Nonlinear Optical Properties

Linear and Nonlinear Polarizability: a Primer Second-Order Nonlinear Optical Processes in Molecules and Solids Third-Order Nonlinear Optical Effects in Molecular and Polymeric Materials Nonlinear Optical Properties of Molecules and Materials Electronic Hyperpolarizability and Chemical Structure Electrooptic Polymer Waveguide Devices: Status and Applications Waveguiding and Waveguide Applications of Nonlinear Organic Materials Nonlinear Optical Materials: The Great and Near Great Donor- and Acceptor-Substituted Organic and Organometallic Compounds: Second-Order Nonlinear Optical Properties Use of a Sulfonyl Group in Materials for Nonlinear Optical Materials: A Bifunctional Electron Acceptor Organic and Organometallic Compounds: Second-Order Molecular and Macroscopic Optical Nonlinearities Chemistry of Anomalous-Dispersion Phase-Matched Second Harmonic Generation Applications of Organic Second-Order Nonlinear Optical Materials Chromophore-Polymer Assemblies for Nonlinear Optical Materials: Routes to New Thin-Film Frequency-Doubling Materials Novel Covalently Functionalized Amorphous *y^2 Nonlinear Optical Polymer: Synthesis and Characterization Second-Order Nonlinear Optical Polyphosphazanes Molecular Design for Enhanced Electric Field Orientation of Second-Order Nonlinear Optical Chromophores Nonlinear Optical Chromophores in Photocrosslinked Matrices: Synthesis, Poling, and Second-Harmonic Generation Thermal Effects on Dopant Orientation in Poled, Doped Polymers: Use of Second Harmonic Generation Organic Polymers as Guided Wave Materials Observing High Second Harmonic Generation and Control of Molecular Alignment in One Dimension: Cyclobutenediones as a Promising New Acceptor for Nonlinear Optical Materials Strategy and Tactics in the Search for New Harmonic-Generating Crystals Development of New Nonlinear Optical Crystals in the Borate Series What is Materials Chemistry? Defect Properties and the Photorefractive Effect in Barium Titanate Defect Chemistry of Nonlinear Optical Oxide Crystals From Molecular to Supramolecular Nonlinear Optical Properties Control of Symmetry and Asymmetry in Hydrogen-Bonded Nitroaniline Materials Molecular Orbital Modeling of Monomeric Aggregates in Materials with Potentially Nonlinear Optical Properties Strategies for Design of Solids with Polar Arrangement Ferroelectric Liquid Crystals Designed For Electronic Nonlinear Optical Applications Model Polymers with Distyrylbenzene Segments for Third-Order Nonlinear Optical Properties Composites: Novel Materials for Second Harmonic Generation Clathrasils: New Materials for Nonlinear Optical Applications Inorganic Sol-Gel Glasses as Matrices for Nonlinear Optical Materials Intrazeolite Semiconductor Quantum Dots and Quantum Supralattices: New Materials for Nonlinear Optical Applications Small Semiconductor Particles: Preparation and Characterization Synthetic Approaches to Polymeric Nonlinear Optical Materials Based on Ferrocene Systems Transition Metal Acetylides for Nonlinear Optical Properties Third-Order Near-Resonance Nonlinearities in Dithiolenes and Rare Earth Metallocenes Nonlinear Optical Properties of Substituted Phthalocyanines Nonlinear Optical Properties of Substituted Polysilanes and Polygermanes Design of New Nonlinear Optic-Active Polymers: Use of Delocalized Polaronic or Bipolaronic Charge States New Polymeric Materials with Cubic Optical Nonlinearities: From Ring-Opening Metathesis Polymerization Polymers and an Unusual Molecular Crystal with Nonlinear Optical Properties Quadratic Electrooptic Effect in Small Molecules Third-Order Nonlinear Optical Properties of Organic Materials

Second-order nonlinear optical (NLO) materials have drawn enormous academic and technological attention attributable to their indispensable role in laser frequency conversion and other greatly facilitated applications. The exploration of new NLO materials with high performances thus has long been an intriguing research field for chemists and material scientists. However, an ideal NLO material should simultaneously satisfy quite a few fundamental yet rigorous criteria including a noncentrosymmetric structure, large NLO coefficients, desired transparent range, large birefringence, high laser damage threshold, and availability of a large-size single crystal. Therefore, the identification of promising compound systems, targeted design, and experience-based syntheses are crucial to discover novel NLO materials working in the spectral region of interest. As an important family of mixed-anion compounds, versatile metal oxyhalides containing metal-centered oxyhalide functional units ([MOmXn] (X = F, Cl, Br, and I)) are becoming a marvelous branch for interesting NLO materials. Especially, when the central metals are d0/d10 transition metals or heavy post-transition metals, a number of novel NLO materials with superior functionalities are expected. Our thorough review on the recent achievements of metal oxyhalides for NLO materials are divided into the fast-growing NLO metal oxyhalides with single type halogen anions and the newly identified NLO metal oxyhalides with mixed halogen anions. Here we mainly focus on the design strategy, structural chemistry, NLO-related properties, and structure–property correlation of the metal oxyhalides with relatively large NLO responses. We hope this review can provide an insight on the rational design and future development of emerging metal oxyhalides for NLO and other applications.

Light-adjustable third-order nonlinear absorption properties based on a series of hydrazone compounds

Organic materials that exhibit large real third-order optical nonlinearities, |Re(χ(3))|, and that also have low linear and nonlinear losses at telecommunication wavelengths may be useful for a range of all-optical signal-processing (AOSP) applications. Based on their solution linear and nonlinear optical characteristics, polymethine dyes in general, and chalcogenopyrylium-terminated heptamethines in particular, are a promising class of materials for AOSP, but the translation of their microscopic nonlinearity to device-relevant materials is hindered by significant aggregation of the molecules in high-chromophore density films.[1] An approach to minimize aggregation these dyes, in which bulky and rigidly out-of-plane groups are introduced both in the center of the polymethine bridge and on the heterocyclic end groups, has been developed and can lead to thin-film materials exhibiting combinations of large |Re(χ(3))|, large two-photon figure-of-merit, and low linear loss that are suitable for AOSP.[2] [1] Hales J. M., Matichak J., Barlow S., Ohira S., Yesudas K., Bredas J.-L., Perry J. W. and S. R. Marder, Science, 2010, 327, 1485. [2] Barlow S., Bredas J.-L., Getmanenko Y. A., Gieseking R. L., Hales J.M., Kim H., Marder S.R., Perry J. W., Risko C., Zhang Y., Materials Horizons, 2014, 1, 17.

Organic materials with large third-order nonlinearities in the near-infrared spectral regime are critical in the development of photonic devices to be utilized in all-optical signal processing. We have developed polymethine materials, specifically bisdioxaborine-terminated polymethine dyes, which possess large ultrafast third-order nonlinearities and low nonlinear loss all in the near-infrared spectral regime. An extended bisdioxaborine polymethine anion exhibited the largest value of gamma (third-order microscopic nonlinearity) at 1.3 mum (|gamma| = 5.7 x 10-32 esu) and showed no characteristics of symmetry breaking, unlike other polymethines of similar lengths. A neat film of this molecule maintained relatively low linear loss in the near-infrared and showed a large third-order macroscopic nonlinearity at 1.3 mum (|chi(3)| = 3.6 x 10-10 esu), with a temporal response of less than 8 ps. Furthermore, the real part of chi(3) was nearly an order-of-magnitude larger than the imaginary component. Consequently, this material exhibited good figures of merit for all-optical signal processing throughout the entire telecommunications band.

Physicochemical properties of 2-amino-5-methylpyridinium 3-carboxy-4-hydroxybenzenesulfonate single crystal: An efficient material for optoelectronic applications

Control of third-order nonlinear optical properties by coordination metal change based on a series of metal organic chains

Defect engineering of second-harmonic generation in nonlinear optical semiconductors

Crystal growth is an important branch of solid state physics and material science. The Growth of Nonlinear Optical (NLO) materials crystals receives much importance nowadays because NLO materials have various applications in modern technologies like Laser technology, optoelectronics, and fiber optics, etc. Potassium dihydrogen phosphate (KDP) is a well known nonlinear optical (NLO) material with different applications. Since most of the amino acids exhibit NLO property, it is of interest to dope them in KDP. In the present study, amino acid L-Phenylalanine doped KDP crystals have been grown by slow evaporation solution growth technique. In present study powder XRD analysis was carried out which show that pure and L-Phenylalanine doped KDP crystals have tetragonal symmetry. The doping of L-Phenylalanine was confirmed by FT-IR and paper chromatography. Thermal analysis has been performed on the grown crystals.The SHG efficiency of L-Phenylalanine doped KDP crystals was found to be increasing with a doping concentration of L-Phenylalanine. Introduction. The demand for high quality large size KDP single crystal increases due to its application as frequency conversion crystal in inertial confinement fusion [1, 2]. KDP belongs to scalenohedral (twelve faced) class of tetragonal crystal system [3]. With the aim of improving the second harmonic generation (SHG) efficiency of KDP, researchers have attempted to modify KDP crystals by doping different types of impurities. The non-linear optical (NLO) and other properties of the crystal have been improved by doping of organic impurities [4-9]. KDP doped with amino acids like L-glutamine acid, L-gistidine, and L-valine was reported [10]. Kumaresan et al. [11] has reported the thermal dielectric properties of amino acids such as L-glutamic acid, L-histidine and L-valine doped KDP crystals. They found improved NLO properties of the KDP crystal and modifications in the structural, optical, mechanical, and electrical properties, too. Parikh [12] has reported the SHG efficiency of L-arginine doped KDP crystal. Kumaresan et al. [13] has also reported the effect of metal ion and amino acid doping on the optical properties of KDP crystal. Muley et al. [5] has studied thermal, NLO properties of KDP crystal doped with L-arginine and L-alanine. Suresh Kumar and Rajendrababu [6] studied the effects of L-arginine, L-histidine and glycine on the growth of KDP single crystals and observed that addition of amino acid enhances transparency, thermal stability and NLO efficiency of KDP crystals. Amino acid family crystals are playing an important role in the field of non-linear optical organic molecular crystal. Among them L-Phenylalanine (LPA) with chemical formula (C6H5CH2CH(NH2)COOH) is the α-amino acid with a non-reactive hydrophobic benzyl side chain. The physical, chemical and non-linear optical properties of KDP are enhanced by adding optically active amino acids as dopants.The growth and characterization of Single crystals of KDP doped with amino acids namely glycine, arginine, alanine, tryptophan, histidine have been reported earlier [5-8]. In the present work, single crystals of Potassium dihydrogen phosphate (KDP) added

Synthesis and third-order optical nonlinearities of hyperbranched metal phthalocyanines

Third-order optical nonlinearities in semi-parabolic quantum wells are studied. The third-harmonic generation coefficient is obtained by using compact-density-matrix approach and iterative method, and the numerical results are presented for spical semi-parabolic quantum wells. The very large third-harmonic-generation coefficient is obtained in this semi-parabolic quantum wells and it is over 10 times bigger than that obtained in parabolic quantum wells. In addition, the relations among the third-harmonic-generation coefficient, the photons energy, the parabolic confinement frequency, and the relaxation constant are also investigated, respectively.

A hot topic in materials science is to search for nonlinear optical (NLO) crystals, which are indispensable in current laser technology, future optical information, and precision measurements. In the period of the 1980s and 1990s, the anionic group theory proposed by Prof. Chuangtian Chen has greatly promoted the inventions of BaB2O4 (BBO), LiB3O5 (LBO), and KBe2BO3F2 (KBBF) which are widely applied in the ultraviolet (UV) spectral region today. From the beginning of this century, the rapid development of laser science and technology urgently demands new NLO crystals for wider application ranges. However, commercial NLO crystals in deep-UV and mid-infrared (mid-IR) regions are scarce. The challenge arises from the stringent criteria at various wavelengths and inefficient exploration strategy. As such, more comprehensive and quantitative theoretical guidance is necessary to improve and supplement the NLO structure-property understandings. Benefiting from high-performance computing resources, first-principles design and simulations came into being, which is more applicable to the understanding of mid-IR NLO mechanism and suitable for the efficient design of new NLO structures for current needs. In the past decade, a complete set of computational research programs based on first-principles simulations have been developed, which have promoted the development of NLO crystals in the deep-UV and mid-IR regions, and guided the subsequent and further experimental explorations. Based on our developed first-principles materials design system, the discoveries of NLO materials have ranged from basic theoretical design to rapid-prototyping and final experimental synthesis. In this Account, we will concisely summarize our ab initio guided and forward-looking studies on NLO crystals, which are our original contributions to this field and can be consulted by other material fields. First, we will review the development of NLO crystals and the important features of NLO materials. Second, we will summarize the important role of computer-aided design in advancing the NLO material field and our developed NLO material design system based on the first-principles simulations. Third, we will introduce the first-principles design for new deep-UV NLO crystals using two novel design proposals, i.e., interlayer cationic replacement and intralayer anionic substitution. Meanwhile, we will illustrate the hierarchical molecular engineering optimizations for mid-IR NLO crystals by illustrating an extended mid-IR NLO family pedigree, from which many promising mid-IR NLO systems were predicted theoretically and confirmed experimentally. Finally, we will give an outlook to explore new functional NLO crystals guided by our first-principles design and simulations. We believe that the computer-assisted exploration for new functional NLO materials is useful for understanding structure-property relationships and can provide researchers with a new approach to cost-effective and data-driven materials design.

Nonlinear optical (NLO) materials are of great importance in modern optics and industry because of their intrinsic capability of wavelength conversion. Bandgap is a key property of NLO crystals. In recent years, machine learning (ML) has become a powerful tool to predict the bandgaps of compounds before synthesis. However, the shortage of available experimental data of NLO crystals poses a significant challenge for the exploration of new NLO materials using ML. In this work, we proposed a new multi-fidelity ML approach based on the multilevel descriptors developed by us (Z.-Y. Zhang, X. Liu, L. Shen, L. Chen and W.-H. Fang, J. Phys. Chem. C, 2021, 125, 25175-25188) and the gradient boosting regression tree algorithm. The calculated and experimental bandgaps of NLO crystals were collected as the low- and high-fidelity labels, respectively. The experimental values were predicted based on chemical compositions of crystals without prior knowledge about crystal structures. The multi-fidelity ML model overcame the performance of single-fidelity predictor. Furthermore, it was observed that less accurate predictions on the low-fidelity label may result in more accurate prediction on the high-fidelity label, at least in the present case. Using the multi-fidelity ML model with the best performance in this work, the mean absolute error on the test set of experimental bandgaps was 0.293 eV, which is smaller than that using the single-fidelity model (0.355 eV). It is far from perfect but accurate enough as an effective computational tool in the first step to discover novel NLO materials.

Structural, optical, thermal, dielectric, laser damage threshold and Z-scan studies on fumarate salt of creatinine: A promising third-order nonlinear optical material

Two new Schiff-base modified vanadium complexes, [VIVO(C7 H5O)2(N2C6H10)] (1) and [VVO2(C7H5O)(N2C6H12)] (2), were synthesized under hydrothermal conditions, in which salicylaldehyde and cyclohexanediamine were used directly to form Schiff-base ligands during the reactions. The structures of 1 and 2 were characterized by EA, FT-IR, UV-vis, SCXRD and PXRD, EPR spectroscopy and magnetic susceptibility measurement. Due to the good optical activity of Schiff-base ligands and the existence of conjugated benzene rings in 1 and 2, the delocalized electronic effects between Schiff-base ligands and vanadium can be improved. Therefore, the third-order non-linear optical (NLO) properties of these complexes were investigated. The results of the open aperture Z-scan tests show that the two-photon absorption (TPA) cross-sections (σ) of the complexes are 1033 and 1041GM, respectively, which indicated that they both have potential applications as NLO materials.