Purcell effect

Abstract: We realize a cavity magnon-microwave photon system in which a magnetic dipole interaction mediates strong coupling between the collective motion of a large number of spins in a ferrimagnet and the microwave field in a three-dimensional cavity. By scaling down the cavity size and increasing the number of spins, an ultrastrong coupling regime is achieved with a cooperativity reaching 12 600. Interesting dynamic features including classical Rabi-like oscillation, magnetically induced transparency, and the Purcell effect are demonstrated in this highly versatile platform, highlighting its great potential for coherent information processing.

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.

Abstract: In this Review, the theory and applications of optical micro and nanoresonators are presented from the underlying concept of their natural resonances, the so-called quasi-normal modes (QNMs). The latter are the basic constituents governing the response of resonators. Characterized by complex frequencies, QNMs are initially loaded by a driving field and then decay exponentially in time due to power leakage or absorption. Here, the use of QNM-expansion formalisms to model these basic effects is explored. Such modal expansions that operate at complex frequencies distinguish from the current user habits in electromagnetic modeling, which rely on classical Maxwell equation solvers operating at real frequencies or in the time domain; they also bring much deeper physical insight into the analysis. An extensive overview of the historical background on QNMs in electromagnetism and a detailed discussion of recent relevant theoretical and numerical advances are therefore presented. Additionally, a concise description of the role of QNMs on a number of examples involving electromagnetic resonant fields and matter, including the interaction between quantum emitters and resonators (Purcell effect, weak and strong coupling, superradiance...), Fano interferences, the perturbation of resonance modes, and light transport and localization in disordered media is provided.

Abstract: A strong enhancement of the spontaneous emission rate (Purcell effect) has been observed for self-assembled InAs/GaAs quantum boxes inserted in GaAs-based pillar microcavities (/spl times/5) and microdisks (/spl times/15) using time-resolved as well as c.w. photoluminescence experiments. We show that the magnitude of the Purcell effect can be quantitatively understood by considering both the Purcell figure of merit F/sub p/ of such cavities (F/sub p//spl Gt/1) and the spatial/spectral distribution of the inhomogeneous collection of atom-like emitters. These results open the way to the development of single-photon devices such as photon-guns or photon-turnstiles, able to emit photons one-by-one in a deterministic way.