The year marks the silver jubilee of Photonic Crystals. The photonic crystals has transformed science and technology by developing new areas which lies at the boundary of condensed matter physics and photonics. Areas such as meta-materials, have been born out of this synergy, striking out in new directions and flourishing in their own right. Last twenty five years has seen numerous of improvements in this area.
The credit goes to two key people Eli Yablonovitch (Bell Labs) and Sajeev John (Princeton University), who tried to address the simple problems of rigorous suppression of spontaneous emission of excited atoms inside a dielectric cavities and the observing Anderson Localization (absence of wave transport in disordered medium) using classical electromagnetic waves in non-dissipative systems, respectively. Interestingly, the solution they both proposed was to design a three dimensional periodic dielectric structure (spatial periodic) in which the complete electromagnetic bandgap opens up in the photon dispersion relation.
The initial work by both of them was theoretical in nature and remained unnoticed for a few years until some initial attempts were made to develop a three-dimensional photonic bandgaps. At this the time the community in this area became aware of the implications and the true potential of this concept. This resulted in a good amount of activity and interesting tangible output.
Some of the commercially available applications include ultra-broadband, high-brightness spectra via super-continuum generation in photonic crystal fibers light coupling to silicon photonic chips, enhanced light extraction from light-emitting diodes and laser-light guiding for cancer surgery.
Furthermore, it has been recognized that periodic nano-structures are abundant in the animal world, where they are responsible for the bright, iridescent colors (particularly blue) found on the skin, wings or feathers of tropical fishes, hummingbirds, moths, beetles, butterflies and peacocks, among other species.
The realization of truly three dimensional photonic crystals, particularly at optical wavelengths, has proved persistently challenging owing to the intricacy of periodically nano-sculpturing a material in all three spatial dimensions. This is a limit at this moment at the technological impact of these structures. With continuous advances in the synthesis, fabrication and self-assembly of photonic nano-materials it is thought that these challenges will eventually be overcomed.
Extracted from Early Lights in Nature Materials |11|95|(2012)| doi:10.1038/nmat3519|Published online on 23 November 2012