Modeling nonlinear effects in Photonic crystal cavities
Photonic crystal devices have big potential for nonlinear optics, as they can confine light both spatially and temporally. However, a large number of nonlinear optical processes can occur in these systems, making it difficult to predict and understand how a device will respond to incident light.
Together with groups from the Centre for Advanced Photonics & Process Analysis (Cork Institute of Technology) and Tyndall National Institute as well as the University deglie Studie Pavia, we have now presented a numerical model, the can model and predict the dynamic behaviour of photonic crystal cavities.
We achieve this by modelling both the optical behaviour (including linear and nonlinear absorption) and the thermal behaviour of the system. For thermal modelling, we split the device into ring-shaped slices and model the heat flow through the device. Combing this thermal model with rate equations for the intra-cavity energy, free carrier density and the nonlinear changes to the refractive index allows us the finally model and predict the behaviour of the cavity, both in the steady-state and in dynamic excitation.
This work, which is published in Physical Review B will form the foundation of future work in the use of Photonic crystal cavities for low-power nonlinear optics.