ABSTRACT
Quantum emitters such as NV-centers or quantum dots can be used as single-photon sources. To improve their performance, they can be coupled to microcavities or nano-antennas. Plasmonic antennas offer an appealing solution as they can be used with broadband emitters. When properly designed, these antennas funnel light into useful modes, increasing the emission rate and the collection of single-photons. Yet, their inherent metallic losses are responsible for very low radiative efficiencies. Here, we introduce a new design of directional, metallo-dielectric, optical antennas with a Purcell factor of 150, a total efficiency of 74% and a collection efficiency of emitted photons of 99%.
ABSTRACT
We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna consists of a thin gold microdisk separated from a planar gold layer by a few tens of nanometers thick dielectric layer. The emitters are shown to radiate through the entire patch antenna in a highly directional and vertical radiation pattern. Strong acceleration of spontaneous emission is observed, depending on the antenna geometry. Considering the double dipole structure of the emitters, this corresponds to a Purcell factor up to 80 for dipoles perpendicular to the disk.
Subject(s)
Colloids/chemistry , Gold/chemistry , Quantum Dots , Equipment Design , Light , Nanostructures/chemistry , Nanotechnology , Optics and Photonics , Surface Plasmon ResonanceABSTRACT
The electromagnetic modes of a GaAs quantum well between two AlGaAs barriers are studied. At the longitudinal optical phonon frequency, the system supports a phonon polariton mode confined in the thickness of the quantum well that we call epsilon-near-zero mode. This epsilon-near-zero mode can be resonantly excited through a grating resulting in a very large absorption localized in the single quantum well. We show that the reflectivity can be modulated by applying a voltage. This paves the way to a new class of active optoelectronic devices working in the midinfrared and far infrared at ambient temperature.
ABSTRACT
We present an explicit form of the surface plasmon propagator. Its form has the structure of a vectorial Huygens-Fresnel principle. The propagator appears to be a powerful tool to deal with diffraction, interference and focusing of surface plasmons. In contrast with the scalar approximation used so far, the vectorial propagator accounts for near-field and polarization effects. We illustrate the potential of the propagator by studying diffraction of surface plasmons by a slit and focusing of surface plasmons by a Fresnel lens.
Subject(s)
Light , Models, Theoretical , Refractometry/methods , Surface Plasmon Resonance/methods , Computer Simulation , Scattering, RadiationABSTRACT
Absorption and emission of light due to the resonant excitation of surface waves on a grating is a well-known phenomenon. We report the first complete study of the influence of the role of angle and polarization on thermal emission by lamellar gratings. We derive the emitted Stokes vectors in any direction. We find that a source can be quasi isotropic from the point of view of the intensity but strongly anisotropic for polarized light. It follows that the degree of polarization can vary between 0 and 1, depending on directions.
Subject(s)
Computer-Aided Design , Models, Theoretical , Refractometry/instrumentation , Refractometry/methods , Computer Simulation , Equipment Design , Equipment Failure Analysis , Light , Scattering, Radiation , TemperatureABSTRACT
We report the design of a tungsten thermal source with extraordinarily high directivity in the near infrared, comparable to the directivity of a CO2 laser. This high directivity is the signature of the long-range correlation of the electromagnetic field in the source plane. This phenomenon is due to the resonant thermal excitation of surface-plasmon polaritons.
ABSTRACT
Enhanced transmission and absorption by a silver film with a periodic array of slits has been studied numerically. We find that transmission and absorption peaks coincide and can be attributed to resonances of the structure. We show that these modes can be viewed as a coupling between cavity modes and surface plasmon polaritons. A quantitative analysis shows that the coupled mode can have a cavity mode character or a surface plasmon character depending on the distance to the crossing point of their dispersion relation. Finally, we provide a simple model for the peak transmission value by introducing the concept of radiative yield.
ABSTRACT
Resonant transmission through metallic films is observed when a periodic array of holes is drilled. This phenomenon has been attributed to surface plasmon polaritons. We study a similar system made of an array of slits in a SiC film supporting surface phonon polaritons. We find a resonant transmission in the infrared. The role of surface waves is analyzed. We find that surface waves are excited at resonance but are not a necessary condition to obtain a resonant transmission.
