Single Photon Emitters Coupled to Plasmonic Waveguides: A Review

Abstract

During the last two decades, many research groups have demonstrated coupling of single photon emitters to plasmonic waveguides, promising very high emission enhancements, for applications in quantum technologies. In this review, recent developments within this important research topic are discussed. Different plasmonic waveguide-quantum emitter configurations are compared from the application viewpoint by utilizing a figure-of-merit (FOM) reflecting the emission enhancement, coupling efficiency, and radiation loss. The experimental methods applied to obtain the coupled systems with high FOMs are described. Configurations that are exploited for reinforcing the coupling efficiency, i.e., the efficiency of funneling the emitted radiation into a plasmonic waveguide, are also considered as well as the scalability potential of various waveguide platforms. A recent experiment, in which enhanced light-matter interaction in a plasmonic waveguide is taken advantage of, resulting in the demonstration of non-linearity at the single emitter level, is discussed.

Efficient Spin‐Direction Coupling between Circular Polarized Electric and Magnetic Dipoles and Photonic Modes

“…[ 12 ] Moreover, plasmonic waveguides have also been employed for the enhancement of the emission of quantum emitters in quantum technologies. [ 13 ] However, all these integrated photonic structures were developed following physical insights and designer's intuition, dealing with predefined configurations. As the quantum integrated circuits scale up to large bandwidth, multifrequency applications, nonlinear phenomena, and dense integration, the prototypical approach poses a challenge of increasing complexity.…”

Plexcitonic Quantum Light Emission from Nanoparticle-on-Mirror Cavities

“… 15 Devices based on guiding geometries decorated with in- and out-coupling elements have been thoroughly investigated. 16 , 17 SPs suffer heavily from metallic absorption in these extended systems. For this reason, nanocavities have emerged as an alternative for nonclassical light sources of smaller dimensions.…”

“…The quest for plasmon-assisted generation of radiative quantum states of light, propagating in free-space and into the far-field, has attracted much attention lately . Devices based on guiding geometries decorated with in- and out-coupling elements have been thoroughly investigated. , SPs suffer heavily from metallic absorption in these extended systems. For this reason, nanocavities have emerged as an alternative for nonclassical light sources of smaller dimensions.…”

Simultaneous Nanoscale Excitation and Emission Mapping by Cathodoluminescence

“…In particular, a most interesting piece of information in CL lies is the processes taking place in between excitation and emission, producing spatiotemporal energy flow across different modes of the specimen. Indeed, the excitation and emission positions do not match in general in optical systems such as semiconductors due to carrier diffusion, topologically protected edge-states capable of transporting electromagnetic energy before out-coupling to radiation, cavities combined with localized emitters, and many others. ,, Although the CL approach is advantageous with respect to EELS for the characterization of emission, it does not directly reveal the position from which photons are emerging. This leaves us with a longstanding problem in the analysis of semiconductor optical devices, where excited carriers or excitons recombine and emit photons (incoherent emission processes) after some spatial diffusion that reduces the effective spatial resolution in the CL measurement. , Also, in nanophotonic antennas or waveguides dominated by coherent processes, the determination of the emission position is important to analyze and engineer electromagnetic energy transport and conversion .…”

“…Indeed, the excitation and emission positions do not match in general in optical systems such as semiconductors due to carrier diffusion, topologically protected edge-states capable of transporting electromagnetic energy before out-coupling to radiation, cavities combined with localized emitters, and many others. 6,9,10 Although the CL approach is advantageous with respect to EELS for the characterization of emission, it does not directly reveal the position from which photons are emerging. This leaves us with a longstanding problem in the analysis of semiconductor optical devices, where excited carriers or excitons recombine and emit photons (incoherent emission processes) after some spatial diffusion that reduces the effective spatial resolution in the CL measurement.…”