Periodic structures for nonlinear optics

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Nonlinear optics is the term used to refer to the interaction of light and matter where the strength of the interaction depends on the optical intensity. The nonlinear effects of interest in this research program are those based on the change in refractive index induced by a high intensity laser beam. Such effects have been used to demonstrate a range of all-optical switching and signal processing devices. However, the relatively small nonlinear coefficients present in most materials result in prohibitively high optical power levels and limit the potential applications of such devices. Periodic structures have fascinated scientists and engineers for decades because of their novel optical properties. For example the colors observed in opal crystals and butterfly wings are due to the underlying periodic structures and not a consequence of pigmentation. One of the associated benefits of such periodic structures is that they lead to a high degree of confinement for light and as a result make nonlinear optical interactions more efficient. The challenge to be overcome is to engineer periodic structures which will enhance nonlinear optical interactions and which in the long term will result in practical all-optical switching and signal processing devices. The aim of this application is to combine current and developing nonlinear materials with engineered, periodic photonic structures to demonstrate novel all-optical functionalities. In addition, the use of optical gain is such periodic structures will  be investigated with a view to further reducing the optical power requirements.