Dynamic group velocity control in a mechanically tunable photonic-crystal coupled-resonator optical waveguide

Abstract

We describe a tunable slow light device based on a photonic-crystal with a mechanically adjustable coupledresonator optical waveguide structure. The lateral energy confinement is implemented along a lattice shear defect with the group velocity actively controlled by shifting the shear along the defect interface over a distance of one crystal period. The group velocity tuning range can be anywhere from arbitrarily small ͑determined by the waveguide structure͒ to near the value expected in bulk media. We present the theory and a demonstration ͑via simulation͒ of a device configuration that is realistic to fabricate and achieves a tunable range of group velocity spanning at least three orders of magnitude. The conditions for stopping the light are also discussed for different configurations.

Cloaks, editors, and bubbles: applications of spacetime transformation theory

“…Also, when thinking of how to modulate wave speeds, as we need to for these spacetime cloaks, we might consider using a group velocity modulation (see e.g. [26,27]), rather than the phase velocity modulation used here. In fact, it is possible to do cloaking in this way, but since a group velocity is in essence a pulse velocity, such a 'group velocity' cloak would work only for illumination consisting of a train of pulses, and not a constant incident wave field.…”

“…This would require a time-dependent (i.e. dynamic) group velocity control [26,27], where a much larger than normal gap between previously regularly spaced pulses is used to construct the cloaking region, before the process is (as usual) reversed to return the illuminating pulse train back to its original state. If such a pulse train was being used as a clock signal to control the behaviour of some signal processing unit (SPU), then this would be the starting point for a interruptwithout-interrupt functionality as proposed by McCall et al [1]; and as outlined in Fig.…”

Exploring Hybrid States and Their Ultrafast Dynamics in Exciton–Plasmon Strong Coupling Systems

“…Therefore, methods involving the use of optical resonators to control the group velocity of light have been employed. 5 Plasmon resonance becomes the ultimate nanoscale optical resonator by converting light into collective oscillations of conduction electrons, 6,7 thereby significantly amplifying the interaction between light and matter. 8−10 It has been employed for a long time in techniques such as surfaceenhanced Raman scattering and high-efficiency higher order harmonic generations.…”

Alternative expression of the Bloch wave group velocity in loss-less periodic media using the electromagnetic field energy

“…The alternative expression of the Bloch wave group velocity is expected to be useful in research topics where the control of light wave group velocity matters, such as in applications related to so-called slow light (8,9). In photocatalysis, for instance, inverse-opal-type 3D photonic crystals are developed (10) in order to enhance solar light absorption, hence photocatalytic activity, through the increase of the photon lifetime (decrease of group velocity) at frequencies located at the edges of the photonic band gap (11).…”