Reading “Slowing and stopping light using an optomechanical crystal array”

Published on: Tue Jan 11 2011

Slowing and stopping light using an optomechanical crystal array” from the Institute for Quantum Information at Caltech, is about an idea for storing information as light, by slowing the light. (Can light travel slower than the speed of light?) Right now optical networks have to transition to an electrical signal to store information. There are several different schemes already under consideration for how to do this, and the approach taken in this paper combines many of their features.

The scheme used in this paper involves mapping the optical field into mechanical excitations. The mechanical excitations are created on an optomechancial crystal array. Directly quoting the authors an optomechanical crystal is “a periodic structure that constitutes both a photonic and a phononic crystal.” Photonic crystals are composed of patterns regions of high and low dielectric constants. Phononic crystals are patterns of regions of elasticity and mass. Photonic crystals are light based and phononic crystals are sound based.

The optomechanical crystal works by transferring the cavity mode of an optical cavity to the mechanical mode of the crystal. The cavity mode comes from an optical waveguide that is coupled to it. The optical modes leak energy into the waveguide and have a decay rate as well. There is a driving amplitude of Capital omega for a single optical cavity system. A Hamiltonian is used to describe the dynamics of a single element, depending on whether or not the system has one or two optical cavities, the Hamiltonian contains the optomechanical driving amplitude (for single cavity).