Molding the light emission and propagation using photonic band gap structures

Controlling and manipulating the spontaneous emission of light sources embedded in nanophotonic structures is a contemporary topic of research due its potential applications in photonics. Photonic band gap structures constitute a class of nanophotonic structure characterized with a periodically altered refractive index along three orthogonal directions. They exhibit photonic stop gaps or even band gap for light wherein the photon density of states vanishes for a range of frequencies irrespective of the directions and polarizations of the incident light.

In this talk, we discuss the experimental studies of tunable photonic stop gaps in three-dimensionally ordered photonic crystals in the visible and near-infrared wavelength ranges. Laser-induced emission studies indicate the modification of spontaneous emission of embedded dyes in photonic crystals. An inhibition of ~51% in emission intensity is observed within the photonic stop gap. At higher excitation energy, strong band-edge-induced lasing characteristics are achieved. Further, we also discuss some interesting aspects of light propagation in two- and three-dimensional silicon photonic crystals.