ABSTRACT
The search for new materials with desirable nonlinear optical (NLO) prop erties has accelerated in the last few years, with attention shifting from inorganic to organic materials. Inorganic materials are robust, have a wide optical transparency range, and are easy to obtain as large crystals, but suffer from slow response times (where the NLO effect arises from lattice distor tions, this can be of the order of nanoseconds), difficulty of fabrication, and little architectural flexibility. Organic materials have therefore come to the fore: the NLO effects arising from electron polarization have response times of the order of femtoseconds, organic materials can be readily pro cessed to be cast as thin films, and organic compounds possess structural diversity and architectural flexibility which is useful for optimizing NLO responses. Organics suffer from some disadvantages, though, including lower thermal stability than inorganics, and the transparency/NLO efficiency trade off. Increasing attention has been given to organometallic complexes over the past decade. Organometallic complexes possess the
advantages of organic compounds, but with significant additional advan tages: design flexibility (the possibility of varying metal, oxidation state, ligands, and coordination geometry), and the prospect of examining the NLO merit of organic groups which have limited or no stability in the absence of a metal (e.g., carbenes).
