Photonics is being labelled by many as the technology for the 21st century. Because of the structural flexibility both at the molecular and bulk levels, organic materials are emerging as a very important class of nonlinear optical materials to be used for generating necessary nonlinear optical functions for the technology of photonics. Since the last NATO advanced research workshop on "Polymers for Nonlinear Optics"held in June 1988, at Nice - Sophia Antipolis, France. there has been a tremendous growth of interest worldwide and important development in this field. Significant progress has been made in theoretical modeling, material development, experimental studies and device concepts utilizing organic materials. These important recent developments provided the rationale for organizing the workshop on "Organic Materials for Nonlinear Optics and Photonics" which was held in La Rochelle, France, in August 1990. This proceeding is the outcome of the workshop held in La Rochelle. The objective of the workshop was to bring together scientists and engineers of varied backgrounds working in this field in order to assess the current status of this field by presenting significant recent developments and make recommendations on future directions of research. The workshop was multidisciplinary as it had contributions from chemists, physicists, materials scientists and device engineers. The participants were both from industries and universities. The workshop included plenary lectures by leading international scientists in this field, contributed research papers and a poster session. Panel discussion groups were organized to summarize important developments and to project future directions.

Inhalt
Towards the Calculations of Polarizabilities of Infinite Polymeric Chains.- Conjugated Polymers: On the Parallel Between the Electrical Conduction Mechanism and the Nonlinear Optical Response..- On the Calculation of the Hyperpolarizabilities of Organic Molecules by the Sum Over Virtual Excited States Method.- Impact of Electron Quantum Confinement on Optical Nonlinearities.- Structural and Electronic Properties of Push-Pull Conjugated Molecules: A Theoretical Investigation of p-Amino-p' Nitrodiphenylacetylene Compounds.- Polar and Non-Polar Organic Molecules, Crystals and Langmuir-Blodgett Films for Quadratic Nonlinear Optics.- Design Considerations for Multi Component Molecular-Polymeric Nonlinear Optical Materials.- Empirical Systematics of Molecular Quadratic Optical Polarizability.- Surface and Adsorbate Analysis by Second-Harmonic Generation.- New Molecular Design for Noncentrosymmetric Crystal Structures: Lambda shape Molecules for Frequency Doubling.- Study of Novel Class of Second Order Nonlinear Optical (NLO) Polyurethanes.- EFISH Studies of Stilbene- and Thiophene-Derivatives.- Surface Second Harmonic Generation in Total Reflection.- Second Order Hyperpolarisabilities and Conformations of Functionalized Copolymers.- NPNN: A New Ferromagnetic Optically Nonlinear Organic Compound.- Second Harmonic Generation from Amphiphilic Dyes at the Air-Water Interface.- Strategy for Optimization of Molecular Materials for Nonlinear Optics and Photonics.- Excited State Nonlinear Optics.- Influence of Conformation on Two-Photon Spectra of Polyalkylthiophene.- Advances in the Synthesis of Electroactive Materials and in the Characterisation of Mechanisms of NLO Activity..- Thiophene Based Conjugated Polymers: THG Spectroscopy and Transient Photogenerated Polaron Enhancementof Cubic Optical Nonlinearity.- Electronic Properties of Conjugated Polymers with Aromatic or Hetero-Aromatic Cycle.- Oriented Conjugated Polymers for Nonlinear Optics: Properties of a Liquid Crystalline Polyacetylene. Epitaxial Growth of a Polydiacetylene PDCH.- Third Order Nonlinear Optical Effects in Conjugated Polymers and Dye Systems.- Phase Conjugation under Picosecond Two-Photon Absorption in Polydiacetylenes.- Relaxation of One- and Two-Photon Excitations in a Polydiacetylene Red Form: Frequency and Phase Resolved Analysis.- Excited State Absorption and Optical Limiting in Solutions of Metallophthalocyanines.- Third Order Optical Nonlinearities in Metal Dithiolate Complexes.- Nonlinear Optical Studies of Transition Metal Containing Conjugated Organic Monomeric and Polymeric Systems.- Organic Thin Films for Quadratic Optics.- Poled Epoxy Polymers for Optoelectronics.- Poled Glassy Polymers and Metallated Macrocycles for Nonlinear Optics.- Electrooptic Organic Waveguides: Optical Characterization.- Optoelectronic Devices with Nonlinear Polymers.- Two-Photon Absorption in Polydiacetylene Based Waveguides: Its Origin and Its Consequences..- Second Harmonic Generation from Langmuir Layers and Langmuir-Blodgett Films.- An Adaptation of the Prism-Film Coupler Method Used to Study PVA/Chrysoidin Non-linear Waveguides.