Optics of nanocomposite materials

This special issue aims to consolidate and capture the breadth of current research at the forefront of photonic nanocomposite materials. The selection of articles from multi-component, hybrid polymer-liquid crystal materials to nanocrystalline materials reflects different strands of research pursued in that area. Both review and research papers, covering basic and applied research topics, are presented. Photonic nanocomposite materials are generally constructed by embedding an optically functional nanosized guest material (e.g. nanoparticles, nanocrystals and molecules) into an optically transparent host matrix such as organics (e.g. (photo)polymers, polymer blends, liquid crystals) or inorganic solids (e.g. glasses and ceramics). The addition of the guest material to the host matrix can yield significant improvement and modification in their mechanical, thermal, transport and optical properties over bulk materials. As a result, high-performance photonic functionalities, with environmentally stable optical characteristics, can be achieved. In addition, nanocomposite materials can be tailor-made via the control of their linear optical properties, such as the refractive index and absorption as well as their laser, electro-optic, and nonlinear optical properties. For example, the incorporation of liquid crystalline droplets in polymers gives electrically controllable light scattering characteristics, ideally suited for display and optical switching applications. Dispersing inorganic or organic nanoparticles in optical materials leads to a strong response to incident light. Indeed, ferroelectric nanoparticles in cholesteric liquid crystals enhance the electro-optic response of the mixture. In photopolymers, nanoparticles make the formation of a high-contrast holographic grating possible, which should prove useful for applications such as optical elements and data storage. Moreover, nanoparticles dispersed in photopolymer can be assembled by light, providing the realization of multi-dimensionally structured materials, highly relevant for photonic and electronic applications. The local-field effects in nanostructured materials can provide a large enhancement of the nonlinear optical response and the improvement of the light amplifying properties. These areas are represented in this special issue, along with contributions to modelling of photonic crystal structures and holographic grating formation in polymers. Because nanocomposite materials provide a new method to improve the environmental stability of materials, as well as interesting optical properties, they should open new routes for applications in photonics. The Guest Editors would like to thank all the authors for their contributions and the referees for their efforts in reviewing the manuscripts. We would also like to thank the Editors of Journal of Optics A for suggesting this special issue and Julia Dickinson, the Publishing Editor, for her invaluable assistance.