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The third order nonlinear optical properties i.e. nonlinear refraction (n 2), absorption coefficient (β) and third order susceptibility χ(3) of glycine zinc sulphate pentahydrate (GZS) semi-organic single crystal was investigated under the excitation of Q-switched Nd-YAG laser pulsed radiations (λ = 532 nm & 1064 nm) by familiar Z-scan method. The values of nonlinear refraction (n 2), at 532 nm were 1.19 × 10−5 (cm2/GW), 2.09 × 10−5 (cm2/GW), 2.27 × 10−5 (cm2/GW), 2.48 × 10−5 (cm2/GW), and 2.55 × 10−5 (cm2/GW) at incident optical beam intensities of 0.76 (GW/cm2), 1.13 (GW/cm2), 1.17 (GW/cm2), 1.63 (GW/cm2) and 1.88 (GW/cm2) respectively while that of values at 1064 nm were 4.31 × 10−5 (cm2/GW), 4.69 × 10−5 (cm2/GW), 5.41 × 10−5 (cm2/GW) and 6.39 × 10−5 (cm2/GW) at incident optical beam intensities of 1.20 (GW/cm2), 1.25 (GW/cm2), 1.32 (GW/cm2) and 1.38 (GW/cm2) respectively. The values of nonlinear absorption coefficient (β) at 532 nm were −1.45 (cm/GW), −0.79 (cm/GW), −0.5 (cm/GW), 0.12 (cm/GW) and 0.64 (cm/GW) at incident optical beam intensities of 0.76 (GW/cm2), 1.13 (GW/cm2), 1.17 (GW/cm2), 1.63 (GW/cm2) and 1.88 (GW/cm2) respectively while that of values at 1064 nm were 0.62 (cm/GW), 0.74 (cm/GW), 0.77 (cm/GW) and 0.81 (cm/GW) at incident optical beam intensities of 1.20 (GW/cm2), 1.25 (GW/cm2), 1.32 (GW/cm2) and 1.38 (GW/cm2) respectively. The values of third order susceptibilities χ(3) at 532 nm were 0.83 × 10−12 (esu), 1.32 × 10−12 (esu), 1.42 × 10−12 (esu), 1.55 × 10−12 (esu) and 1.56 × 10−12 (esu) at intensities of 0.76 (GW/cm2), 1.13 (GW/cm2), 1.17 (GW/cm2), 1.63 (GW/cm2) and 1.88 (GW/cm2) respectively while that of values at 1064 nm were 2.71 × 10−12 (esu), 2.96 × 10−12 (esu), 3.4 × 10−12 (esu) and 4.02 × 10−12 (esu) at incident optical beam intensities of 1.20 (GW/cm2), 1.25 (GW/cm2), 1.32 (GW/cm2) and 1.38 (GW/cm2) respectively. It was seen that the sample showing saturable absorber to reverse saturable absorber at 532 nm wavelength at incident optical beam peak intensity (I 0) of 1.53 GW/cm2. Thus the crystal could be a potential candidate of optical switching application. It was also seen that the material possess positive nonlinearity. It was also found that the values of nonlinear absorption coefficient (β) and nonlinear refraction (n 2) increase with increase of excitation intensity irrespective of excitation wavelengths. [ABSTRACT FROM AUTHOR]

• Third order nonlinear optical properties were studied for novel quinoxalines molecules. • Linear optical properties were investigated using TD-DFT calculations and absorption spectroscopy. • The highest values for χ (3), χ & n 2 are obtained for the PQ-a derivative. • χ (3) = 4.35 × 10−14 esu, χ = 4.41 × 10−31 esu, and n 2 = 8.44 × 10−16 cm2/W. We report our results from the investigations of linear and ultrafast nonlinear optical properties of a set of pyrrolo[1,2-a]quinoxalines. Using the steady state optical techniques and density functional theory calculations the linear optical properties were investigated while the non-resonant ultrafast nonlinear optical properties were studied using the degenerate four-wave mixing technique at a wavelength of 800 nm with 70 fs pulses. The investigated molecules demonstrated large off-resonant second hyperpolarizability (γ) and nonlinear refractive index (n 2) values compared to similar molecular moieties with potential application in optical devices. [ABSTRACT FROM AUTHOR]

Abstract Luminescent, water soluble, CdTe colloidal QDs were synthesized by simple wet chemical method. The prepared CdTe QD samples were showing wide range of color tunability from green to red when irradiated with UV light. The quantum confinement effect of the synthesized QDs was confirmed using UV–vis absorption and fluorescence spectroscopy. The spherical morphology of the synthesized QDs was confirmed using transmission electron microscopy (TEM). The X-ray diffraction (XRD) analysis indicates that the QDs were having cubic structure. Analysis of the third order nonlinear property using Z-scan technique indicates that the QDs were having two photon absorption properties. Unlike the previous reported results, the variations in the third order nonlinear susceptibility (χ 3) was found to be in correlation with emission intensity. The value of imaginary part of nonlinear χ 3 and refractive index was found to be of the order of 10−11 and 10-7esu respectively. Imaginary part of χ 3 is found to be Gaussian dependent function of reaction time, which provides a possible way of tuning of imaginary part of third order susceptibility. The figure of merit (n 2 /β) of the synthesized QDs was found to be greater than that for the bulk material. Thus these QDs possess good nonlinear optical characteristics which enable them as a potential candidate for the optical limiting application. [ABSTRACT FROM AUTHOR]

Abstract Third order nonlinear material of 4-[(1 E)-3-(5-chlorothiophen-2-yl)-3-oxoprop-1-en-1-yl]phenyl4-methylbenzene-1-sulfonate (4 TP MS) was synthesized by Claisen Schmidt condensation reaction method and single crystals were grown by slow evaporation technique. The functional groups corresponding to the vibrational frequencies has been confirmed through FT-IR and FT-RAMAN spectroscopic techniques. The single crystal XRD analysis revealed the crystal is belonging to monoclinic crystal structure with P 2 1 / n space group. The optical properties were studied by UV-VIS spectroscopy and photoluminescence spectroscopy. The cut-off wavelength of 4 TPMS is found to be 432 nm and the crystal is transparent in entire visible and near IR region. Using absorbance data, the parameters like extinction co-efficient, reflectance, electrical conductivity, optical conductivity, complex dielectric constant, lattice dielectric constant and ratio of carrier concentration to effective mass has been analyzed. The crystal has blue light emission property with less defects were observed from photoluminescence studies. The 4 TPMS is thermally stable up to 254 °C. The dielectric properties like dielectric constant and dielectric loss were studied. The low value dielectric loss at high frequency region enhances the optical quality of the material. The third order nonlinear properties of nonlinear absorption and nonlinear refraction were studied through open/closed aperture Z-Scan technique. The high value nonlinear absorption co-efficient of 4 TPMS makes the material suitable for optical limiting application. These optical limiting properties were extracted from open aperture Z-Scan data and this behavior is due to reverse saturable absorption. The large value of third order nonlinear susceptibility is of the order of 10 − 11 esu and material has better capability to be used optical device applications. Graphical abstract Image 1 Highlights • The 4 TPMS crystals were grown by solution evaporation technique. • The structural, optical, electrical and nonlinear optical properties were discussed. • The low dielectric constant and low dielectric loss enhances the optical quality of the material. • The 4 TPMS molecule has extended conjugation length (D-π-A-π-D). This phenomenon enhanced the value of nonlinear absorption coefficient. • The measurement of third order nonlinear susceptibility (10−11 esu) is interesting in the present investigations. [ABSTRACT FROM AUTHOR]

Transparent Alkaline Bismuth Borate glasses (10RO-35Bi 2 O 3 -55B 2 O 3 , where R = Ba, Ca & Sr) were prepared by melt-quenching method. The optical band gap values of the glasses are obtained from absorption spectra and found to increase due to the presence of alkaline earth ion in the order of Ba < Sr < Ca whereas optical basicity values follows the reverse trend. Nonlinear optical properties and optical limiting properties of the glasses were investigated at wavelengths of 532 and 800 nm for ns and ps and fs time domains respectively by Z-scan technique. Two-photon absorption is regarded as the dominant mechanism in the case of Sr and Ca based glasses whereas glass with Ba exhibit two photon induced three photon mechanism. Optical limiting characteristics are also reported in fs and ns regimes for these glasses. [ABSTRACT FROM AUTHOR]

Third order nonlinear optical properties of organic crystal L-threoninium P-toluenesulfonate monohydrate was investigated by 'Z-scan' technique employing two different laser sources under different intensities at 532 nm CW laser and 1064 nm pulsed laser respectively. Nonlinear absorption coefficient (α NL) and nonlinear refraction (n 2) were evaluated at six different intensities using 532 nm CW laser source and with pulsed laser source (λ = 1064 nm) by changing the pulse rate keeping intensity same. It is found that this crystal possesses positive nonlinearity and exhibit saturation absorption. • NLA coefficient (β) and NLR (n 2) of L-threoninium P-toluenesulfonate monohydrate organic single crystal using two laser sources at 532 nm and 1064 nm. • It is found that this crystal possess positive nonlinearity and exhibit saturation absorption. • The nonlinear absorption of this crystal found to be negative. • This crystal may be useful in optical switching application. [ABSTRACT FROM AUTHOR]

The linear and nonlinear optical properties of polymer/inorganic nanocomposites have received a great interest because of their potential application such as optical limiting devices. A flexible foil like polymer/ZnO nanocomposites and polymer/ZnO/CuO nanocomposites have been prepared via casting method. ZnO and CuO nanoparticles were used as filler, while four different types of polymer were used as polymer matrix. The purity and composition of the nanocomposites were confirmed via EDX analysis and EDS mapping. Surface morphology of samples was tested by FESEM that were shown the dispersion of ZnO and CuO nanoparticles successfully. To study the influence of adding CuO nanoparticles on polymer/ZnO nanocomposites; the liner transmittance was measured and linear absorption coefficient was calculated. The results show a decrease in linear transmittance and increase in linear absorption coefficient when CuO nanoparticles was added. Then, the absorption coefficient and refractive index of the as-prepared sample were analysed using an open and closed aperture single beam Z-scan technique via Q-switched Nd-YAG pulse laser at 532 nm. The nonlinear refractive index was in the order of 10 cm/W with a negative sign whereas the nonlinear absorption coefficient was in the order of 10 cm/W. The real part, imaginary part and the absolute value of the third order nonlinear optical susceptibility χ were calculated. The χ was in the order of 10 esu. The effect of adding CuO nanoparticles to nanocomposites was enhanced their nonlinear optical properties. Consequently, a good optical limiting was obtained. The optical limiting threshold of the samples was measured. The results showed that the prepared nanocomposites can be considered as an excellent candidate for optical limiting devices, which clearly affected by the adding CuO nanoparticles and the type of polymer matrix. Nanocomposites PMMA/ZnO/CuO and PS/ZnO/CuO showed the low optical limiting threshold, which were equal to 60 and 50 Mw/cm, respectively. [ABSTRACT FROM AUTHOR]

Ammonium d , l -Tartrate (AMT) single crystal for optical and photonic device application was analyzed with different characterization studies. The AMT crystal was grown by low cost conventional solution growth technique. The unit cell parameters were obtained from single crystal XRD analysis and the crystal system is confirmed to be orthorhombic with noncentrosymmetric space group P2 1 2 1 2 1 . The crystalline perfection evaluated by high resolution X-ray diffractometry (HRXRD) enumerates the quality of the crystal is good. The optical transparency window of AMT crystal has 78% transmittance from 234 nm to 1100 nm region and has lower cut-off wavelength of 234 nm was analyzed by UV–visible spectral studies. The hardness number (H v ) , yield strength (σ y ) and elastic stiffness constant (C 11 ) were evaluated from the hardness data using Vickers hardness tester. Dielectric study indicates the moderate dielectric constant and low dielectric loss of AMT crystal which are required properties to develop optoelectronic devices. The laser damage threshold value of AMT is 0.238 GW/cm 2 and photoconductivity study reveals the positive photoconductivity nature of the AMT crystal. The particle size dependent SHG studies were performed using Nd:YAG laser. The SHG efficiency of AMT is found to be 1.3 times greater than the standard KDP crystal. Third order nonlinear susceptibility χ (3) of AMT was assessed using an open aperture and closed aperture Z-scan technique and the value is 6.71×10 −6 esu. AMT crystal is found to exhibit good optical power limiting. The present work indicates that AMT is a potential material for optoelectronic and nonlinear optical devices. [ABSTRACT FROM AUTHOR]

Nonlinear optical properties have received great interests by experimentalists due to a wide range of applications in the optical devices. In the current work, the polymethyl methacrylate (PMMA)/ZnO nanocomposites have prepared as foils by using casting method. Nanocomposites have prepared by mixing the different concentrations of ZnO nanoparticles as filler with PMMA as polymer matrix. Linear transmittance spectra have investigated and linear absorption coefficients have calculated. The nonlinear refractive index and nonlinear absorption coefficient have explored by using a single beam z-scan technique, Q-switched Nd-YAG pulse laser use as the light source. The transmittance shows decrease with the increase of the ZnO nanoparticles concentration. The samples have shown peak absorption at 375 nm. The nonlinear refractive index is in the order of 10 cm/W with the negative sign, whereas the nonlinear absorption coefficient is in the order of 10 cm/W. The real, imaginary parts and absolute value of the third-order nonlinear optical susceptibility χ have calculated. χ is in the order of 10 e.s.u. Hence, those nanocomposites indicate a promising candidate to be used as an optical limiter. [ABSTRACT FROM AUTHOR]

Single crystals of semiorganic sodium hydrogen maleate trihydrate (SHMT) were effectively grown from deionized water by solvent evaporation technique. The grown crystals were subjected to single crystal X-ray diffraction to know the precise information about the crystallographic structure. The SHMT crystal belongs to triclinic system with centrosymmetric space group of P-1. TGA/DTA analysis indicates that the grown crystal was thermally stable up to 249.6 °C. The UV–Visible spectrum revealed its high transparency nature and the cut off wavelength was found to be at 290 nm. Its mechanical behavior was assessed by Vickers microhardness measurements. Dielectric measurements were made over a wide range of frequency (50 Hz–1 MHz) at room temperature. Theoretical calculations for polarizability and optical constants were made which are necessary for device fabrication. The third-order nonlinear optical parameters were derived by Z-scan technique. The third-order nonlinear refractive index, absorption coefficient and susceptibility values were found to be −5.04112 × 10 −11 cm 2 /W, 1.08717 × 10 −3 cm/W and 6.35585 × 10 −7 esu respectively. [ABSTRACT FROM AUTHOR]

The preparation and NLO characterization of photosensitive polyesters containing azoaromatic residues in the molecular backbone, functionalized with orthohydroxy chromophores is presented. Samples were studied for its UV–vis absorption, FT-IR and intensity dependent nonlinear absorption properties. Nonlinear characterization was carried out with z-scan using frequency doubled, Q-switched Nd:YAG laser operating at 532 nm. The closed aperture z-scan spectra reveal the self defocusing effects of the samples with negative nonlinearity coefficient ( n 2 ) showing values as high as −1.28 × 10 −10 (esu) for certain samples and the corresponding third order susceptibility coefficient of the order of 29.9 × 10 −12 (esu). Degenerate four wave mixing technique was employed to substantiate the findings. The numerical fits show that the molecules exhibit reverse saturable absorption. A study of beam fluence dependence of nonlinear absorption coefficient ( β eff ) has been presented. All phenomena indicate that molecules are reverse saturable absorbers whose optical limiting property gets enhanced with increasing conjugation length. [ABSTRACT FROM AUTHOR]

Natural dyes with highly delocalized π-electron systems are considered as promising organic materials for nonlinear optical applications. Among these dyes, Bixa Orellana dye with extended π-electron delocalization is one of the most attractive dyes. Bixa Orellana dye-doped Poly(methyl methacrylate) (PMMA) thin films were prepared through spin coating process for linear and nonlinear optical properties investigation. Atomic force microscopy (AFM) was used to evaluate the roughness of the thin films. The optical constants n and k were evaluated by ellipsometric spectroscopy. The refractive index had a maximum of about 1.456 at 508.5, 523.79 and 511.9 nm, while the maximum of k varies from 0.070 to 0.080 with the thickness. The third order nonlinear optical properties of the hybrid Bixa Orellana dye-PMMA polymer were investigated under 30 ps laser irradiation at 1064 nm with a repetition rate of 10 Hz. In particular the third-order nonlinear susceptibility has been determined by means of the Maker Fringes technique. The nonlinear third order susceptibility was found to be 1.00 × 10 −21 m 2 V −2 or 0.72 × 10 −13 esu. Our studies provide concrete evidence that the hybrid-PMMA composites of Bixa dye are prospective candidates for nonlinear material applications. [ABSTRACT FROM AUTHOR]

The spatial evolution of nonlinear wave groups with the same initial Gaussian envelope are theoretically studied under different kind of governing equations, confirming that the higher order nonlinear Schrödinger equation formulation of Dysthe is capable of representing the asymmetric features of propagating wave packets which have narrow spectral bandwidth in deep water. Moreover, laboratory experiments run in an offshore wave basin are systematically compared with a large set of numerical simulations, respectively performed by using the third-order and fourth-order nonlinear wave models, mainly focusing on the aspects of higher order statistical moments such as the coefficients of skewness and kurtosis of the surface elevation, and the exceedance distributions of wave heights in different random sea states. The modulational instability, resulting from a quasi-resonant four wave interaction in the unidirectional sea state, can be indicated by the coefficient of kurtosis, which has shown an appreciable correlation with the abnormal wave density from a statistical point of view. Compared with Dysthe simulation, the NLS model presents a more intensive energy focusing, particularly at the intermediate stage of evolution process in the presence of strong nonlinearity. [ABSTRACT FROM AUTHOR]

A novel approach for phototherapy is proposed. The proposed method is based on cell apoptosis according to halting activation of cancer cell membrane receptor by exposure to UV light pulses without any side effect. In the proposed method, gold nanoparticles are directed to cancerous cells by conjugating their surface with specific ligands. UV light is created locally adjacent to cells around the gold nanoparticles. UV light is generated due to nonlinear interaction of visible light with gold nanoparticles because of enhancement in third order nonlinear effects. For example, by using 780 nm laser, 260 nm UV will be generated around the nanoparticle because of third harmonic generation process. As the generated UV is localized around the cell, there will be no side effect for other cells. We have numerically analyzed the proposed method by solving Maxwell's equation considering third order nonlinear susceptibility and dispersion behavior of permittivity by 3D nonlinear finite difference time domain using Newton-Raphson method. Simulation results for different geometries show that UV light will be generated around gold nanoparticle and it is maximum in hot spots where electric field enhancement occurs. Simulation results illustrate that there is neither UV irradiation side effect to healthy cells, nor harmful temperature rise. [ABSTRACT FROM AUTHOR]

The rth-order nonlinearity, where r ≥ 1, of an n-variable Boolean function f, denoted by nl r ( f), is defined as the minimum Hamming distance of f from all n-variable Boolean functions of degrees at most r. In this paper we obtain a lower bound of the third-order nonlinearities of Kasami functions of the form $Tr_{1}^{n}(\mu x^{57})$ . It is demonstrated that for large values of n the lower bound of the third-order nonlinearities of the functions of this form is larger than the general lower bound obtained by Carlet (IEEE Trans Inf Theory 54(3):1262–1272, 2008) for Kasami functions. Further we show that our result along with the computational results obtained by Fourquet and Tavernier (Designs Codes Cryptogr 49:323–340, 2008) provide us an estimate of the nonlinearity profiles of these functions for n = 7, 8, 10. [ABSTRACT FROM AUTHOR]

Abstract: A tunable filter with multichannel is proposed based on a nonlinear ferroelectric photonic crystal made of rhodium doped barium titanate. The filtering properties of the photonic crystal filter, including channel number and frequency, can be tuned by adjusting the thickness of defect layer or by pump light. The dynamical shift of channels with pump intensity is studied in detail. The channel shifts about 90nm under the excitation of 75MW/cm2 pump light. The influences of structural disorders caused by random perturbations in the thickness of dielectric layer or air layer on the photonic crystal filter are analyzed. [Copyright &y& Elsevier]

An optical switching is proposed, which is based on two dimensional nonlinear photonic crystal made of cerium doped barium titanate, and can work in the visible or infrared waveband. The optical nonlinearity originates from the delocalization of the titanium ions in the center of TiO6 octahedrons. The dynamical shift of the photonic bandgap with pump intensity is calculated on the basis of the optical Kerr effect. It is found that the pump light of 6.7 GW/cm2 can changes the transmittance of the probe light from 0% to 95% for the first sample in the visible waveband and from 0% to 92% for the second sample in the infrared waveband, respectively. The influences of the disorders caused by the random perturbations in the diameter or the position of the air hole on the optical switching are analyzed. [Copyright &y& Elsevier]

Synthesis of hydrazine hydrate assisted manganese doped zinc selenides by hydrothermal technique led to the formation of good quality nanospheres which are controlled by Ostwald ripening process. Structural studies using XRD showed the incorporation of manganese in zinc selenide matrix with their crystallite sizes ranging between 10 and 15 nm, which corroborate with the TEM measurements. Dominant emission (517 nm) corresponds to the near band edge emission as observed from photoluminescence spectra. Presence of impurities and defects were identified from various other emissions as well as from the bandgap variation obtained from reflectance spectra. The third order nonlinearity of manganese doped zinc selenide nanoparticles were calculated by the standard Z-scan technique using 532 nm CW DPSS and nanopulsed Nd:YAG laser. Mn doped ZnSe nanoparticles which exhibits near resonant excited state absorption were found to be an ideal candidate to be exploited as optical limiters in protecting optical components from high intense laser pulses. Further, lower onset optical limiting threshold under pulsed laser excitation of manganese doped zinc selenides (2.92 × 1012 Wm−2) compared to pure zinc selenide (4.98 × 1012 Wm−2) confirms that doping of Mn in ZnSe can yield efficient energy absorbing optical limiters. Image 1 • Mn2+ doped ZnSe nanoparticles were synthesized by hydrothermal method. • Ostwald ripening process leads to the formation of spherical nanoparticles. • Structural, linear and nonlinear optical properties are studied. • Third order nonlinearity of the synthesized nanoparticles was studied by Z-scan technique using both CW and pulsed lasers. • Optical limiting studies reveal that the synthesized nanoparticles can be exploited as good optical limiters. [ABSTRACT FROM AUTHOR]

Here, we report the role of different stabilizers (Eu 2 O 3 , EuF 3 and KSCN) in stabilizing gold nanoparticles (AuNPs) embedded in Bismuth-Borosilicate glasses. The prepared nanocomposites are characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), UV–Visible transmission spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), ellipsometery and Z-scan. From FESEM, it has been observed that the morphology of AuNPs is highly dependent on the type of stabilizer. Also HRTEM confirms the covering of AuNPs by stabilizer that prevents the coagulation of NPs. The localized surface plasmon resonance related transmission dip is observed around 585 nm for glass containing Eu 2 O 3 as a stabilizer. The linear and nonlinear refractive index of the prepared glasses is obtained from ellipsometery and Z-scan measurements, respectively. All the Z-scan measurements have been carried out at different input peak intensities varying from 1.9 to 14.38 GW/cm2. Nonlinear optical studies with open aperture Z-Scan shows the switching between saturable absorption and two photon absorption as the laser intensity is increased. The existence of third order nonlinearity has been detected using closed aperture Z-scan in the prepared glasses. • Gold nanoparticles embedded in Bismuth borosilicate glasses stabilized by Eu 2 O 3 , EuF 3 and KSCN. • Up to Third order non-linearity is observed in closed aperture Z-scan. • High refractive index in UV-VIS-NIR observed in ellipsometery measurements. • Prepared glasses having potential applicant for long range surface plasmon resonance sensors. [ABSTRACT FROM AUTHOR]