IRG-I Nugget
Defects are perfect when it comes to processing information with light
Scanning Transmission Microscope images of a new photonic crystal structure made of silicon that contains a microcavity device within its interior. Top view (background and foreground-left) and side-view (foreground right). |
In the past 50 years electron semiconductor technology has come to play a vital role in almost every aspect of our daily lives. In the next 50 years our technology might be just as thoroughly revolutionized by also including light (or photons) as a carrier of information in micro devices and components. The key in achieving this advancement is the exploration and development of an exciting new class of materials, called photonic crystals. Photonic crystals allow unprecedented control of confinement and propagation of light, at dimensions of the order of the wavelength itself, thereby enabling the design and eventual integration of a large number and variety of optical micro devices on a single chip. Although many different types of photonic crystals have been described in the literature, the deliberate engineering of defects in these materials, a development needed for actual devices, has been difficult to accomplish in a 3D photonic crystal. Recently, MIT MRSEC professors Joannopoulos, Ippen, and Smith succeeded in the first fabrication and characterization of a photonic crystal at optical lengthscales that contains a deliberately designed point defect that can act as a microcavity (Qi et al., Nature 429, 538-542, 2004). A top and side-view of the fabricated structure is shown in the figure below. This structure is the first important step towards large-scale optical integration and the realization of very large information carrying ability and high efficiency devices.
