Third-order Optical Properties Research Articles

A new mixed-ligand zinc(II) complex of 3-hydroxy and 4-chloro substituted pyridine-2-carboxylic acid: Synthesis, characterization, NLO properties and DFT calculation

Molecular engineering of metal-organic frameworks has recently attracted increasing attention due to their potential technological applications in the fields of optics and photonics. In addition to improved optical properties, the incorporation of metal ions into organic ligands makes it possible to control the intensity and polarization of the incident laser light. This makes organometallic complexes valuable and suitable candidates for nonlinear optical applications. In this study, a novel Zn(II) complex was synthesized by using 4-chloropyridine-2-carboxylic acid (4-Clpca) and 3-hydroxypyridine-2-carboxylic acid (3OHpca). The structural and spectroscopic properties of the Zn(II) complex were examined through XRD, FT-IR and UV-Vis techniques. The HOMO-LUMO energy range for the Zn(II) complex was found to be 4.7358 eV. Nonlinear optical parameters of Zn(II) complex were investigated as static and frequency-dependent (ω = 0.0856453887 au) methods. The dc-Kerr effect γ(-ω;ω,0,0) and EFSHG γ(−2ω;ω,ω,0) parameters were calculated as 13.04 × 10−36 esu and 2258.9 × 10−36 esu, respectively. The newly synthesized Zn(II) complex, which has weak second-order NLO properties due to the fully occupied electronic configuration of the Zn(II) ion, is quite promising in terms of its third-order optical properties.

Investigation on growth, crystal structure, third-order optical nonlinearity properties and DFT computational studies of novel proton transfer 3-aminopyridine P-nitrobenzoate P-nitrobenzoic acid (3APPNB) single crystal for third-order NLO applications

A new organic single crystal of 3-aminopyridine p-nitrobenzoate p-nitrobenzoic acid (3APPNB) with a size of 8 × 4 × 2 mm3 was grown by slow evaporation solution growth technique at room temperature using methanol solvent. The lattice parameter values were evaluated with the help of single crystal XRD and it confirms that the 3APPNB crystal belongs to triclinic crystal structure and the space group P-1. Crystal unit cell parameters are a = 9.3384(5) Å, b = 10.0403(5) Å, c = 11.094(6) Å, α = 109.4940(10)°, β = 93.964(2)°, γ = 99.890(2)° and V = 957.03 (9) (Å3) were determined. The 3APPNB crystal crystallizes in a centrosymmetric nature, triclinic system and space group P-1. SCXRD study shows that both the anion and the cation are interlinked to each other by two types of symmetrical intermolecular C–H…O and N–H···O hydrogen bonds. The crystalline nature and hkl phases have been determined using Powder XRD studies. The presence of different vibrational groups in the 3APPNB compound is examined by employing Fourier transform infrared (FT-IR) spectral analysis. UV–Vis-DRS spectral analysis signifies that the 3APPNB has a wide transmittance (98 %) and a cut-off wavelength of around 317 nm. The etch pit density (EDP) of 3APPNB crystal was examined by a chemical etching analysis. The thermal studies expose that 3APPNB is thermally stable up to 172 °C. The surface morphology of the 3APPNB is analyzed by SEM. The nonlinear properties like β, n2 and χ(3) were measured through the Z-scan analysis and the values were calculated to be 5.78 × 10−5 m/W, 8.05 × 10−12 m2/W) and χ(3) = 8.936 × 10−9. The third-order nonlinear optical (TONLO) χ(3) values are higher. The achieved TONLO χ(3) value when compared to other similar constituents is owing to the tarnish movement of π-electron configuration from the donor to an acceptor that makes the molecules highly polarized. The results reveal that the 3APPNB crystal finds applications in devices like optical switching and optical limiting. The quantum-chemical theoretical analyses are performed to measure the intrinsic properties of the 3APPNB molecules using DFT calculation. The band gap, orbital energy and second hyperpolarizability are also studied using changing the applied field. Furthermore, Quantum chemical calculations are used to obtain the MESP, HOMO-LUMO and first-order hyperpolarizability for the 3APPNB compound.

Nonlinear Third-Order Optical Properties in Polymer Ferroelectrics Doped with Ruthenium Phthalocyaninates

Nonlinear Third-Order Optical Properties in Polymer Ferroelectrics Doped with Ruthenium Phthalocyaninates

Synthesis of pyrene-based materials with third-order nonlinearity optical property by click chemistry modification

PurposeCurrently, conjugated nonlinear optical (NLO) materials suffer from the drawbacks of complex manufacturing process and high cost. To further study the NLO materials with cost-effective, it is necessary to prepare new NLO materials with satisfactory performance.Design/methodology/approachPyrene derivatives with good third-order NLO properties were synthesized by combining pyrene compounds with TCNE, TCNQ, F4-TCNQ and other molecular systems by clicking chemical method.FindingsThe pyrene derivatives were characterized by ultraviolet spectrum and Z-scan. The charge-transfer of the D-p-A structures plays a key role in the absorption peak shifts. And the third-order nonlinear absorption of the products revealed good third-order NLO susceptibilities.Research limitations/implicationsThe synthesis technology of pyrene derivatives is not mature enough and is in the preliminary exploration stage. So, the authors produced a relatively small number of samples and did not conduct a very comprehensive test.Practical implicationsThis novel pyrene derivative is suggestive and can promote the exploration and development of the third-order nonlinear materials.Originality/valueFour new pyrene derivatives were synthesized by selecting new molecular systems. Because of its good chemical properties and stable properties, it can be a reference for the development of third-order nonlinear materials in the future.

Z-scan measurements of the third-order optical nonlinearities and linear optical properties of 70TeO2 - 5MxOy - 10P2O5 - 10ZnO - 5PbF2 glasses doped with Er3+ ions modified by transition metals

The two photon absorption (TPA) coefficient (β), the nonlinear refractive index (n2 ), and the third order nonlinear optical susceptibility (χ<3> ) of tellurium dioxide glasses were investigated using the absorption spectra, normalized transmission, and Z-scan methods. We studied the influence of different transition metals, with and without the rare earth ion Er3+, on the nonlinear properties of these glasses. The experimental results show that (n2 ) and (β) are the highest for the glass consisting of cadmium oxide doped with rare earth ions. Consequently, the real and imaginary part of the third-order nonlinear optical susceptibility (χ<3>) is the highest for these materials. Moreover, the presence of Er3+ increased the NLO coefficients the all the examined samples. The Z-scan result confirms, the glasses exhibit self-focusing effects and the sign of the refractive nonlinearity is positive.

Crystal structures and third-order optical properties of three manganese(II) complexes constructed from N-heterocyclic and polycarboxylate ligands

Abstract Three new manganese(II) complexes, {[Mn(PTP)]2[Mn(PTP)(H2O)]}(BTA)2·2H2O (1), [Mn(PTP)(ODA)]2 (2), and [Mn(FTP)(ODA)]2·H2O (3), were synthesized by the reactions of manganese acetate and polycarboxylic acid in the presence of N-heterocyclic ligands (where PTP=4′-phenyl-2,2′:6′,2″-terpyridine, H3BTA=benzene-1,3,5-tricarboxylic acid, H2ODA=4,4′-oxydibenzoic acid, FTP=4′-(furan-2-yl)-2,2′:6′,2″-terpyridine). In complex 1, each BTA ligand serves as a μ 3-bridge to link three Mn(II) centers, whereas each Mn(II) center is coordinated by two BTA ligands. This connection mode results in a grid sheet. Complexes 2 and 3 have very similar molecular structures with Mn(II) centers connected by ODA ligands to result in ring-like arrays. We investigated the third-order nonlinear optical (NLO) properties of the three complexes by single beam Z-scan techniques. Complexes 1–3 exhibit strong third-order NLO reverse saturable absorption with NLO absorptive indices β=1.32×10−6, 3.01×10−6, and 9.42×10−6 m W−1, respectively. In addition, complex 1 shows all excellent self-focusing effect with an NLO refractive index of γ=1.25×10−12 m2 W−1. The third-order NLO susceptibility χ (3) of the three complexes were calculated as 47.55×10−8, 4.85×10−8, and 15.16×10−8 esu, respectively.

Study on growth, structural, optical, thermal and mechanical properties of organic single crystal ethyl p-amino benzoate (EPAB) grown using vertical Bridgman technique

Ethyl p-aminobenzoate (EPAB) single crystal was grown using vertical Bridgman technique (VBT). The crystal system of grown crystal was identified, and lattice parameters have been measured from the powder X-ray diffraction (PXRD). The optical transparency of EPAB single crystal was 55%, and the cut-off wavelength was found to be 337nm. The thermal stability of EPAB single crystal was analyzed by thermogravimetric analysis. Etching studie were carried out for the grown crystal using different solvents, and etch pit density (EPD) was calculated and compared. Vickers microhardness (Hv) measurements revealed that EPAB belongs to the category of soft material. The dielectric studies reveal that the dielectric constant and dielectric loss of grown crystal decreases with increasing frequency for various temperatures. The third-order nonlinear optical property of EPAB was investigated and compared with other organic crystals. The evaluation of third-order optical properties such as nonlinear refractive index (n2), nonlinear absorption (β) and third-order nonlinear susceptibility (χ3) have found to be in the range of 10−11m2/W, 10−4m/W and 10−5esu respectively. The Laser damage threshold energy of EPAB was measured using Nd: YAG laser. The blue emission of the grown crystal was identified by photoluminescence (PL) spectra measurements. The second harmonic generation (SHG) for the grown EPAB crystal was confirmed by Kurtz powder technique.

Second- and third-order nonlinear optical and quantum chemical studies on 2-amino-4-picolinium-nitrophenolate-nitrophenol: A phasematchable organic single crystal

The title compound, 2-amino-4-picolinium-nitrophenolate-nitrophenol (2A4PNN), has been synthesized and optical quality single crystals of 2A4PNN were grown by solution growth technique. The crystal structure was solved by single crystal X-ray diffraction method. The 2A4PNN molecule was found to possess intermolecular herringbone structure and to crystallize in orthorhombic crystal system with a noncentrosymmetric space group of Pna21 (Point group mm2). The functional groups of 2A4PNN were confirmed through FT-IR and Raman vibrational spectroscopic studies and NMR spectrum was recorded to study its molecular structure. The UV–Vis and photoluminescence spectra were recorded to explore its optical transmittance and emission properties respectively. The SHG efficiency and phasematchability were investigated through Kurtz and Perry powder technique using sieved/graded powders derived from polycrystals of 2A4PNN. The laser damage threshold studies of 2A4PNN single crystal were performed on (100) plane using a pulsed Nd:YAG laser (1064nm). The third-order optical properties of 2A4PNN single crystal were measured by Z-scan technique. In addition, the quantum chemical studies were performed on the isolated 2A4PNN molecule using density functional theory (DFT) calculations at the B3LYP/6-311++G (d,p) basis set.

Picosecond nonlinearity of GeO2–Bi2O3–PbO–TiO2 glasses at 532 and 1,064 nm

The third-order optical properties of GeO2–Bi2O3–PbO–TiO2 glasses at 532 nm and 1,064 nm were studied to evaluate their potential for optical limiting and all-optical switching. The Z-scan technique was used to determine the nonlinear (NL) refractive index, n 2, and the NL absorption coefficient, α 2, of samples with different amounts of the constituent oxides. Values of n 2 ≈ + 0.7 × 10−14 cm2/W at 1,064 nm and ≈+1.5 × 10−14 cm2/W at 532 nm were measured. The NL absorption coefficient, α 2, was smaller than the minimum that our apparatus can measure (α 2 < 0.01 cm/GW) in the near-infrared (1,064 nm); in the visible region (532 nm), we obtained α 2 ≈ 4.4 cm/GW. The set of NL parameters measured indicates the potential usefulness of the GeO2–Bi2O3–PbO–TiO2 glasses for all-optical switching at 1,064 nm and for optical limiting at 532 nm.

Microstructures and third-order optical nonlinearities of Cu2In nanoparticles in glass matrix

The Cu2In nanoparticles have been successfully formed in the glass matrix (Na2O–B2O3–SiO2) by using sol–gel method. The structural, compositional and morphological characterizations were performed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Results showed that Cu2In nanoparticles with hexagonal structure were well distributed in the glass matrix. The Cu2In nanoparticles were spherical shaped and highly monodispersed with an average size of about 30.28nm. The third-order optical properties of Cu2In nanoparticles embedded in glass matrix were investigated at 800nm by using femtosecond Z-scan measurements. The nonlinear refraction indices of these nanoparticles were measured in order of 10−16m2/W with negative sign and the nonlinear absorption coefficients were obtained in order of 10−10m/W with positive sign. A possible formation mechanism for Cu2In nanoparticles in the glass matrix was also discussed.

Theoretical study of electronic structure and third-order optical properties of beryllium–hydrocarbon complexes

A number of representative hydrocarbons and their complexes with beryllium metal have been considered for the theoretical study of their ground state structures and third-order nonlinear optical properties. The investigated beryllium complexes are mostly charge symmetric and found to be fairly stable. The third-order polarizability of these complexes has been calculated at the B3LYP optimized geometry by employing the HF and MP2 methods and also various DFT functionals for the 6-311++G (p,d) and aug-cc-pVTZ basis set. The NLO property of the chosen hydrocarbons is greatly enhanced on complex formation with Be. The most important characteristics of these complexes are the weaker linear absorption in the visible region and stronger two photon transitions in the ultraviolet region. The magnitude of cubic polarizability of such molecular complexes increases with increase of the linear polarizability. The calculated two photon contribution of second-hyperpolarizability of the Be-complexes is predicted to be rather significant which is also indicated by the maximum two photon cross section. The stronger two photon transitions are associated with the symmetric charge transfer either from the hydrocarbon moiety to beryllium atoms or vice versa. The Be-hydrocarbon complexes may be considered as the promising third-order NLO-phores due to their high optical transparency.

A New Copper(I) Complex Based on Imidazole and Triphenylphosphine Ligands: Synthesis, Structure, Third-Order NLO, and Fluorescence Properties

A new candidate [Cu(PPh3)2Him]Br (1, PPh3=triphenylphosphine, Him=1-H-imidazole) for nonlinear optical (NLO) materials has been synthesized and characterized crystallographically. The third-order NLO optical properties were measured by the Z-scan technique with an 8 ns pulsed laser at 532 nm. Compound 1 exhibits strong NLO absorptive abilities [a2=(61 +/- 5) x 10(-12)] and effective self-focusing performance [n2=(15 +/- 3) x 10(-18) m2.W-1] in 1.01 x 10(-4) mol.dm(-3) DMF solution. The compound also exhibits luminescence in DMF solution at room temperature and shows narrow emission with maximum at 382 nm. The electronic structure and photoluminescent process were investigated by means of TD-DFT calculations. The results suggest that the contribution to the frontier orbitals from the Cu?Br d bond plays a crucial role in its linear optical properties, and the origin of luminescence is attributable to the p*??n transitions.

Electron-Rich Iron/Ruthenium Arylalkynyl Complexes for Third-Order Nonlinear Optics: Redox-Switching between Three States

The new [(η(2)-dppe)(η(5)-C(5)Me(5))Fe(C≡C-1,4-C(6)H(4)C≡C)Ru(η(2) -dppe)(2) C≡C(C(6)H(5))] complex (3-H) and its hexanuclear relative [{(η(2)-dppe)(η(5)-C(5) Me(5))Fe(C≡C-1,4-C(6)H(4)-C≡C)Ru(η(2)-dppe)(2)(C≡C-1,4-C(6)H(4)C≡C)(3)(1,3,5-C(6)H(3))] (4) have been synthesized and characterized. The linear and cubic nonlinear optical properties of these compounds in their various redox states have been studied along with those of the analogous complexes [(η(2)-dppe)(η(5)-C(5)Me(5))Fe(C≡C-1,4-C(6)H(4)C≡C)Ru(η(2)-dppe)(2)R][PF(6)](n) (n=0-2; R=Cl, 2-Cl; R=C≡C(4-C(6)H(4)NO(2)),3-NO(2)). We show that molecules exhibiting large third-order nonlinearities can be obtained by assembling such dinuclear Fe/Ru units around a central 1,3,5-substituted C(6)H(3) core. These data are discussed with a particular emphasis on the large changes in their nonlinear (third-order) optical properties brought about by oxidation. Experimental and computational (DFT) evidence for the electronic structures of these compounds in their various redox states is presented using 3-H(n+) as a prototypical model. Single crystals of this complex in its mono-oxidized state (3-H[PF(6)]) provide the first structural data for such carbon-rich Fe(III) /Ru(II) heteronuclear mixed-valent (MV) systems. Although experimental evidence for the structure of the dioxidized states was more difficult to obtain, the theoretical study reveals that 3-H(2+) can be considered to have a biradical structure with two independent spins. The low-lying absorptions that appear in the near-infrared (NIR) range for all these compounds following oxidation correspond to intervalence charge-transfer (IVCT) bands for the mono-oxidized states and to ligand-to-metal charge-transfer (LMCT) transitions for the dioxidized states. These play a crucial role in the strong optical modulation achieved. The possibility of accessing additional states with distinct linear or nonlinear optical properties is also briefly discussed.

Anti-Resonant Interferometric Nonlinear Spectroscopy (ARINS) study of metal nanocluster-glass composites

Linear and nonlinear optical properties of copper and gold nanoclusters in fused silica glasses synthesized by 200 KeV Cu+ and 1.5 MeV Au+ ion implantation at a dose of 3x1016 ions/cm2 have been studied. UV-Vis spectroscopy has revealed prominent linear absorption bands at characteristic surface plasmon resonance (SPR) frequency signifying appreciable formation of copper and gold colloids in glass matrices. Third-order optical properties of the nanocluster-glass composite materials have been studied by Z-Scan and Anti Resonant Interferometric Nonlinear Spectroscopy (ARINS) techniques. The sign of the nonlinear refraction is readily obtained from Z-scan signature. The ARINS technique utilizes the dressing of two unequal-intensity counter-propagating pulsed beams with differential nonlinear phases, which occur upon traversing the sample. This difference in phase manifests itself in the intensity-dependent transmission. The nonlinear refractive index, nonlinear absorption coefficient and the real (and imaginary) parts of the third-order optical susceptibility have been extracted from ARINS data. Results of the investigation of the nonlinear refraction using the above two techniques and the possible mechanisms responsible for the nonlinear optical responses are presented in the current paper.

Enhanced nonlinear optical responses in metal–glass nanocomposites

The “engineered” nonlinear nanocomposite materials with extremely large values of optical Kerr susceptibility and fast temporal responses that can be precisely tuned to satisfy the requirements of switching applications is of current interest in photonics. Metal quantum-dot composite glasses can exhibit enhanced optical susceptibility, χ (3), whose real and imaginary parts are related to the intensity-dependent refractive index and two-photon absorption coefficient, respectively. Classical (dielectric) and quantum confinement effects come into play in the nonlinear optical responses of these nanocomposites. Metal nanocluster–glass composites have been synthesized by 200 keV Cu + and 1.5 MeV Au + ion implantations in fused silica glasses at a dose of 3 × 10 16 ions/cm 2, followed by thermal annealing in reducing atmosphere to promote cluster growth. UV–Visible spectroscopy has revealed prominent linear absorption bands at characteristic surface plasmon resonance (SPR) frequencies signifying appreciable formation of copper and gold colloids in glass matrices. Third-order optical properties of the composite materials have been studied by Z-Scan and Anti-Resonant Interferometric Nonlinear Spectroscopy (ARINS) measurements. The sign of nonlinear refraction is readily obtained from the Z-Scan signatures. The ARINS technique utilizes the dressing of two unequal-intensity counter-propagating pulsed light beams with differential nonlinear phases, which occur upon traversing the sample if it exhibits nonlinear optical response. This difference in phase manifests itself in the intensity-dependent transmission. The nonlinear refractive index, nonlinear absorption coefficient, the real and imaginary parts of the third-order optical susceptibility have been extracted.

Optical nonlinearities of Au nanocluster composite fabricated by 250 keV ion implantation

Metal nanocluster composite glass prepared by 250 keV Au ions into silica with dose of 1 × 10 17 ions/cm 2 has been studied. The microstructural properties of the nanoclusters are characterized by optical absorption spectra and transmission electron microscopy (TEM). Third-order optical properties of the nanoclusters are studied by the Z-scan technique under 1064 nm and 532 nm excitations. The nonlinear refraction index, nonlinear absorption coefficient, and the real and imaginary parts of the third-order nonlinear susceptibility are deduced. The results of the investigation of nonlinear refraction using the off-axis Z-scan configuration are presented and the mechanisms responsible for the nonlinear response are discussed. The third-order nonlinear susceptibility χ (3) of this kind of sample was determined to be 1.6 × 10 −7 esu at 532 nm and 1.3 × 10 −7 esu at 1064 nm.

A series of lead(II)/iodine hybrid polymers based on 1-D and 2-D metal–organic motifs linked by different organic conjugated ligands

The introduction of series of organic conjugated ligands into the Pb/I system leads to the formation of three lead(II)/iodine polymers [Pb2I4(dpdo)]n (1) (dpdo = 4,4′-dipyrdiyl-N,N′-dioxide), [PbI2(bipyO2)]n (2) (bipyO2 = 2,2′-dipyrdiyl- N,N′-dioxide) and {[PbI(Dhydql)]∙DMF}n (3) (Dhydql = deprotonated 8-hydroxyquinoline). In 1 and 2, both the organic and inorganic ligands are neutral. But the organic moiety in 3 is a conjugated negative ion and the inorganic component presents a 2-D layer arrangement. The organic ligands in this work serve as bridges to link the inorganic chain or layer to heighten the structural dimension. As expected, based on the bridge nature of an organic ligand, 1 features a 2-D arrangement of a staircase-like lattice sheet [Pb2I4(dpdo)]n, 2 exhibits a 1-D chain [PbI2(bipyO2)]n consisting of unprecedented twisted boat from seven-membered rings, and 3 presents a host–guest structure with DMF as guest molecules which are embedded in between adjoining inorganic–organic components. Furthermore, the compounds were further characterized with fluorescence, UV-vis spectra and third-order non-liner optical (NLO) properties.

Band-gap control optical Kerr effect and light self-focusing of semiconducting materials CdxHg1−xGa2S4

We report the dispersion of the optical Kerr effect and the wavelength-dependent critical power of light self-focusing for semiconductors CdxHg1−xGa2S4 in view of the calculated results from the density functional theory combined with an anharmonic oscillator model. It is shown that the third-order optical properties are controlled by the band gaps or cation contents of CdxHg1−xGa2S4, and it is indicated that the optical Kerr effect decreases and the critical power of light self-focusing increases as the x contents and band gaps increase for CdxHg1−xGa2S4.

INFRARED PHOTOREFRACTIVE COMPOSITES BASED ON POLYIMIDE AND J-AGGREGATES OF CYANINE DYE

Photorefractive composites sensitive to 1064 nm on a base of an aromatic polyimide containing J-aggregates of a thiacarbocyanine dye are presented. The molecules of the dye form the nanocrystalline J-aggregates that are responsible for photoelectric sensitivity at 1064 nm and nonlinear third-order optical properties. The net gain coefficient 266 cm-1 and the response time 0.09 s were achieved at an external electric field of about 15 V/μm.

Self-assembly and third-order optical properties of HgI 2 with linear and angular bipyridine ligands

Two bis(pyridyl) ligands: N, N′-bis(4-pyridyl)-1,4-benzenedicarboxamide (bpba) and N, N′-bis(3-pyridylformyl)imidazolidine-2-thione (bpit) have been designed and synthesized. Self-assembly of the linear ligand bpba and angular ligand bpit with HgI 2 results in a one-dimensional zigzag polymer {[HgI 2(bpba)] · 1.5CH 3OH} n ( 1) and a binuclear metallamacrocycle [HgI 2(bpit)] 2 · 3H 2O ( 2), respectively. Single crystal X-ray diffraction analyses reveal that in the crystal structure of 1 the linear ligand bpba is in transoid conformation, while in the crystal structure of 2 the angular ligand bpit coordinates with HgI 2 in cisoid conformation, the different geometries of the two ligands attribute to forming the dissimilar frameworks of two HgI 2 adducts. The determination of third-order nonlinear optical (NLO) properties of 1 and 2 in DMF solution shows that adducts 1 and 2 possess strong NLO self-focusing effect. The hyperpolarizability γ values of 1 and 2 are calculated to be 2.10 × 10 −29 and 3.24 × 10 −29 esu, respectively, which are comparable to those of some NLO materials. And the result indicates that the heavier atoms Hg and I together with the polymeric aggregation play an important role in determining their NLO properties.