By combining photonic crystal resonances with dynamics, we show that photonic crystals can be used to stop, store and time-reverse light pulses. (1 page)
In this paper we review our recent works in developing photonic crystals and nanophotonic structures for the control of light. We show that dynamic crystal structures, in which the refractive index of the material is modulated by a small extent while a photon pulse is in the crystal, can be used to stop, store and even time-reverse light pulses [ 1][ 2][ 3]. We also show that by incorporating magneto-optical effects into the crystal structures, the reciprocity of light can be broken, resulting in uni-directional devices that are extremely compact [ 4]. And finally, by exploiting sub-wavelength electromagnetic resonances in meta structures, new meta-materials can be created. These materials feature frequency-independent refractive index that is controlled by geometry and can be arbitrarily large [ 5]. Such materials can be of importance for integrated optics and image sensing applications.
We discuss how dynamic light stopping and pulse time reversal can be implemented in dispersive waveguides via indirect photonic transitions induced by moving refractive index fronts. The previous concepts of light stopping/time reversal either require complex local variation of the device’s refractive index or rely on the strict phase matching condition, which imposes limitations on the amount of manipulated information. Until now, only single pulses or continuous waves were manipulated experimentally. Our scheme is not limited by a strict phase matching condition and does not require local index variations, thus it can manipulate broadband signals in a single step process. Here, we present several numerically integrated results for pulse time reversal and stopping/storage via indirect front-induced transitions. The presented results are experimentally feasible using existing photonic waveguide technologies.
It is theoretically shown that storage and time reversal of light pulses can be achieved in a coupled-resonator optical waveguide by dynamic tuning of the cavity resonances without maintaining the translational invariance of the system. The control exploits the Bloch oscillation motion of a light pulse in the presence of a refractive index ramp, and it is therefore rather different from the mechanism of adiabatic band compression and reversal proposed by Yanik and Fan in recent works [Phys. Rev. Lett., 92, 083901 (2004); 93, 173903 (2004)].