199 research outputs found
Spatio-temporal second-order quantum correlations of surface plasmon polaritons
We present an experimental methodology to observe spatio-temporal
second-order quantum coherence of surface plasmon polaritons which are emitted
by nitrogen vacancy color centers attached at the apex of an optical tip. The
approach relies on leakage radiation microscopy in the Fourier space and we use
this approach to test wave-particle duality for surface plasmon polaritons
Surface Plasmon Polariton microscope with Parabolic Reflectors
We report the realization of a two--dimensional optical microscope for
surface plasmons polaritons (SPPs) based on parabolic Bragg mirrors. These
mirrors are built from lithographically fabricated gold nanostructures on gold
thin films. We show by direct imaging by leakage radiation microscopy that the
magnification power of the SPP microscope follows basic predictions of
geometrical optics. Spatial resolution down to the value set by the diffraction
limit is demonstrated.Comment: Opt.Lett.32, 2414 (2007
Plasmonic Demultiplexer and Guiding
Two-dimensional plasmonic demultiplexers for surface plasmon polaritons
(SPPs), which consist of concentric grooves on a gold film, are proposed and
experimentally demonstrated to realize light-SPP coupling, effective dispersion
and multiple-channel SPP guiding. A resolution as high as 10 nm is obtained.
The leakage radiation microscopy imaging shows that the SPPs of different
wavelengths are focused and routed into different SPP strip waveguides. The
plasmonic demultiplexer can thus serve as a wavelength division multiplexing
element for integrated plasmonic circuit and also as a plasmonic spectroscopy
or filter.Comment: 17 pages, 5 figure
Dielectric nanoantenna as an efficient and ultracompact demultiplexer for surface waves
Nanoantennas for highly efficient excitation and manipulation of surface
waves at nanoscale are key elements of compact photonic circuits. However,
previously implemented designs employ plasmonic nanoantennas with high Ohmic
losses, relatively low spectral resolution, and complicated lithographically
made architectures. Here we propose an ultracompact and simple dielectric
nanoantenna (silicon nanosphere) allowing for both directional launching of
surface plasmon polaritons on a thin gold film and their demultiplexing with a
high spectral resolution. We show experimentally that mutual interference of
magnetic and electric dipole moments supported by the dielectric nanoantenna
results in opposite propagation of the excited surface waves whose wavelengths
differ by less than 50 nm in the optical range. Broadband reconfigurability of
the nanoantennas operational range is achieved simply by varying the diameter
of the silicon sphere. Moreover, despite subwavelength size () of
the proposed nanoantennas, they demonstrate highly efficient and directional
launching of surface waves both in the forward and backward directions with the
measured front-to-back ratio having a contrast of almost two orders of
magnitude within a 50 nm spectral band. Our lithography-free design has great
potential as highly efficient, low-cost, and ultracompact demultiplexer for
advanced photonic circuits.Comment: added relevant references; fixed typos in Supplementary eq. 8,9,1
Photonic bandgap plasmonic waveguides
A novel type of a plasmonic waveguide has been proposed featuring an "open"
design that is easy to manufacture, simple to excite and that offers a
convenient access to a plasmonic mode. Optical properties of photonic bandgap
(PBG) plasmonic waveguides are investigated experimentally by leakage radiation
microscopy and numerically using the finite element method confirming photonic
bandgap guidance in a broad spectral range. Propagation and localization
characteristics of a PBG plasmonic waveguide have been discussed as a function
of the wavelength of operation, waveguide core size and the number of ridges in
the periodic reflector for fundamental and higher order plasmonic modes of the
waveguide
Quantum plasmonics: second-order coherence of surface plasmons launched by quantum emitters into a metallic film
We address the issue of the second-order coherence of single surface plasmons
launched by a quantum source of light into extended gold films. The quantum
source of light is made of a scanning fluorescent nanodiamond hosting five
nitrogen-vacancy (NV) color centers. By using a specially designed microscopy
that combines near-field optics with far-field leakage-radiation microscopy in
the Fourier space and adapted spatial filtering, we find that the quantum
statistics of the initial source of light is preserved after conversion to
surface plasmons and propagation along the polycrystalline gold film.Comment: Second version with minor changes made to comply with Referees'
comments. Editorially approved for publication in Phys. Rev. B on 22 June
201
Directional and singular surface plasmon generation in chiral and achiral nanostructures demonstrated by Leakage Radiation Microscopy
In this paper, we describe the implementation of leakage radiation microscopy
(LRM) to probe the chirality of plasmonic nanostructures. We demonstrate
experimentally spin-driven directional coupling as well as vortex generation of
surface plasmon polaritons (SPPs) by nanostructures built with T-shaped and
- shaped apertures. Using this far-field method, quantitative
inspections, including directivity and extinction ratio measurements, are
achieved via polarization analysis in both image and Fourier planes. To support
our experimental findings, we develop an analytical model based on a
multidipolar representation of - and T-shaped aperture plasmonic
coupler allowing a theoretical explanation of both directionality and singular
SPP formation. Furthermore, the roles of symmetry breaking and phases are
emphasized in this work. This quantitative characterization of spin-orbit
interactions paves the way for developing new directional couplers for
subwavelength routing
Highly efficient singular surface plasmon generation by achiral apertures
We report a highly efficient generation of singular surface plasmon (SP)
field by an achiral plasmonic structure consisting of -shaped
apertures. Our quantitative analysis based on leakage radiation microscopy
(LRM) demonstrates that the induced spin-orbit coupling can be tuned by
adjusting the apex angle of the -shaped aperture. Specifically, the
array of -shaped apertures with the apex angle is shown to
give rise to the directional coupling efficiency. The ring of -shaped
apertures with the apex angle realized to generate the maximum
extinction ratio (ER=11) for the SP singularities between two different
polarization states. This result provides a more efficient way for developing
SP focusing and SP vortex in the field of nanophotonics such as optical
tweezers
Defocus leakage radiation microscopy for single shot surface plasmon measurement
Measurement of surface plasmon and surface wave propagation is important for the operation and characterization of sensors and microscope systems. One challenge is to perform these measurements both quickly and with good spatial resolution without any modification to the sample surface. This paper addresses these issues by projecting an image of the field excited from a defocused sample to a magnified image plane. By carefully analysing the intensity distribution in this plane the properties of the surface waves generated on the sample surface can be determined. This has the advantage over previous techniques that the data can be obtained in a single shot without any changes to the focal position of the sample. Equally importantly, we show the method measures the local properties of the sample at well-defined positions, whereas other methods such as direct observation of the back focal plane average the properties over the propagation length of the surface waves
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