Photonic crystal

About: Photonic crystal is a research topic. Over the lifetime, 43424 publications have been published within this topic receiving 887083 citations.

High Extraction Efficiency of Spontaneous Emission from Slabs of Photonic Crystals

Abstract: A thin slab of two-dimensional photonic crystal is shown to alter drastically the radiation pattern of spontaneous emission. More specifically, by eliminating all guided modes at the transition frequencies, spontaneous emission can be coupled entirely to free space modes, resulting in a greatly enhanced extraction efficiency. Such structures might provide a solution to the long-standing problem of poor light extraction from high refractive-index semiconductors in light-emitting diodes.

Electromagnetic waves: Negative refraction by photonic crystals.

Abstract: Materials that can bend light in the opposite direction to normal ('left-handed' materials) reverse the way in which refraction usually works — this negative refractive index is due to simultaneously negative permeability and permittivity1,2,3. Here we demonstrate negative refraction of electromagnetic waves in a two-dimensional dielectric photonic crystal that has a periodically modulated positive permittivity and a permeability of unity4,5,6. This experimental verification of negative refraction is a step towards the realization of a 'superlens' that will be able to focus features smaller than the wavelength of light.

Linear waveguides in photonic-crystal slabs

Abstract: Linear waveguides in photonic-crystal slabs, two-dimensionally periodic dielectric structures of finite height, are fundamentally different from waveguides in two-dimensional photonic crystals. The most important distinctions arise from the fact that photonic-crystal slab waveguides must be index-confined in the vertical direction ~while a band gap confines them horizontally!. We present a systematic analysis of different families of waveguides in photonic-crystal slabs, and illustrate the considerations that must be applied to achieve single-mode guided bands in these systems. In this way, the unusual features of photonic-crystal waveguides can be realized in three dimensions without the fabrication complexity required by photonic crystals with complete three-dimensional band gaps.

Ultrafast photonic crystal nanocavity laser

Abstract: Spontaneous emission is not inherent to an emitter, but rather depends on its electromagnetic environment. In a microcavity, the spontaneous emission rate can be greatly enhanced compared with that in free space. This so-called Purcell effect can dramatically increase laser modulation speeds, although to date no time-domain measurements have demonstrated this. Here we show extremely fast photonic crystal nanocavity lasers with response times as short as a few picoseconds resulting from 75-fold spontaneous emission rate enhancement in the cavity. We demonstrate direct modulation speeds far exceeding 100 GHz (limited by the detector response time), already more than an order of magnitude above the fastest semiconductor lasers. Such ultrafast, efficient, and compact lasers show great promise for applications in high-speed communications, information processing, and on-chip optical interconnects.

Nonreciprocal Light Propagation in a Silicon Photonic Circuit

Abstract: Optical communications and computing require on-chip nonreciprocal light propagation to isolate and stabilize different chip-scale optical components. We have designed and fabricated a metallic-silicon waveguide system in which the optical potential is modulated along the length of the waveguide such that nonreciprocal light propagation is obtained on a silicon photonic chip. Nonreciprocal light transport and one-way photonic mode conversion are demonstrated at the wavelength of 1.55 micrometers in both simulations and experiments. Our system is compatible with conventional complementary metal-oxide-semiconductor processing, providing a way to chip-scale optical isolators for optical communications and computing.