Order Nonlinear Optical Response Research Articles

Correlation of quantum well periods on the 3rd order nonlinear optical responses of InGaN/GaN heterostructures

Semiconductor multi quantum well (MQW) design allows for the compression of electron-interaction dimensions, offering advantages for various applications, particularly in nonlinear optics. Despite the potential improvements in nonlinear optical responses, the influence of quantum well periods remains unexplored. In this study, we report the correlation of quantum well periods on the 3rd order nonlinear optical properties in In0.15 Ga0.85 N/GaN MQW using z-scan technique under femtosecond and continous wave laser regime. In0.15 Ga0.85 N well/GaN barrier with x1, x5, x10, x15 periods were grown by MOCVD technique. Good structural quality of grown MQWs were confirmed via HRTEM imaging, EDS, AFM and XRD. Absorption coefficient from UV-Vis coupled with PL emission spectrum shows systematic response of optical linear properties which provide an insight on the overall band gap structure. Positive nonlinear refraction, n2 and nonlinear absoprtion, β trends is observed under femtosecond an CW laser albeit differences of one order magnitude in χ3 value. The increase in χ3 value is shown to be monotonous with the increasing number of quantum well suggesting that compounding effect took place. This findings indicate the possibility of manipulating and tuning nonlinear reponses of MQW structures leading to improvement in semiconductor design in various areas such as optoelectronics, photonics, solar cell research, as well as quantum information processing.

Benzo‐bisimidazole based nanosheets having porphyrin like internal core with high second order nonlinear optical response: A theoretical perspective

AbstractThe 2D network having porphyrin like internal core are well established in literature due to their remarkable molecular tunability, photophysical and optoelectronics properties. Therefore, in the quest to attain the high performance nonlinear optical (NLO) response we have designed single Benzo‐bisimidazole (BIZ) unit which has porphyrin like motif and expanded it strategically in such a way that it forms cage and further it convert into 2D nanosheet. Density functional theory (DFT), sum‐over‐state models and time dependent‐DFT (TD‐DFT) simulation were performed for geometric and electronic properties calculation. Expanding the BIZ plays a pivotal role in enhancement of the first static hyperpolarizability (βtot) from 205.65 to 13754.59 au. Further, alkali metals substitution leads to gigantic enhancement of βtot value from 2200.17 to 636673.60 au which is enormously higher than that of recently reported porphyrin derivative (47950 au). Calculated results revealed that the gap between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) become narrow down from 6.28 eV (1) to 1.70 eV (6). It is to note that the designed molecules exhibit red shift of absorption. Further, density of states (DOS), and transition density matrix (TDM) analysis have also performed to explore the charge transfer and structure property relationship.

Heterostructure nanocluster MOF-derived Ag-CuO: An emerging material for harmonic soliton pulses generation

In recent years, metal-organic framework (MOF) and their derivatives have attracted many researchers due to excellent characteristics, such as good stability, high capacity, and a modest third order nonlinear optical response. Compared with conventional optical materials, MOF-oxide are easier to benefit photonic research. However, for nonlinear optics and ultrafast photonics, research on MOFs-Transition metal oxide is still in its infancy. In this work, MOF-derived Ag-CuO was prepared by hydrothermal method and applied in passively mode-locked fiber laser. Experimental results show that MOF-derived Ag-CuO possesses excellent optical absorption, functioning as a saturable absorber (SA). The laser based on MOF-derived Ag-CuO SA realizes three different mode-locking states, including traditional soliton with the pulse width of 1.04 ps, 32nd order harmonic soliton molecule, and soliton rain pulse, with the signal-to-noise ratio (SNR) of 73 dB. This work lays the foundation of its application in ultrashort photonics and optical communication, broadening the future of MOF-derived Ag-CuO.

Third order nonlinear optical, dielectric, photoluminescence and thermal analysis of Gd3+ doped glycine copper chloride (GCC) crystals

In the present investigations, metal-organic third order nonlinear optical (NLO) crystals of glycine copper chloride (GCC) and gadolinium (Gd) doped GCC with molecular formula (C2H5NO2CuCl2)1−x [Gd(NO3)3]x, where [x = 0.05, 0.10, 0.20] have been successfully grown. The growth of these semi-organic crystal compositions has been achieved at room temperature by slow solvent evaporation technique. The crystals exhibit excellent properties which get confirmed by various characterization studies like single crystal X – ray diffraction (SCXRD), powder X – ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV – Vis), photoluminescence (PL) spectroscopy, thermal analysis, electrical and nonlinear optical studies. SCXRD confirms that the grown crystal crystallizes in tetragonal crystal system having space group P42/mnm. The PXRD shows the appearance of sharp and strong peaks which refers to the good crystallinity and phase purity of the grown crystals. FTIR was recorded in order to identify various expected functional group. Linear optical behaviour using UV – Vis confirms the compositions to have good optical transmission in the entire visible region and lower cutoff wavelength ranging between 225 and 244 nm which is essential parameter for developing optoelectronic devices. The band gap value comes out to be in the range of 5.43 – 5.53 eV. The grown crystals possess excellent thermal stability. Results of dielectric studies conducted as a function of temperature divulged the electrical properties of crystals. Third – order nonlinear optical (TONLO) response have been observed using Z – scan setup. The calculated TONLO parameters n2, β, and χ(3) shows large value suggests that grown compositions can be used in practical non linear optical device applications.

Liquid-assisted mechanochemical synthesis, crystallographic, Hirshfeld surface and theoretical study for Nonlinear Optical (NLO) properties of novel copper complexes: Bis(2,9-dimethyl-1,10-phenanthroline)-copper perchlorate and bromidobis(1,10-phenanthroline)-copper

The two novel Cu (I) complexes, [Cu(dmp)2]ClO4 with 2,9-dimethylphenanthroline (dmp) and [Cu(phen)2Br] with 1,10-phenanthroline (phen) were synthesized by liquid assisted grinding (LAG) method followed by heating. Complexes were characterized by using SC-XRD, FT-IR and UV-Visible spectroscopic techniques. The complex (1) [Cu(dmp)2]ClO4 crystallized in the Orthorhombic with the space group P 21 21 21, a = 11.9229(2) Å, b = 12.4823(3) Å, c = 18.2499(3) Å and Complex (2) [Cu(phen)2Br] crystallized in the Monoclinic with the space group C2/c, a = 23.247(5) Å, b = 30.731 (6) Å, c = 7.5317(15) Å and β = 97.677(6)o. The FMOs study based on DFT showed the complex (2) has high value of chemical softness and more easily polarized compare to complex (1). The HOMO-LUMO energy gap in complex (2) is small compared to complex (1) due to which there is easier intramolecular charge transfer (ICT) in complex (2) which support the higher third order NLO (γ) response of the complex (2). The statistical calculations for Pearson correlation coefficient (r) and the P values showed that the selected level of theory is appropriate for the theoretical calculations of the complexes. Theoretical calculation showed that both the complexes have higher third order NLO response compared to prototypical urea.

Synthesis of ZnO nanostructures and its effect on linear-nonlinear optical properties

Zinc oxide (ZnO) nanostructures with nanoparticle morphology have been synthesized at ambient pressure and different temperatures using [OMIM]Br ionic liquid as solvent by ionothermal method. The products were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Z-scan technique. The average crystallite size of ZnO was between 15-23 nm. The band gaps of products are 3.19, 3.25, and 3.32 at 65, 90, and 120 oC, respectively. The Z-scan technique was proposed to detect the nonlinear optical (NLO) properties at 532 nm wavelength. Temperature effect on third order NLO responses of ZnO nanostructures is studied. The results show that higher annealing temperature in ionic liquid produced ZnO nanoparticles with decreased crystalline and enlarged band gap. Also, this process leads to produce ZnO nanoparticles with increasing NLO responses by altering vacancy distribution.

Annealing in ionic liquid for synthesis of ZnO nanostructures and its effect on linear-nonlinear optical properties

Zinc oxide (ZnO) nanostructures with nanoparticle morphology have been synthesized at ambient pressure and different temperatures using [OMIM]Br ionic liquid as solvent and template by ionothermal method. The products were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), diffuse reflectance spectra (DRS), and Z-scan technique. The average crystallite size of ZnO was between 12 and 14 nm. The band gaps of products are 3.19, 3.25, and 3.32 at 65, 90, and 120 ֯C, respectively. The Z-scan technique was proposed to detect the nonlinear optical (NLO) properties at 532 nm wavelength. Temperature effect on the third order NLO responses of ZnO nanostructures was studied. The results show that higher annealing temperature in the ionic liquid produced ZnO nanoparticles with an increased crystalline structure and enlarged band gap. Also, this process leads to produce ZnO nanoparticles with increasing NLO responses by altering oxygen vacancy distribution. Furthermore, prepared ZnO samples in higher temperatures and longer exposure time in [OMIM]Br ionic liquid are more effective than Cu-doped ZnO in nonlinear coefficient response.

Molecular modeling of mordant black dye for future applications as visible light harvesting materials with anchors: design and excited state dynamics

In this study, new visible light harvesting dyes (MBR1-MBR5) have been designed as efficient materials with silyl based anchoring abilities on semiconducting units for future dye-solar cells applications. Their unique molecular structures of novel D-π-ASemiconductor typewere evaluated thoroughly by density functional theory (DFT) calculations. To enhance the optical performance in visible region, a novel dye structure (MBR) was derived from the chemical structure of mordant black (MB) dye with electron acceptor semiconducting units (MBR1-MBR5). The Coulomb-attenuating Becke, 3-parameter, Lee-Yang-Parr (CAM-B3LYP) functional, which had a hybrid and long-range correlation with 6-31G + (d,p), generated a [Formula: see text] (683nm) that was very comparable to its experimental value (672nm). The energies of highest occupied molecular orbitals (HOMO), lowest unoccupied molecular orbitals (LUMO), and their HOMO-LUMO energy gaps (HLG) were calculated. Their ionization potentials (IP) varied from 5.616 to 8.320eV, demonstrating their good electron donating trend. The [Formula: see text] values of dyes displayed a significant red shift from MBR (682nm) value with range 565-807nm except MBR1 which was slightly blue shifted. The dye MBR4, which had the smallest HLG (0.23eV) had the greatest second order nonlinear optical (NLO) response of 144,234 Debye-Angstrom-1. The DFT calculated results provided insight into the creation of new silyl anchoring groups for future DSSCs material designs with increased stability and effectiveness. The goal of the current study is to forecast the development of novel NLO materials with a D-π-ASemiconductor design that use semiconductors as anchoring groups to adhere to a surface.

Third-order nonlinear optical responses of bis(15-crown-5)-stilbenes binding to one- or two-alkali metal cation (Li+, Na+ and K+)

Bis(15-crown-5)-stilbenes containing crown ether parts have been widely used in a variety of chemical applications, such as cation detectors, because of their ability to selectively bind to alkali metal cations, Bis(15-crown-5)-stilbenes and its derivatives with complexation of one- or two-alkali metal cation (Li+, Na+ and K+) have been theoretically investigated by quantum chemistry methods. The coordination of alkali cations results in partial shrinkage of crown ethers, which directly affected natural distribution analysis charges and molecular orbital energy levels. The number of alkali metal ions has significant effects on absorption spectra and mean second hyperpolarizability. When one alkali metal ion was added to the anticonformer of bis(15-crown-5)-stilbene, the absorption spectra were obviously redshifted and the mean second hyperpolarizability values were slightly increased; while two alkali metal ions were added to bis(15-crown-5)-stilbene, the absorption spectra were obviously blue shifted and the mean second hyperpolarizability values decreased. On the other hand, as the radius of the alkali ions increased, the mean second hyperpolarizability values of the compounds increased gradually. It is indicated that the mean second hyperpolarizability value is sensitive to the number and radius of the alkali metal cations, thus the third order nonlinear optical response can be used as a signal to detect the number and type of alkali metal ions.

Electrochemically-Switched 2nd Order Non-Linear Optical Response in an Arylimido-Polyoxometalate with High Contrast and Cyclability.

Electrochemically switched 2nd order non-linear optical responses have been demonstrated for the first time in polyoxometalates (POMs), with an arylimido-derivative showing a leading combination of high on/off contrast (94 %), high visible transparency, and cyclability. Spectro-electrochemical and TD-DFT studies indicate that the switch-off results from weakened charge transfer (CT) character of the electronic transitions in the reduced state. This represents the first study of an imido-POM reduced state, and demonstrates the potential of POM hybrids as electrochemically activated molecular switches.

Optimizing laser induced nonlinear optical, dielectric and microscopic traits of copper sulfate crystal by glycine for photonic device applications

• First comparative article on pure and glycine doped copper sulfate crystal has been reported. • Glycine enhanced optical transmittance of copper sulfate by 8% within 300-698 nm. • Glycine optimized third order nonlinear optical properties of copper sulfate crystal. • Glycine enhanced the laser induced damage threshold energy of copper sulfate by 55 mJ. • Glycine significantly reduced the dielectrics of copper sulfate crystal. Novel investigation reports mono crystal growth of pristine and glycine (C 2 H 5 NO 2 ) doped copper sulfate (CS) by slow solvent evaporation method. The structural analysis has been performed by single crystal X-ray diffraction technique. The presence of various chemical components has been qualitatively established by energy dispersive spectroscopy. The UV-visible spectroscopy has been employed within 200-1000 nm to evaluate the rise in optical transmittance of CS crystal due to glycine. Influence of glycine on third order nonlinear optical response of CS crystal has been examined at 632.8 nm by means of He-Ne laser assisted Z-scan technique. The laser induced surface damage tolerance limit of pure and glycine doped CS crystal has been comparatively investigated at 1064 nm. The impact of glycine and temperature on dielectric traits of CS crystal has been investigated by means of dielectric studies. A comparative etching analysis has been done to investigate surface attributes of pure and glycine doped CS crystal.

Nonlinear optical properties of lithium niobate crystals doped with alkaline earth and rare earth elements

Nonlinear optical properties of lithium niobate crystals doped with alkaline-earth (Zn2+) and rare-earth (Er3+) elements were quantitatively studied from the chemical bond viewpoint of crystal. The different influences of Zn and Er dopants on the dielectric response of LiNbO3 were compared. The value of nonlinear optical second-harmonic generation coefficients was determined mainly by the Li–O bonds both in LiNbO3:Zn and LiNbO3:Er crystals. We observed sharp changes in the second order nonlinear optical response of Zn-doped LiNbO3 single crystals at 1064 nm with increasing Zn concentration in the crystal. The calculated values of the nonlinear optical coefficients for the LiNbO3:Zn crystals exceed those for the LiNbO3:Er crystals. The LiNbO3:Zn crystal with dopant concentration 5.48 mol.% is the most suitable crystal for the second-harmonic conversion.

The effect of intramolecular and intermolecular charge transfers on the third order nonlinear optical properties of the self−assemble chromophores

Self-assembled chromophores were widely used in nonlinear optical devices due to their unique charge transfer properties. The structures, intermolecular interactions, absorption spectra, charge transfer (CT) and third order nonlinear optical (NLO) responses (γ) of monomers, dimers and trimers based on N,N′-butyl-3,4,9,10-perylenediimide (PDIB) have been studied using density functional theory. It is found that with the addition of phenyl substituents, the Egap values between HOMO and LUMO of monomers as well as dimers and trimers decreases gradually, their main absorption peaks of the absorption spectra were redshifted, and intramolecular CT was more pronounced, thus their γ values increased gradually. Moreover, the intermolecular interaction energies (Eint) of dimers increases with the addition of phenyl substituents, indicating that the enhancement of Eint values increases the degree of intermolecular electron coupling and enhances intermolecular CT. On the other hand, in order to explore the effect of increasing number of layers on the optical properties of dimers and trimers, we divide the γ values by the number of layers (n = 1, 2 and 3). It is found that the average γ/n values decreases as n increases, which was due to that the CT in homomolecular self-assembly was non-directional, even isotropic and cancelling. We hope that this work will lead to the careful design of self-assembled NLO materials.

High performance nonlinear optical materials with simple aromatic hydrocarbons

Design of novel functional materials with high-performance and high stability are of great importance in the field of nonlinear optics. In the present work, a new protocol is proposed for designing optical and nonlinear optical (NLO) functional material through proper interplay of functional moieties (in this work, benzene, naphthalene and azulene) by geometric arrangement within the classical D-π-A paradigm. The π-conjugation across the fused aromatic benzene, naphthalene and azulene, and the electronic structure retention of those functional moieties lead to the redistribution of π-electron in azulene-based polar carbon chains and bring about large second order NLO responses. The charge transfer based electron transition at low energy field has a dominant contribution to the large static first hyperpolarizability (<β0>). The strong second order NLO responses under external fields, e.g., sum frequency generation and difference frequency generation, render these azulene-based molecules promising candidates for optoelectronic functional materials with high-performance in visible and near-infrared regions. The protocol of designing optical and nonlinear optical materials through manipulating the interactions among functional moieties is extendable to designing other optico-electronic functional materials.

Shedding light on the second order nonlinear optical responses of commercially available acidic azo dyes for laser applications

Nonlinear optics is a field of immense scientific interest and research owing to its extensive applications in photonics and optoelectronics. NLO materials are crucial components of optical fibers, optical computing, data processing devices, optical sensors, optical modulators, high density optical storage devices, and ultra-fast optical switches. Herein, five commercially available azo dyes, Acid Orange 5, Acid Orange 61, Direct Red 111, Food Yellow 6 and Metanil Yellow are theoretically investigated for their electronic and nonlinear optical properties using density functional theory (DFT) methods. Each azo dye exhibits one alkaline and two acidic forms therefore, all three forms of these azo dyes are considered for calculations. FMO analysis shows reduced HOMO-LUMO energy gaps (Eg) for acidic forms as compared to alkaline forms. The lowest HOMO-LUMO energy gap of 2.54 eV is observed for AO61 AC I acidic form. Furthermore, the effect of protonation of the dyes on nonlinear optical (NLO) responses are thoroughly investigated. The results at CAM-B3LYP/6-311+G(d) show that the protonation brings significant increase in nonlinear optical response. The highest first hyperpolarizability is observed for DR111 AC II (βo = 2.6 × 104au). The lowest hyperpolarizability calculated for Acid Orange 61 is even greater than that of the prototype, p-nitroaniline (1.2 × 103au). TD-DFT calculations are also carried out to find first hyperpolarizabilities βo by using two-level-model. The variations in dipole moments and excitation energies are the decisive factors for the increased first hyperpolarizabilities. In order to find the practical applications of the dyes in the field of nonlinear optics, dynamic hyperpolarizabilities for hyper-Rayleigh scattering (HRS), second harmonic generation (SHG) and electro-optical Pockel's effect (EOPE) are computed at a varying range of incident wavelengths. The results are found to be quite supportive for application of the studied azo dyes in second harmonic generation phenomenon.

Visible-light-driven photocatalytic activation of peroxymonosulfate by K+-reformed polymeric carbon nitride for effective sulfamethoxazole decomposition

The SO4•– radical based advanced oxidation process (SR-AOP) is the effective remediation strategy for addressing the concern of severe pollution risk caused by recalcitrant pollutants. In this study, we report the visible-light-driven photocatalytic activation (VL-PCA) of PMS by using K+-induced structure remodeling high crystallinity of (KPCN). The degradation of sulfamethoxazole (SMX) by KPCN+PMS+VL system (the corresponding kinetic constant is 0.1452 min–1) was enhanced remarkably compared with PCN+PMS+VL system (0.0263 min–1). •O2–, 1O2, •OH and SO4•– radicals were the dominant reactive species for the enhanced decomposition of SMX, evidently demonstrated by reactive species scavenger and electron paramagnetic resonance (EPR) experiments. The KPCN crystalline semiconductors maintain the properties of long-range atomic order configuration and nonlinear optical (NLO) response of pristine PCN. The unique NLO effects of KPCN enable it to produce more photogenerated carriers and minimize the electron-hole pair recombination, which exhibit superior VL-PCA performance of PMS toward SMX degradation. This study gives a proof-in-concept demonstration of the increased activity of the C3N4-based PMS photocatalytic-activator by regulating the disordered structure and phase defects of PCN, shedding light on the development of highly efficient VL-PCA catalysts based on carbon nitride.

Tunable Lifetime and Nonlinearity in Two Dimensional Materials Plasmonic-Photonic Absorber.

We investigate a framework of local field, quality factor and lifetime for tunable graphene nanoribbon plasmonic-photonic absorbers and study the second order and third order nonlinear optical response of surface plasmons. The energy exchange of plasmonic-photonic absorber occurs in two main ways: one way is the decay process of intrinsic loss for each resonant mode and another is the decay process of energy loss between graphene surface plasmon (GSP) mode and the external light field. The quality factor and lifetime of the plasmonic-photonic absorber can be obtained with using the coupled mode theory (CMT) and finite difference time domain (FDTD) method, which are effectively tunable with changing Fermi energy, carrier mobility and superstrate refractive index. The evolutions of total energy and lifetime of GSP are also shown, which are helpful for the study of micro processes in a two-dimensional material plasmonic-photonic absorber. The strongly localized fundamental field induces a desired increase of second harmonic (SH) wave and third harmonic (TH) wave. The manipulation of the quality factor and lifetime of the GSP makes graphene an excellent platform for tunable two-dimensional material plasmonic-photonic devices to realize the active control of the photoelectric/photothermal energy conversion process and higher harmonic generation.

Spin engineering of triangulenes and application for nano nonlinear optical materials design.

The recently synthesized triangulenes with non-bonding edge states could have broad potential applications in magnetics, spintronics and electro-optics if they have appropriate electronic structure modulation. In the present work, strategies based on molecular orbital theory through heteroatom doping are proposed to redistribute, reduce or eliminate the spin of triangulenes for novel functional materials design, and the role of B, N, NBN, and BNB in such intended electronic structure manipulation is scrutinized. π-Extended triangulenes with tunable electronic properties could be potential nonlinear optical (NLO) materials with appropriate inhibition of their polyradical nature. The elimination of spin is achieved by B, N, NBN, and BNB doping with the intended geometric arrangement for enhanced polarity. Intended doping of BNB results in an optimal structure with large static first hyperpolarizability (〈β0〉) as well as strong Hyper-Rayleigh scattering (HRS) βHRS(-2ω; ω, ω) (ω = 1064.0 nm), TG7-BNB-ba with a large 〈β0〉 (18.85 × 10-30 esu per heavy atom) and βHRS (1.15 × 10-28 esu per heavy atom) much larger than that of a synthesized triangular molecule (1.12 × 10-30 esu of 〈β0〉 per heavy atom and 5.04 × 10-30 esu of βHRS per heavy atom). The strong second order NLO responses in the near-infrared and visible regions, particularly the strong sum frequency generation, make these B or (and) N doped triangulenes promising candidates for the fabrication of novel carbon-based optoelectronic devices and micro-NLO devices.

Theoretical assessment of the influences of aromatic bridges on molecular second order nonlinear optical responses of Donor-Bridge-Acceptor types of molecular organic chromophores

Push-pull types Donor-Bridge-Acceptor (D-B-A) organic molecules have been reported as efficient functional materials for various technological applications. Often their interesting properties were reported to be directly linked to their nature of intramolecular charge transfers (ICT). Bridge that connects the D with A, plays the vital role in the ICT processes. A recent report of comparative experimental and computational nonlinear optical (NLO) study, shows many interesting behaviours exhibited by aromatic (diazine, thiophene and benzene rings) bridges. Many earlier studies also exist, where effects of one or more of aromatic bridges were investigated for NLO applications. But no systematic comparative study with well-known aromatic bridges at one place exist in literature. Inspired by those earlier works, this computational work reports the influences of a set of mono-aromatic ring bridges on NLO properties for a set of D-B-A types of organic molecules. This work can be expected to serve as a reference for many researchers working in the search of new and efficient functional materials.

The effect of nitrogen-doped carbon nano-onions on the third order nonlinear optical responses of CoWO4-MnO2 nanocomposites

CoWO4, CoWO4-MnO2, and CoWO4-MnO2-NCNO nanostructures were prepared via precipitation method followed by calcination at 450 °C. The nitrogen-doped carbon nano-onions (NCNOs) were synthesized by annealing the ultra-dispersed aminated-nanodiamond solution under He gas at 1150 °C followed by calcination at 400 °C. The morphological, structural, and optoelectronic responses of the samples were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Z-scan methods. The order of the nonlinear absorption (NLA) and nonlinear refraction (NLR) of samples are 10−3 (cm/W) and 10−8 (cm2/W), respectively. In different incident intensity of laser, all synthesized samples showed positive and negative sign of NLA and NLR indices, respectively. The NLA coefficient originates from two photon absorption effect and NLR indices indicate the self-defocusing effect. The lowest nonlinear optical response belonged to CoWO4 nanoparticles. CoWO4-MnO2-NCNO nanocomposite showed the higher nonlinear optical responses than CoWO4 and CoWO4-MnO2 nanocomposites. The large ratio of the surface area of NCNO and oxygen reduction activity of NCNO due to high incident intensity are the main reasons for increasing nonlinearity. The nonlinearity results are promising candidate for using in optical and photonic devices.