Figure 1

Schematic of a tunable microcavity system used to time reverse light. The disks represent cavities, and the arrows indicate available evanescent coupling between the cavities. The system consists of two subsystems $A$ and $B$ represented by blue and red colors. The dashed box indicates a unit cell.Reuse & Permissions

Figure 2

${\omega }_A$ and ${\omega }_B$ are the resonance frequencies for individual cavities in subsystems $A$ and $B$, respectively, and $k$ is the wave vector. In the left panels, the red and blue curves correspond to the bands for subsystems $A$ and $B$ by themselves, respectively. The cavities in $A$ are coupled to each other via a negative rate. The cavities in $B$ are coupled to each other via a positive rate. The right panels are the band structures ${\omega }_{+}$ and ${\omega }_{-}$ of the coupled system. The figure includes three cases: (a) ${\omega }_A-{\omega }_B\ll -|\beta |$, (b) ${\omega }_A\approx {\omega }_B$, and (c) ${\omega }_A-{\omega }_B\gg |\beta |$.Reuse & Permissions

Figure 3

An implementation of the general system of Fig. 1 in a two-dimensional photonic crystal. The crystal consists of high index ($n=3.4$) rods in a low index material ($n=1.5$) indicated by the gray background. The black dots indicate the dielectric rods. These rods have a radius of $0.2a$, where $a$ is the lattice constant. The blue and red dots represent dielectric rods with a radius of $0.5a$ and with a tunable index near 3.4. These dots form the subsystems $A$ and $B$. The white holes indicate air cylinders with radius $0.2a$.Reuse & Permissions

Figure 4

Propagation of an optical pulse through a coupled microcavity complex in a photonic crystal system as the resonance frequencies of the cavities are varied. The photonic crystal consists of 100 cavity pairs. (a) The dashed and solid black lines represent the variation of resonance frequencies $({\omega }_{A,B}-{\omega }_c)/\beta \equiv \delta \omega /\beta$ as a function of time, respectively. The blue and the red lines represent the electromagnetic intensity as recorded in the middle of subsystems $A$ and $B$, respectively. $t_{\mathrm{p}\mathrm{a}\mathrm{s}\mathrm{s}}$ is the traversal time of the pulse through the system when no index modulation is applied. Open circles are FDTD results, and the red and blue lines are from coupled mode theory. (b) Snapshots of the electric field distributions in the photonic crystal at $t=0.8t_{\mathrm{p}\mathrm{a}\mathrm{s}\mathrm{s}}$ and $t=1.2t_{\mathrm{p}\mathrm{a}\mathrm{s}\mathrm{s}}$, in the upper and lower panels, respectively. The dimensions of the images along the propagation direction are compressed. Yellow represents large positive electric fields. The same color scale is used for both panels. The arrows indicate the propagation direction of the pulse, and the dashed lines represent the locations halfway in between subsystems $A$ and $B$.Reuse & Permissions