Capturing light pulses into a pair of coupled photonic crystal cavities

Stopping light in technologically relevant systems, such as photonic crystals, has important implications for various optical information processing tasks, including buffering and nonlinear signal processing. The initial theoretical proposal for such a system requires tuning many resonators and has not yet been implemented. Recent experimental studies instead used either one or two dynamically tuned resonators, and have demonstrated partial capture of pulses. In a previous paper, using coupled mode theory, we have proposed a general theoretical condition for completely capturing pulses with the use of several cavities. Related work on pulse capturing in atomic media with small optical depth has been considered in Ref. 8. In this letter we numerically implement the condition described in Ref. 7 by simulating a two-dimensional photonic crystal system as shown in Fig. 1 a using finitedifference time-domain FDTD methods. Our simulation indeed demonstrates near-complete pulse capture. The simulations have also provided a validation of the coupled mode theory model shown in Fig. 1 b . We start by using this coupled mode theory model to highlight the essential physics of pulse capture and release in a few dynamically tuned cavities. For this system, the coupled mode theory equations are