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Abstract: This review provides a survey of nonlinear optical (NLO) chromophores and materials incorporating them which have been demonstrated over the last several years. Conventional polymeric materials, dendrimers, and other material design approaches are reviewed. Macroscopic nonlinear optical properties are introduced mainly in terms of second-harmonic generation (SHG) and the electro-optic (EO) effect. The temporal and thermal stability of nonlinear optical properties are also discussed. The review begins with a brief introduction explaining overall principles relating to the origin of second-order nonlinear optical properties. The structure of NLO materials, methods for their characterization, and structure–property relationships are also introduced. Much current research is aimed at optimizing microscopic nonlinearity in well-defined heterocyclic NLO chromophores which are then embedded in materials such as polymers, dendrimers, etc. Strong electron density donor and acceptor groups are connected through an efficient π-electron conjugative bridge to yield a highly electronically asymmetric and hyperpolarizable NLO chromophore. This review highlights the design and synthesis of recent chromophores that simultaneously exhibit large molecular hyperpolarizability, and low optical absorption at an operating wavelength, in addition to good processability and thermal/photochemical stability. Although NLO chromophores have been designed to exploit both dipolar and octupolar symmetry, the former has exhibited the strongest potential for the development of practical NLO devices. Organic materials based on polymers and dendrimers containing dipolar chromophores are mainly demonstrated for nonlinear optics. Experimental results corresponding to such dipolar compounds are mainly considered in this review. In addition, new strategies to improve thermal stabilities are also discussed herein. [Copyright &y& Elsevier]

Abstract: A new noncentrosymmetric three-dimensional tellurite with second-order nonlinear optical property, BaMo2Te2O11(H2O), was synthesized by the hydrothermal reaction of Ba(OH)2, TeO2 and MoO3. It is characterized by single-crystal X-ray diffraction and spectral properties. The compound contains {Mo(1)Mo(2)O10} n infinite spiral chains, which are linked into infinite anionic layers along ab plane by Te(1)O5 and Te(2)O4 polyhedra. Ba2+ cations are intercalated between the layers. Energy band of the compound is calculated and analyzed, the band gap is 3.23eV, it indicates the solid-state compound of BaMo2Te2O11(H2O) is an insulator and the value is consistent well with the experimental value of 3.18eV. [Copyright &y& Elsevier]

Nonlinear optical (NLO) properties of three chiral smectic liquid crystals were investigated by Hyper-Rayleigh Scattering (HRS) and the Second-Harmonic Generation (SHG) methods. The HRS measurements of two compounds (MHPOBC and D16), with the biphenyl unit in their center, in solution demonstrate the quadratic NLO activity. The third compound (D17), having three isolated phenyl rings in the core, does not exhibit the NLO activity. The NLO properties in smectic phases of all investigated compounds have been also studied by wide-field second-harmonic and two-photon fluorescence microscopy confirming noncentrosymmetry for compounds with biphenyl π coupling (MHPOBC and D16). • Nonlinear optical properties of chiral smectic liquid crystals reported. • SHG and 2PF microscopy were used to obtain images of ferroelectric liquid crystals. • Comparison of NLO responses in ferro- and antiferroelectric SmC phases • Presence of p-conjugated biphenyl core important for quadratic NLO activity [ABSTRACT FROM AUTHOR]

• Thiosemicarbazidezincchloride (TSCZC) single crystals were grown via solution slow evaporation technique. • The optical band gap was around 4.54e V with 85 % of transmittence. • TSCZC crystal show 0.317 times SHG efficiency and can thermally stable upto 148 °C. • Non linear optical parameters β, n 2 and χ (3) were determined through Z scan analysis. • The grown, noncentrosymmetric NLO crystal can be applied for optic and photonic device applications. In this present work, we report the successful growth of zincchloride added thiosemicarbazide(TSCZC) crystals grown by slow solvent evaporation at room temperature. Good crystaline Pnma space group with orthorhombic structured non centrosymmetric crystal verified by powder-x ray diffraction was also characterised by Fourier Transformed Infrared, Differential Scanning Calorimetry and dielectric analysis to identify the presence of various functional groups with bonding types, thermal stability, and dielectric properties. Vast transparency in the whole visible region with 4.54 eV band gap for λ min = 273 nm suggests the utility of the crystal for non linear optical applications. Kurtz-Perry SHG test shows 0.317 times higher efficiency than reference KDP.Z scan analysis exhibits higher third order nonlinear optical susceptibility χ(3) = 3.266 × 10 - 6 esu with non linear refractive index(n 2) = 3.33 × 10 - 9 cm2/W.Self defocusing nature and Reverse Saturation Absorption(RSA) styles are the added advantages of the grown TSCZC metal organic crystal for its utilisability in Non Linear Optical and photonic device applications. [ABSTRACT FROM AUTHOR]