsezian–Daniel(LPD) equation which has the higher-order terms(dispersions and nonlinear effects) is first introduced. We demonstrate the integrability of the nonlocal LPD equation,provide its Lax pair, and present its rational soliton solutions and self-potential function by using the degenerate Darboux transformation. From the numerical plots of solutions, the compression effects of the real refractive index profile and the gain-or-loss distribution produced by δ are discussed.