Photonic Crystals—A Step towards Integrated Circuits for Photonics

Abstract

The field of photonic crystals has, over the past few years, received dramatically increased attention. Photonic crystals are artificially engineered structures that exhibit a periodic variation in one, two, or three dimensions of the dielectric constant, with a period of the order of the pertinent light wavelength. Such structures in three dimensions should exhibit properties similar to solid-state electronic crystals, such as bandgaps, in other words wavelength regions where light cannot propagate in any direction. By introducing defects into the periodic arrangement, the photonic crystals exhibit properties analogous to those of solid-state crystals. The basic feature of a photonic bandgap was indeed experimentally demonstrated in the beginning of the 1990s, and sparked a large interest in, and in many ways revitalized, photonics research. There are several reasons for this attention. One is that photonic crystals, in their own right, offer a proliferation of challenging research tasks, involving a multitude of disciplines, such as electromagnetic theory, nanofabrication, semi-conductor technology, materials science, biotechnology, to name a few. Another reason is given by the somewhat more down-to-earth expectations that photonics crystals will create unique opportunities for novel devices and applications, and contribute to solving some of the issues that have plagued photonics such as large physical sizes, comparatively low functionality, and high costs. Herein, we will treat some basics of photonic crystal structures and discuss the state-of-the-art in fabrication as well give some examples of devices with unique properties, due to the use of photonic crystals. We will also point out some of the problems that still remain to be solved, and give a view on where photonic crystals currently stand.

Incorporation of Point Defects into Self‐Assembled Three‐Dimensional Colloidal Crystals

“…[26] Photonic crystals (PCs) or photonic bandgap (PBG) materials offer a promising platform for future photonic integrated circuits (PICs) and optoelectronic integrated circuits (OEICs). [1][2][3] Three-dimensional (3D) PCs with a full PBG allow one to control the flow of light omnidirectionally. Currently, there are mainly two methods for fabricating 3D PCs, i.e., "top-down" lithography and "bottom-up" self assembly.…”

Silicon photonic crystal nanostructures for refractive index sensing

“…Silicon photonic crystals ͑PhCs͒ have received great attention over recent years due to the strong potential they provide for applications in the fields of integrated optics 1,2 and optical sensing. [3][4][5] Nanoscale optical cavities formed by introducing point defects into two dimensional PhCs are particularly interesting since they typically support highly localized cavity modes.…”

Colloidal crystallization on tilted substrates under gravitational fields

“…Although such a large-scale 3D PIC has not yet been realized at this stage, small-scale PICs on several semiconductors have already been produced by laser micro-fabrication processes [3][4], and laser micro-fabrication techniques of optical waveguides in close-packed colloidal crystals have also been developed [5][6]. In particular, Taton et al…”