Light sculpts three-dimensional crystals in nonlinear optical materials

Engineering and guiding light by artificial structures is one of the most actual questions in photonics, allowing optical information processing to open new horizons for waveguiding, storing, and processing light.

Three-dimensional structures have been a challenge up to now, either due to the complex formation method or the lack of appropriate material. Especially the creation complex quasi crystals that have a number of advantages features as e.g. better control of the transmission features by larger und more homogeneously distributed band gaps, is an actual challenge.

A combined effort of researchers from “Institut für Angewandte Physik” and “Center for Nonlinear Science”, Westfaelische Wilhelms-Universitaet Muenster (WWU), Germany and Department of Physics, Indian Institute of Technology Delhi, India, shines the way for a versatile approach to form complex 3D quasi-crystallographic photonic crystals structures formed by light. The researchers have experimentally demonstrated for the first time the creation of 3D photonic crystals and quasicrystals with a plethora of geometries and forms purely by the action of light in a nonlinear optical – so-called photorefractive- material, which allows reconfigurable as well as scalable crystal and quasicrystal formation.

“Creating photonic crystals by light itself is a wonderful example on how light matter interaction can be exploited” said Prof. Dr. Cornelia Denz, Director of the Institute for Applied Physics and Leader of the Center for Nonlinear Science, WWU, who supervised the research team. “Novel three-dimensional photonic structures with reconfigurable features for photonic device integration is a hot topic among the research community. Exploiting the principle of 'light is controlling light', our complex three-dimensional photonic quasicrystals will allow forming a reconfigurable platform to investigate advanced nonlinear light-matter interactions in higher spatial dimensions” emphasized Prof. Denz.

By modifying a laser light beam by a spatial light modulator, and subsequently sculting a nonlinear optical material with this light structure, the research team could easily generate artificial refractive index photonic structures. Typically, neither any additional optical component nor manipulation of the experimental setup is involved while reconfiguring from one structure to another.

“The success of this versatile experimental innovation paves the way to the mass production of scalable large area quasi-crystallographic photonic templates. This in turn points to the realization of complex artificial photonic bandgap structures for promising applications as e.g. highly efficient flat-panel displays with customized angular emission,” commented Dr. Joby Joseph, Associate Professor of Physics, Photonics Group, Indian Institute of Technology Delhi, India, who coordinated the collaborative efforts from India.

The researchers elaborate their work in the journal “Advanced Materials” (Vol.22, No.3, pp.356-360; DOI: 10.1002/adma.200901792) where Jolly Xavier as the lead author together with Martin Boguslawski, Patrick Rose, Dr. Joby Joseph, and Prof. Dr. Cornelia Denz, describe their research details. The research was partially funded by German Academic Exchange Service.