Third-order Nonlinear Properties Research Articles

Synthesis, growth, optical, thermal, electrical and third-order nonlinear properties of an organic single crystal guanidinium 3,5 dinitrosalicylate: A promising candidate for nonlinear optical applications

An organic single crystal guanidinium 3,5 dinitrosalicylate (GuDNS) was successfully grown using slow evaporation technique. The cell parameters of the GuDNS crystal were found using powder X-ray diffraction study. The UV–vis–NIR transmittance study of the titular crystal was analyzed and other optical constants such as extinction coefficient, reflectance, electrical conductivity, optical conductivity were also calculated. The emission spectrum of GuDNS single crystal was determined using photoluminescence study. Using TG-DTA spectrum, the thermal stability of GuDNS crystal was analyzed. The mechanical property of GuDNS crystal was examined using Vicker's microhardness analysis. The electrical properties such as dielectric constant and dielectric loss were recorded for different temperatures with varying frequencies. The third order nonlinear susceptibility of GuDNS crystal was found using Z-scan technique. The obtained results show that the grown GuDNS crystal could be a promising candidate for nonlinear optical applications.

Electric Field Effects on Neutral Gold Clusters Au<sub>2-10</sub>: A First-Principles Theoretical Survey of the First- and Second-Order Hyperpolarizabilities

Herein we report the density functional theory (DFT) calculations of nonlinear optical (NLO) properties of neutral gold clusters Aun (n=2-10) applying long-range corrected LC-M06L functional and Los-Alamos National Laboratory double-ζ polarized basis set. The effects of the incident frequency on the first and second-order hyperpolarizability together with the influence of the external electric field on the frontier orbitals of neutral gold clusters are investigated. It is found that the application of external electric field can increase or decrease the gap energy of neutral gold clusters depending on the direction and magnitude of the applied field. More importantly, by correctly controlling the direction and magnitude of the external electric field, reactive gold clusters having low gap energies can be achieved. Furthermore, the external electric field has more important effect on the virtual orbitals of gold hexamer and decreases the energy of these orbitals along the directions parallel to the molecular plane, resulting in low-energy excitations. The low-energy excitations are expected to play important role in the high second-order hyperpolarizability and better response to the applied field. The third-order nonlinear (NLO) properties of gold hexamer are also strongly affected by the frequency of the incident light and thus can be tuned using the incident frequency for applications. The present work may propose new strategies for enhancing the nonlinear optical response of neutral gold clusters.

Third-order optical nonlinear properties of Co-doped V2O5 nanoparticles

The Co-doped vanadium pentoxide nanoparticles with Co concentrations up to 20 wt. % were synthesized via a gelatin-based sol–gel route. The effect of Co substitution was investigated on the microstructural and nonlinear optical characteristics of the synthesized particles through X-ray diffraction, field effect scanning electron microscopy and Z-scan technique. The results showed that the synthesized particles consist mainly of crystalline α-V 2 O 5 phase. Co substitution results in expansion of the orthorhombic unit cell and growth of particle size from about 36–45 nm. On increasing the dopant concentration, the nonlinearity was enhanced due of the improved crystallinity, more porosity, and the increased carrier concentration. The optical nonlinearity was intensified by the power of incident laser radiation, as well. The nonlinear refractive (NLR) index, nonlinear absorption (NLA) coefficient, and nonlinear optical susceptibility are of 10 − 8 ( c m 2 / W ) , 10 − 4 ( c m / W ) , and 10 − 8 ( c m 2 / W ) order, respectively. The positive NLR index of samples originates from the self-focusing effect. Furthermore, the involved NLA coefficients are mainly related to the saturable absorption. The encouraging nonlinear optical results of V 2-x Co x O 5 suggests that this system is a promising candidate for nonlinear optical applications.

Improvement of third-order nonlinear properties in GeS2–Sb2S3–CsCl chalcogenide glass ceramics embedded with CsCl nano-crystals

We studied the third-order nonlinear (TONL at 0.8 μm) properties of the chalcogenide glass-ceramic within the GeS2-Sb2S3–CsCl system, and found that the nano-crystallization of CsCl phase in the glass matrix could enhance the TONL properties significantly. As compared to the parent glass without crystallization, the maximum nonlinear refractive index (n2) of the GeS2-Sb2S3–CsCl chalcogenide glass ceramics is nearly tripled, while the maximum nonlinear absorption coefficient (β) is also increased by 62%. The calculation of figure of merits (FOMs) ascertained that glass ceramics embedded with smaller CsCl crystallites tend to have better TONL performance.

The photochromic, electrochemical and third-order nonlinear optical properties of the novel naphthopyran derivatives

A series of novel naphthopyran derivatives featuring nonplanar and spiro-conjugation structure have been successfully synthesized and characterized. In this paper, we investigated the effects of the electron donating ability and volume of substituents on the photochromic and third-order nonlinear properties of novel naphthopyran derivatives. The UV–Vis absorption spectroscopy was used to analyse the photophysical and photochromic properties. Under the dual role of electron-donating group and bulky substituent group, maximum absorption peaks (λmax) of the closed form and the open-form of the naphthopyran derivatives were both red shifted, and all molecules showed relatively good photochromic properties and fatigue resistance. The electrochemical properties have been investigated by the cyclic voltammetry (CV) measurement, the band gap of NP-C, NP-O and NP-N narrowed in sequence, and the level of HOMO decreased in turn. The third-order nonlinear optical (NLO) properties of the compounds were studied by the Z-scan techniques at 532 nm, which indicated that all molecules showed the reverse saturable absorption (RSA) behavior and the optical susceptibility χ(3) reached 10−14. These interesting findings provide a new insight on the practical application of naphthopyran molecules and the design of the NLO materials.

Nonlinear optical properties of peripheral symmetrically and non-symmetrically 4-(trifluoromethoxy)phenoxy substituted zinc phthalocyanines

In this work, new non-symmetrical, peripherally substituted metallophthalocyanines, namely 2(3)-[(4-nitrophenyl)ethynyl]-{9,10,16,17,23,24-hexakis-(4-(trifluoromethoxy)phenoxy)-phthalocyaninato}zinc (1b) and 2(3)-[(4-nitrophenyl)ethynyl]-{9(10),16(17),23(24)-tris-(4-(trifluoromethoxy)phenoxy)-phthalocyaninato}zinc (2b) were prepared. Structural elucidation of the novel zinc phthalocyanines was carried out with well-known spectroscopic methods. The solubility of the phthalocyanines was investigated in organic solvents like tetrahydrofuran, dichloromethane, and dimethyl sulfoxide. The effect of concentration on aggregation behavior of the resulting phthalocyanines (1b and 2b) was examined in a wide area ranging from 4 × 10−6 to 14 × 10−6 M in tetrahydrofuran. Aggregation properties of the macrocyclic molecules (1b and 2b) were also investigated in many organic solvents. Based on the data existing in the literature, peripherally octa- and tetra-substituted zinc phthalocyanines (1a and 2a) with 4-(trifluoromethoxy)phenoxy moieties were synthesized. Optical limiting and the third-order nonlinear properties of symmetrically and non-symmetrically substituted phthalocyanines were determined and compared with each other.

Optical limiting behaviour of linear fused ring dichloro-substituent chalcone isomers

The third-order nonlinear optical response of halogen anthracenyl chalcone isomers in dimethyl sulphonate (DMSO) as the solvent has been studied. Single beam Z-scan technique at 532nm of laser excitation wavelength is used to determine magnitude and sign of the nonlinear refractive index (n2) and nonlinear absorption coefficient (β). The samples exhibited a self-focusing effect with a negative from the closed aperture z-scan analysis. The n2 is observed to be 10−8 cm2/W. Open z-scan data showed reverse saturable absorptions with significant β for both samples. The magnitude of β is of the order of 10−4 cm/W. Optical limiting studies show a decrement in transmittance as a function of input fluence. Optical limiting action begins at as low as 20 kW/cm2 of focal input intensity which is ideal for low powered continuous wave laser limiting applications. From the third-order nonlinear properties results, the compound is recommended for optoelectronic and photonics application.

Enhanced optical, mechanical, photoacoustic and third-order nonlinear property of pure and crystal violet (CV) dye incorporated anthracene crystal: an efficacious material for nonlinear optical applications

Single crystals of pure and crystal violet (CV) dye-doped anthracene single crystals have been synthesized by solvent evaporation technique utilizing chloroform as the solvent. There is a significant enhancement in optical, mechanical, photoacoustical and third-order non-linear properties have been attained due to the incorporation of dye in the host material. The unit cell parameters and crystallinity of the grown crystals were examined using single crystal and powder crystal XRD analysis. The presence of various functional groups and mode of vibrational frequencies present in the grown crystal is determined using FTIR spectra. The doped crystal exhibits high optical transparency than pure which is evident in UV–Visible spectrum. Using Knoop hardness study the Young’s modulus value of pure and doped crystal is found to be 1.154 × 1010 Nm−2 and 1.394 × 1010 Nm−2. Doping of CV dye results in the enhancement of hardness number and various hardness parameters such as brittleness index, elastic stiffness constant and fracture toughness are calculated using Vicker’s microhardness study. Photoacoustic study depicts the thermal diffusivity value for the grown crystals and it is found to be 1.2505 × 10–6 and 3.128 × 10–6 for undoped and doped crystal respectively. The real, imaginary and third-order susceptibility of the doped crystal is prominent than undoped crystal were elucidated using Z-scan study.

Comments on the paper ‘Co-crystals of urea and hexanedioic acid with third-order nonlinear properties: An experimental and theoretical enquiry’

The authors of a recent paper (J. Mol Struc. 1202 (2020) 127237) claim to have grown a so-called ‘urea hexanedioic acid’ (UHA) cocrystal by the slow evaporation of an aqueous solution containing equimolar amounts of urea and hexanedioic acid. In this comment, many points of criticism, concerning the crystal growth, single crystal data, IR spectrum and theoretical study of the so called UHA crystal are highlighted to prove that the title paper is completely erroneous.

Zinc Phthalocyanine-Poly (Vinyl Alcohol) nanocomposite films: Low threshold optical limiting properties based on third-order nonlinear absorption response

In this article, we discuss on an in-depth study of the structure and morphology as well as optical (linear/nonlinear) properties of Zinc Phthalocyanine (ZnPc) - Poly (Vinyl Alcohol) (PVA) nanocomposite films. An investigation into the third-order nonlinear absorption properties of the nanocomposite films of ZnPc-PVA system, on excitation with low power continuous wave (CW) laser light at 632.8 nm, for different concentrations of the ZnPc content and at different input intensities, is presented. In these nanocomposites, a transition from Saturable Absorption (SA) to Reverse Saturable Absorption (RSA) was observed, on either increasing fluence or ZnPc content. The estimated values of the effective coefficients of nonlinear absorption (β) and imaginary third-order nonlinear susceptibility (Imχ(3)) are better than those reported ones. Furthermore, the optical limiting action of these samples is demonstrated. The results suggest that the nanoclustered organic chromophores are dispersed uniformly in the voids/free volumes available between the PVA chains. Standing on these points, it may be noted that the newly fabricated ZnPc-PVA nanocomposite films, which possess excellent surface homogeneity, high laser damage threshold, improved thermal and photostability, and prolonged lifespan (five years or more!), represent an efficient low threshold NLO material with significant potential applications in optoelectronic and photonic devices.

Third-order Nonlinear Dispersion Properties of Surface Plasmon Resonance in Gold Nanoparticles

Third-order Nonlinear Dispersion Properties of Surface Plasmon Resonance in Gold Nanoparticles

Investigation on growth, structural, dielectric, optical and third-order optical nonlinear properties of 8-hydroxyquinolinium 4-chloro-3-nitrobenzoate 4-chloro-3-nitrobenzoic acid crystal

An organic 8-hydroxyquinolinium 4-chloro-3-nitrobenzoate 4-chloro-3-nitrobenzoic acid (8-HQCN) was synthesized and the crystals were grown by employing solution growth method. Single crystal XRD data revealed crystal system (monoclinic, space group P21/n), and cell dimensions (a = 6.9806(2) Å, b = 11.9919(4) Å, c = 26.8872(8) Å). The FT-IR, FT-Raman and NMR spectral analyses provide the molecular structure. UV–visible spectrum provides a band gap (3.03 eV) and cut off wavelength (404 nm) of the crystal. The broad emission at 580 nm in PL spectrum reveals the suitability of the material yellow light emission. Vicker’s microhardness study gives the mechanical stability of the grown crystal. The nonlinear optical susceptibility (χ(3)) of the molecule was calculated as 16.78 × 10−6 esu from Z- scan technique and from DFT theory it was calculated to be 5.632 × 10−6esu using cam-b3lyp/6–311G (d, p). Thermo-optic coefficient of 8-HQCN was predicted to be 3.805 × 10−6 K−1 by thermal conductivity studies. This thermally prompted defocusing character can be made useful in optical limiters. The thermal investigation exhibits the bearing proficiency of 8-HQCN to be 127 °C. The orbital energy, band gap and the second hyperpolarizability were also studied by varying the applied field. The dispersion of the dielectric constant illustrates the usual behavior and the enhanced quality of the material gives the low dielectric loss. Antibacterial studies were taken to check the resistance to harmful bacteria of the grown crystal.

Co-crystals of urea and hexanedioic acid with third-order nonlinear properties: An experimental and theoretical enquiry

Abstract Urea-adipic acid (UHA) co-crystal was synthesized and harvested at room temperature by the slow evaporation method. The single X-Ray diffraction of the crystal system and its lattice parameters of the UHA co-crystal were determined. The functional nature of the compound was analyzed using FT-IR and FT-Raman spectra. By the UV–Vis spectrum, the optical transmission property was estimated and the mechanical stability was found by Vickers microhardness experiment. Further, the thermal stability and melting point was studied by TG/DSC methods. In the range of frequencies 50 Hz -5 MHz at different temperatures 313 K, 333 K, 353 K, and 373 K the crystal dielectric behavior has been observed. Fluorescence study and lifetime-resolved decay computation were also performed. The SEM picture rendered the surface morphology of UHA crystal. The structural properties of the UHA crystal were computed utilizing the CAM-B3LYP method and 6–311++G(d,p) basis set and found agreeable with the experiment data (XRD). The linear polarizability ( α ) and hyperpolarizability (β) of first-order have also been determined. The HOMO and LUMO (bandgap) energies, molecular electrostatic potential and Non-linear optics (NLO) explain the chemical activity of the UHA confirming the advantage of the material. The UHA nonlinear optical characteristics of third-order have been analyzed by the Z-scan technique.

Effect of solvents on the nonlinear optical behavior and spectral findings of bis [4-(dimethylamino) phenyl] methaniminium chloride

Molecular structure, vibrational features and nonlinear optical properties of the dye bis [4-(dimethylamino) phenyl] methaniminium chloride have been studied. The detailed structural and optical properties were studied by spectroscopic techniques such as FT-IR, FT-Raman, UV–visible combined with theoretical DFT method. Using the Z-scan technique, third-order nonlinear properties like nonlinear absorption, nonlinear refraction, third-order susceptibility and second-order hyperpolarizability were measured experimentally in different solvents with different concentrations and intensities, confirms the third-order response. The optical limiting property of the dye was also studied. The overall results confirms the titled dye can be a suitable material for nonlinear optical applications.

A Comprehensive Topological Analysis on a New Bromine-Chalcone with Potential Nonlinear Optical Properties.

The application of organic crystals on nonlinear optical (NLO) materials has been increasing in recent years, and compounds like chalcones are interesting due to their significant third-order nonlinear properties. Hereof, we describe the synthesis, molecular structure, supramolecular arrangement, and theoretical calculations for a bromine-chalcone 3-(4-bromophenyl)-1-[3-(2-oxo-2-phenylethoxy)phenyl]-propenone (BC), which crystallized into noncentrosymmetric space group Pc. Also, a comprehensive topological analysis performed by QTAIM highlights the observed halogen bonds on solid state. In addition, the thermal stability was studied in temperatures smaller than 800 °C showing BC crystal as potential optical devices at temperatures up to 250 °C. Finally, the NLO properties indicate a photonic application based on strong third-order nonlinear response.

Correlating structure with third-order optical nonlinearity of chalcogenide glasses within a germanium–sulfur binary system

In this work, a series of germanium–sulfur (GeS) chalcogenide glasses (ChGs) was prepared. The third-order optical nonlinear (TONL) properties of ChGs were measured using Z-scan technique at 800 nm. A rapid decrease of optical bandgap energy (Eopg) and rapid increase of nonlinear refractive index (n2) were observed at a mean coordination number (MCN) of 2.67, which is known as the second topological threshold. Raman spectra showed that the appearance of [Ge(Ge2S2)] tetrahedra in the glass network is responsible for the decrease of Eopg at the threshold MCN and the significant enhancement to the TONL properties of the GeS ChGs.

Investigation of optical limiting and third-order optical nonlinear properties of 2-Nitroaniline by Z-scan and f -scan techniques

The nonlinear optical properties of 2-Nitroaniline, which is known to be a superior nonlinear optical material, have been investigated. The optical properties, such as absorption coefficients, are analyzed with UV visible spectroscopy analyses. The third-order nonlinear optical properties of the sample are analyzed with Z-scan, Eclipse Z-scan and f -scan techniques. The nonlinear absorption coefficient, nonlinear refractive index and third-order susceptibility are examined using open aperture and closed aperture Z-scan methods. The nanoscale sensitive variations in the nonlinear optical properties are observed with the Eclipse Z-scan method. The third-order optical nonlinearities occurring in the nanoscale range are also analyzed using the f -scan method and compared with the results obtained from the Z-scan measurement. The optical limiting characteristics of the sample have also been examined for its low-power optical limiting applications.

Tailoring mode splitting and degeneracy in silicon triply resonant nanobeam cavities

We investigate the use of coupled silicon nanobeam cavities for achieving multiple resonances as a photonic dedicated platform for nonlinear signal processing and sensing. The transmission spectra of the triple-coupled cavities were measured, and high quality factors, up to about 80,000, have been experimentally reported. By precisely varying the positions of three cavities vertically and horizontally, evolutions of the supermodes were fully mapped, in good agreement with the simulation designs. Some specific and interesting properties such as the dark state of the system, leading to unique transmission spectra, have been clearly observed. Based on a geometrical control of the structure, the three resonances can be tuning independently, and degeneracy modes emerge in some configurations when the distance parameters are properly chosen. This triple-resonant device is expected to enable the adjustment of third-order nonlinear properties in silicon photonics, and it is also a candidate for sensing or reconfigurable and programmable photonics.

The third-order nonlinear optical properties of gold nanoparticles-methylene blue conjugation

Third-order nonlinear properties of a thiazine dye (methylene blue (MB)) and a plasmonic nanoparticle (gold nanoparticles (GNPs)) have been studied by Z-scan method with a 50 mW continues wave (CW) diode pumped solid state laser (DPSSL) operating at 532 nm. The nonlinear parameters (nonlinear refractive (NLR) index (n2) and nonlinear absorption (NLA) coefficient (β)) are determined. The mechanism of the observed NLA and nonlinear refraction is attributed respectively to reverse saturable absorption (RSA) and thermal nonlinear effects. The magnitude of the measured NLR index (n2) and NLA coefficient (β) are founded to be the order of 10−8 cm2/W and 10−4 cm/W respectively. The effect of MB and GNPs on each other has been studied. Z-scan experiments for GNPs-MB conjugation shows noticeable increase in nonlinear parameters.

Third-order optical nonlinearities of 1,5-Diaminoanthraquinone for optical limiting application

Third-order nonlinear optical properties of 1,5-Diaminoanthraquinone have been studied. The vibrational and optical properties of the compound were analysed experimentally by FT-IR, FT-Raman and UV–visible spectroscopic characterization combined with theoretical DFT method. Intermolecular interactions in the compound have been confirmed by Hirshfeld surface and its associated two-dimensional fingerprint plots. First- and second-order hyperpolarizabilities of the title compound were computed theoretically by B3LYP and CAM-B3LYP hybrid functionals at DFT level. The third-order nonlinear optical parameters such as nonlinear refractive index (n2), nonlinear absorption coefficient (β), real, imaginary parts of third-order susceptibility (χ(3)) and second-order hyperpolarizability (γ) of the title compound were measured experimentally by open and closed aperture Z-scan technique. The Z-scan results confirm the reverse saturable absorption behaviour and positive nonlinear refractive property of the dye. These attractive third-order nonlinear properties suggest the title compound can be a good candidate for optoelectronic and photonic applications, furthermore the optical limiting property and laser damage threshold studies recommend the compound can be a promising material for laser-assisted applications.