Photonic crystals are nanostructured materials with periodic modulation of dielectric constant in up to three dimensions. When designed properly, they exhibit a photonic band gap - a range of energies that photons propagating through them cannot occupy. These materials are important and interesting because they can be used to manipulate photons in a way similar to control of electrons in semiconductor circuits (and for this reason, they are often referred to as "semiconductors for light"). For example, by introducing defects and dislocations into photonic crystal lattices, one can build tiny waveguides that guide light and bend it at sharp angles, or construct microcavities that localize photons into extremely small volumes, even smaller than a cubic optical wavelength. A variety of miniaturized optical devices can thus be constructed and integrated with high density on a photonic crystal chip, including light sources, waveguides, filters, and modulators. On the other hand, the ability to localize light into very small volumes and with high quality factors in photonic crystal microcavities enables us to study cavity quantum electrodynamics (QED) phenomena in the solid state, as well as to build novel quantum optical devices, such as efficient single- or entangled-photon sources.
Our research spans a number of experimental and theoretical topics in micro- and nano-scale photonics and quantum optics, ranging from applications of photonic crystals in miniaturization and integration of optical components, to solid-state photonic quantum information technologies.