Third-order Nonlinear Optical Studies Research Articles

Polyhedral {Ag12} and {Ag16} Clusters: Synthesis, Structural Characterization and Third-Order Nonlinear Optical Properties.

Two polyhedral silver-thiolate clusters, [S@Ag16(Tab)10(MeCN)8](PF6)14 (Ag16) and [Ag12(Tab)6(DMF)12](PF6)12 (Ag12), were synthesized by using electroneutral Tab species as protective ligands (Tab = 4-(trimethylammonio)benzenethiolate, DMF = N,N-dimethylformamide, MeCN = acetonitrile). Ag16 has a decahedral shape composed of eight pentagon {Ag5} units and two square {Ag4} units. The structure of Ag12 is a cuboctahedron, a classical Archimedean structure composed of six triangular faces and eight square faces. The former configuration is discovered in silver-thiolate cluster for the first time, possibly benefited from the more flexible coordination between the Tab ligand and Ag+ facilitated by the electropositive -N(CH3)3 substituent group. Third-order nonlinear optical studies show that both clusters in DMF exhibit reverse saturate absorption response under the irradiation of 532 nm laser.

Investigations on structural, dielectric, and third-order nonlinear optical studies of Ni0.5Zn0.5Fe2O4 nanoparticles by microwave combustion method with different fuels (glycine, urea and citric acid)

In this article, Ni0.5Zn0.5Fe2O4 nanoparticles (NPs) were synthesized via microwave-assisted combustion method. XRD investigation indicates the cubic spinel structure. At ambient temperature, the dielectric constant and loss were determined by modulating the applied frequency (50 Hz to 200 kHz). The calculated third-order NLO susceptibility (χ(3)) was found for glycine (2.385 × 10-6esu), urea (0.9696 × 10-6esu) and citric acid (2.755 × 10-6esu). However, this work reveals that synthesized NPs have high convenience for optoelectronic, optical switching, and limiting applications.

Theoretical design, synthesis, third-order nonlinear optical properties and DNA binding studies of benzothiadiazole based conjugated polymer

Benzothiadiazole based copolymer P(BTZ-BT) was theoretically designed by density functional theory methods employing B3LYP/6–31 G (d,p) and HSE06/6–31 G (d,p) basis sets. A low band gap of 1.31 eV was observed for the copolymer by HSE06/6–31 G (d,p) basis set. TG analysis of the polymer showed high thermal stability at 500 °C. Experimentally observed band gap for the copolymer was 1.66 eV by cyclic voltammetry. Fluorescence lifetime of the polymer P(BTZ-BT) was studied and it exhibited an average lifetime of 2.59 ns. The copolymer exhibited positive solvatochromism with a Stoke's shift value ranging from 3082 cm−1 to 4569 cm−1. Open-aperture Z-scan traces of the copolymer in DMSO at 91µJ, 165 µJ, 285 µJ and 450 µJ showed positive NLO absorption coefficient β in the range of 10−10m/W and exhibited optical threshold value of 0.03 GW/cm2, 0.05 GW/cm2 and 0.12 GW/cm2 respectively. No linear transmission was observed at 450 µJ for the copolymer during the study of optical limiting property. DNA binding studies of the copolymer with double stranded calfthymus DNA was carried out. Fluorescence observed for the copolymer was quenched by 85% on interaction with the ct-DNA and gradual decrease was observed in the lifetime of the copolymer from 2.59 ns to 1.8 ns.

Comment on crystal growth, spectral, structural, linear, and third-order nonlinear optical and mechanical studies of a novel semi-organic single-crystal l-methionine barium nitrate (LMBN) for optical limiting applications

Comment on crystal growth, spectral, structural, linear, and third-order nonlinear optical and mechanical studies of a novel semi-organic single-crystal l-methionine barium nitrate (LMBN) for optical limiting applications

Positron lifetime and third-order nonlinear optical studies of P(St-co-MMA)/NiO polymer nanocomposites

Polymer nanocomposites of Poly(styrene-co-methylmethacrylate) (P(St-co-MMA))/Nickel oxide (NiO) with different NiO nanoparticles wt% (0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) are prepared by solution casting technique. The UV–Vis and XRD results revealed decreased direct energy band gap, increased Urbach energy and decreased crystallinity with the increased NiO nanoparticles wt%. The SEM results show the agglomeration of nanoparticles for higher concentrations of NiO nanoparticles loading. The Z - scan studies show the increased nonlinear optical (NLO) parameters viz., nonlinear absorption coefficient (β), nonlinear refractive index (n2) and nonlinear susceptibility (χeff(3)) with increased NiO nanoparticles wt%. The free volume parameters viz., free volume (Vf) and fractional free volume (Fv) show increasing and decreasing trends with the NiO nanoparticles concentration respectively. The effect of free volume parameters on nonlinear optical parameters such as β,n2 and χeff(3) is brought out. The increased β,n2 and χeff(3) is due to the increased polarization by the NiO nanoparticles in P(St-co-MMA) polymer matrix. The decreased fractional free volume (Fv) with the increased NiO (wt%) indicates the increased packing density of polymeric chains of P(St-co-MMA) polymer matrix. The increased NLO parameters are attributed to the increased polarizability and packing density of polarizable groups in the P(St-co-MMA) polymer matrix.

Ethyl acetoacetate and acetylacetone appended hexabromo porphyrins: synthesis, spectral, electrochemical, and femtosecond third-order nonlinear optical studies.

Asymmetrically substituted porphyrins possessing ethyl acetoacetate or acetylacetone (EAA or acac) with six bromine atoms at β-positions were synthesized and then characterized by various spectroscopic techniques, such as UV-Vis, fluorescence and NMR, and also by CV, DFT, MALDI-TOF-MS and elemental analysis. The mechanistic pathway followed the nucleophilic substitution reaction (nucleophile: EAA and acac) with MTPP(NO2)Br6 (M = 2H, Cu(II), and Ni(II)), and the resultant β-heptasubstituted porphyrins exhibited keto-enol tautomerism, as supported by 1H NMR spectroscopy. The six bulky bromo and EAA/acac groups made the macrocyclic ring highly electron deficient and nonplanar such that the quantum yield and fluorescence intensity for H2TPP[EAA]Br6 and H2TPP[acac]Br6 were severely reduced in contrast to those values for H2TPP. The poor electron density and nonplanarity over the porphyrin ring shifted the first oxidation potential from 11 to 521 mV anodically for MTPP[X]Br6 [M = 2H, Cu(II), and Ni(II); X = EAA or acac] as compared to corresponding MTPPs. Notably, density functional theory proved the nonplanarity of the synthesized porphyrins as Δ24 spans from ±0.546 to ± 0.559 Å while ΔCβ stretches from ±0.973 to ±1.162 Å. The third-order nonlinear optical measurements were performed using the femtosecond pulsed laser Z-scan technique at 800 nm and 1 kHz repetition rate to acquire insights into nonlinear absorption and nonlinear refraction of the porphyrins. The three-photon absorption coefficients (γ) are in the range of 2.2 × 10-23-2.8 × 10-23 cm3 W-2 and the nonlinear refractive index values were in the range of 3.7 × 10-16-5.1 × 10-16 cm2 W-1. The higher-order nonlinear absorption exhibited by porphyrins helps improve resolution at depth for various photonic and optoelectronic applications.

Crystal growth, structural, optical, photoluminescence, electrical and third-order nonlinear optical studies of pure and methylene blue dye-doped ammonium dihydrogen phosphate crystals

Crystal growth, structural, optical, photoluminescence, electrical and third-order nonlinear optical studies of pure and methylene blue dye-doped ammonium dihydrogen phosphate crystals

Third-order nonlinear optical studies of Bis(4-methylbenzylammonium) tetrachloridocuprate metal-organic crystal with optical limiting behavior: Experimental and theoretical investigations

The metal-organic nonlinear optical (NLO) compound Bis(4-methylbenzylammonium) tetrachloridocuprate (4MBA) was synthesized and grown by the slow evaporation method. X-ray crystal analysis revealed the crystal structure and conformation. Density functional theory (DFT) at B3PW91/LanL2DZ basis set level was applied and computed the optimized geometry, electronic structure, vibrational spectra, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), and natural bonding orbitals (NBO). UV–Vis-NIR spectroscopic measurements revealed the optical transparency range from 310 to 1100 nm and excited-state properties. The thermal behavior and stability of the compound were analyzed using TGA/DTA, and the suitability of the optical material is weighed. The dielectric parameters and AC conductivity were investigated as a function of frequency and temperature. Second-harmonic generation (SHG) efficiency was measured using the Kurtz and Perry powder approach and found 4MBA to be 0.8 times the KDP. The nonlinear refractive index (n2), nonlinear optical absorption (β) and third-order nonlinear optical susceptibility (χ(3)) measured values are 1.548 × 10−9 cm2 W−1, 0.0538 × 10−4 cm W−1, and 6.049 × 10−8 esu respectively, and shows that the 4MBA molecule is a third-order nonlinear optical material. The optical limiting threshold value is determined as 7.632 × 103 W cm2 for 532 nm continuous-wave laser, representing that the 4MBA is a strong candidate for the optical limiting application. The static and dynamic nonlinear optical parameters were computed with three different functions including B3PW91, M06 and PBE0 using LanL2DZ basis set. The outcomes revealed that the 4MBA molecule under study might be a promising NLO material for frequency generators and optical limiters applications.

Investigation on growth, structural, DFT and third-order nonlinear optical studies of cyclohexylammonium 4-nitrobenzoate for optical limiting applications

Investigation on growth, structural, DFT and third-order nonlinear optical studies of cyclohexylammonium 4-nitrobenzoate for optical limiting applications

Hirshfeld surface analysis, enrichment ratio, energy frameworks and third-order nonlinear optical studies of a hydrazone derivative for optical limiting applications

Organic materials with good third-order nonlinear optical (NLO) properties are used in optoelectronics for protecting human eyes and sensors from high intensity laser light. In this regard, herein we report the synthesis, structural analysis, and third-order NLO properties of an organic molecule N'-[(E)-(4-fluorophenyl)methylidene]biphenyl-4-carbohydrazide (FMBC) containing hydrazone moiety. The formation of the synthesized molecule is confirmed by identifying the functional groups through FTIR spectral analysis. The material possesses good thermal stability before the melting point of 242.5∘C and transparent in the entire visible region of the EM spectrum. The photoluminescence study revealed the blue light-emitting property of FMBC. The crystal structure is stabilized by N-H···O, C-H···O, and C-H···F hydrogen bond interactions. The interconnects in the crystal packing were envisioned quantitatively using Hirshfeld surfaces (HS) by 2D fingerprint plots. The main contribution to the HS comes mainly from C-H, H-H, and O-H interconnects which cover about 80 % of the total HS surface. The enrichment ratios show that the favorable contacts accountable for the crystal packing are C···H, N···H, O···H, and F···H. The breakdown of the interaction energies obtained for various molecular pairs shows the nature and strength of the interactions. The calculation of 3D energy frameworks suggests that contacts formed in the structure are largely due to the dispersion force followed by the electrostatic potential. Third-order NLO coefficients were extracted under the continuous wave (CW) regime using z -scan technique. The material is an excellent optical limiter with a threshold value of 3.42 kJ/cm2. [Display omitted]

Structural, spectral, experimental, and theoretical investigations of (E)-4-fluoro-N′-(pyridin-2-ylmethylene)benzohydrazide monohydrate

The structural and nonlinear optical properties of the Schiff base material, (E)-4-fluoro-N′-(pyridin-2-ylmethylene)benzohydrazide monohydrate (FPMBH) were studied. The experimental investigations were performed using Fourier transform infrared (FTIR), ultraviolet (UV) and nuclear magnetic resonance (NMR) spectral techniques. The computational analyses were made by DFT method. A comparison between experimental and theoretical predictions was made and interpreted. The maximum absorption wavelength was found by both experimental and theoretical analyses. The Hirshfeld surface analysis was performed to understand the various molecular interactions. Highest occupied and lowest unoccupied molecular orbitals (HOMO–LUMO) analysis was performed for the title molecule to know about the possible charge transfer taking place within the molecule. Reactivity features were also determined by molecular electrostatic potential (MEP) analysis. The third-order nonlinear optical studies were done by z-scan experiment, and the results were discussed.

Ellipsometric and third-order nonlinear optical studies of pulsed laser deposited aluminium doped zinc oxide thin films

In the present work, an attempt is made to study the optical properties of aluminium doped zinc oxide (AZO) thin films fabricated by pulsed laser deposition (PLD) technique at different laser fluences. The non-polar ‘a-plane’ orientation of the AZO nanostructure is confirmed by x-ray diffraction technique. The linear optical parameters such as refractive index (n), extinction coefficient ( k ), and dielectric constants ( ε ) are studied by spectroscopic nulling ellipsometer. An increase in extinction coefficient with increase in wavelength is observed. This rare phenomenon is observed for the film prepared at highest laser fluence. The nonlinear optical properties of prepared AZO thin films are evaluated by employing an open aperture (OA) and a closed aperture (CA) Z-scan measurements at a continuous 532 nm wavelength laser source. The presence of reverse saturable absorption (RSA) is observed in all the films; which is attributed to the two-photon absorption mechanism. CA measurements revealed, a switching behaviour from self-de-focusing to a self-focusing mechanism. Third-order nonlinear optical susceptibility, χ ( 3 ) values of AZO films are found be in the order of 10 −6 e.s.u . Further, a-plane oriented AZO films showed optical limiting behaviour with promising optical threshold value (2.964 kJ/cm 2 ) .

Synthesis, characterization and investigation of linear and infra-red nonlinear optical properties of TiO2/ZnO core/shell nanospheres

Titanium dioxide nanoparticles have been synthesized by the chemical co-precipitation technique and then they have been coated with zinc oxide shell layers using a refluxing method to form TiO2/ZnO core/shell nanoheterojunctions. The physicochemical properties of as-synthesized core/shell nanoheterojunctions have been examined using X-ray diffraction (XRD), Fourier transfer infra-red spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). Photoluminescence (PL) emission spectroscopy has been carried out to analyze the linear optical characteristics at an excitation wavelength of 270 nm. A red shift towards longer wavelengths has been detected in NBE-related energies of TiO2/ZnO core/shell nanoheterojunctions compared to the sole TiO2 nanostructures. Third-order nonlinear optical studies have been performed by a single-beam Z-scan technique using a pulsed Nd-YVO4 laser system at a wavelength of 1064 nm. Third-order nonlinear refractive indices have been estimated as 10–12 m2/W. The sign of nonlinear refractive indices has been found to be negative, indicating self-defocusing behavior in the near infra-red region.

Third-order nonlinear optical studies of carbon nanotubes developed by floating catalyst technique

Abstract Carbon nanotubes were developed via floating catalyst technique using acetylene and ferrocene as carbon and catalyst precursors respectively at temperatures varying from 700 to 1150 °C. Structure and morphology were characterized via SEM, TEM and Raman spectroscopy. The dimensions and yield of grown CNT's were observed to be same in all temperatures. The crystalline perfection of CNT's was improved with an increase in temperature. It is observed that the temperature of the synthesis could affect the degree of nanotubes graphitization. Catalytic growth of CNT's was elucidated on the basis of the model of vapour-liquid-solid and the proposed model was supported by TEM. Growth rate of nanotubes rises at higher temperatures and graphite sheets builds with lower defect. Nonlinear optical and limiting characteristics were determined using ns pulses at 532 nm. CNT's display strong nonlinear absorption coefficient of 29.9 cm/GW. CNT's exhibiting excellent optical limiting with a limiting threshold of 3 J/cm 2.

Crystal growth, optical, thermal, laser damage threshold, photoconductivity and third-order nonlinear optical studies of KCl doped sulphamic acid single crystals

Good quality of pure and 1 mol% KCl doped sulphamic acid (SA) single crystal was grown by the solvent evaporation technique. The grown crystals belong to an orthorhombic structure. The peak present in the frequency region between 2870 and 3137 cm−1 is owing to NH3+ stretching vibration. The addition of dopant enhances the transmittance and mechanical strength of the SA crystal. The intense emission bands are obtained at 335 and 424 nm for pure and 337 and 468 nm for 1 mol% KCl doped SA crystal, respectively. The first decomposition point observed at 229 °C and 232 °C for pure and doped SA crystals, respectively. Laser damage threshold resistant of the crystals is 57, 89 and 132 mJ for KDP, pure and 1 mol% KCl doped SA crystals, respectively. The negative photoconductivity nature of title crystals was confirmed by photoconductivity studies. The third-order nonlinear optical (TONLO) susceptibility (χ3) of the pure and doped crystal is 5.004 × 10−10 esu and 7.848 × 10−10 esu, respectively. All the results show that the grown crystals have good transmittance, high LDT, mechanical, thermal and large susceptibility values. So, the title crystals are potential material for NLO applications.

Synthesis, characterization, third-order non-linear optical properties and DFT studies of novel SUBO bridged ball-type metallophthalocyanines.

Novel 4,4'-(((2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropane-2,1-diyl))bis(oxy)) (SUBO) bridged ball-type metallophthalocyanines were synthesized starting from 4,4'-(((2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropane-2,1-diyl))bis(oxy))diphthalonitrile with convenient metal salts in 2-N,N-dimethylaminoethanol. A new bisphthalonitrile compound was obtained from 2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropan-1-ol) and 4-nitrophthalonitrile in acetonitrile at reflux temperature in the presence of potassium carbonate as a catalyst. The structural characterization of the compounds was performed by elemental analysis, and infrared, ultraviolet-visible and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopic methods. Nonlinear absorptions of the phthalocyanine complexes were measured using the Z-scan technique with 7 ns pulse duration at a 532 nm wavelength. It is obvious that ball-type copperphthalocyanine has a high nonlinear absorption coeffıcient and imaginary component of the third-order susceptibility compared to other complexes. Therefore, ball-type copperphthalocyanine can be regarded as a very good candidate for optical limiting applications. Density functional theory was used for geometry optimizations and time-dependent density functional theory calculations of electronic transitions in order to compare with the experimental results. Molecular orbital and nonlinear optical analyses were also performed with density functional theory at the CAM-B3LYP/6-31G(d,p)/LANL2DZ level. The nonlinear optical analyses show that ball-type copperphthalocyanine has significantly better nonlinear optical properties in comparison to a common reference compound, urea.

Investigation on the growth, spectral, thermal, mechanical, electrical, laser damage threshold and third-order nonlinear optical studies of 4-acetylanilinium perchlorate (4AAPCl) semi-organic single crystal for optical limiting applications

Single crystal of 4-acetylanilinium perchlorate (4AAPCl) was obtained by slow evaporation technique. The grown 4AAPCl crystal characterized by single-crystal X-ray diffraction and powder XRD confirms that the crystal belongs to monoclinic system with the space group P21/c. The functional groups present in the crystal were analyzed using infrared, Raman and NMR spectral studies. The optical absorption properties of the grown material were ascertained by UV–visible NIR analysis. The crystal has an emission peak in the green region and higher laser damage threshold of 3.72 GW/cm2. The electrical properties of the grown crystal were measured from the frequency and temperature variations of the dielectric profile. TGA reveals that the 4AAPCl crystal was thermally stable up to 190 °C. Microhardness test showed that the grown crystal is soft in nature. The linear polarizability (α) and first-order hyperpolarizability (β) related to NLO activity of the crystal have been also calculated. The optical limiting action and third-order optical nonlinearity of the grown crystal were accurately measured using a standard Z-scan method.

Third-order nonlinear optical studies of two novel chalcone derivatives using Z-scan technique and DFT method

The present study reports the theoretical and experimental investigations of nonlinear optical properties of two novel chalcone derivatives namely (2E)-1-(Anthracen-9-yl)-3-(4-methoxyphenyl) prop-2-en-1-one (methoxy-ANC) and (2E)-1-(Anthracen-9-yl)-3-(4-ethoxyphenyl)prop-2-en-1-one (ethoxy-ANC). The theoretical calculations performed by density functional theory have been supported by the obtained experimental results. The FT-IR, FT-Raman and UV–visible absorption spectra were recorded and analysed. The optimized geometry, vibrational wavenumbers, HOMO-LUMO energy gap, Natural Bond Orbital (NBO) analysis, Natural Population Analysis (NPA) were computed by B3LYP level of theory with 6-311++G (d,p) basis set. The theoretical second-order hyperpolarizability were calculated using B3LYP and CAM-B3LYP hybrid functional. The third-order nonlinear optical properties, along with the optical limiting behaviour and laser damage threshold studies were carried out by Z-scan technique using Q-switched Nd: YAG laser with 5 ns pulses at 532 nm.

Investigations on physiochemical and third-order nonlinear optical studies on quinolinium based organic crystal

Newly identified organic single crystals of 8-hydroyquinolinium 2-chloro 4-nitrobenzoate (HQ2ClNB) were grown by the slow evaporation solution growth technique (SEST) using methanol as a solvent. It crystallizes in monoclinic crystal system with a space group of P21/c. Crystalline nature and phases were confirmed by powder X-ray diffraction (XRD). The existence of various functional groups in the molecule was identified using the Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) technique. Optical transmission window and lower cut-off wavelength of the HQ2ClNB crystal have been evaluated by UV–Visible–NIR studies. Dielectric and photoconductivity studies were recorded. Third-order nonlinear optical susceptibility [Formula: see text] of the crystals were evaluated by [Formula: see text]-scan studies.

Crystal growth, optical, physico-chemical and third-order nonlinear optical studies of morpholinium oxalate: a new organic single crystal for optical limiting application

A single crystal of morpholinium oxalate (MO) was grown by the technique of slow evaporation at ambient temperature utilizing water as a solvent. Single crystal XRD reveals the MO crystal belongs to the monoclinic system with a centrosymmetric space group of P21/n. Powder XRD study demonstrates the crystalline quality. HRXRD study illustrates the crystalline perfection of the crystal and it is the key necessity for device fabrication. The optical transmittance (55%), cut-off wavelength (λ = 330 nm) and band gap energy (Eg = 2.61 eV) were determined by optical studies. Laser-induced surface damage threshold (LDT) analysis appraises the aptness of grown crystal for device fabrications and also the surface roughness of the sample was determined. The thermal stability and decomposition of the crystal were studied by thermogravimetric (TG) analysis and it was found that the material was thermally stable up to 179 °C. The various thermodynamical parameters were determined from TG analysis. The dielectric constant ɛ’ and dielectric loss ɛ’’ divulges the electrical properties of MO crystal and the various electronic parameters were also calculated. The nonlinear optical (NLO) behavior and optical limiting property were analyzed from Z-scan technique. Microhardness measurement was executed to recognize the mechanical strength of the MO crystal and its hardness value is 1.65 kg/mm2.