17 research outputs found
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
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
Tamm plasmon Photonic Crystals : from Bandgap Engineering to Defect Cavity
We report for the first time the bandgap engineering of Tamm plasmon photonic
crystals - Tamm plasmon structures of which the metalic layer is periodically
patterned into lattice of subwavelength period. By adopting a double period
design, we evidenced experimentally a complete photonic bandgap up to
in the telecom range. Moreover, such design offers a great flexibility to
tailor on-demand, and independently, the band-gap size from to
and its spectral position within . Finally, by implementing a
defect cavity within the Tamm plasmon photonic crystal, an ultimate cavity of
supporting a single highly confined Tamm mode is experimentally
demonstrated. All experimental results are in perfect agreement with numerical
calculations. Our results suggests the possibility to engineer novel band
dispersion with surface modes of hybrid metalic/dielectric structures, thus
open the way to Tamm plasmon towards applications in topological photonics,
metamaterials and parity symmetry physics
Taming Friedrich-Wintgen interference in resonant metasurface: vortex laser emitting at on-demand tilted-angle
Friedrich-Wintgen (FW) interference is an atypical coupling mechanism that
grants loss exchange between leaky resonances in non-Hermitian classical and
quantum systems. Intriguingly, such an mechanism makes it possible for
destructive interference scenario in which a radiating wave becomes a bound
state in the continuum (BIC) by giving away all of its losses. Here we propose
and demonstrate experimentally an original concept to tailor FW-BICs as
polarization singularity at on-demand wavevectors in optical metasurface. As a
proof-of-concept, using hybrid organic-inorganic halide perovskite as active
material, we empower this novel polarization singularity to obtain lasing
emission exhibiting both highly directional emission at oblique angles and
polarization vortex in momentum space. Our results pave the way to steerable
coherent emission with tailored polarization pattern for applications in
optical communication/manipulation in free-space, high-resolution imaging
/focusing and data storage
Strong Coupling between Plasmons and Organic Semiconductors
In this paper we describe the properties of organic material in strong coupling with plasmon, mainly based on our work in this field of research. The strong coupling modifies the optical transitions of the structure, and occurs when the interaction between molecules and plasmon prevails on the damping of the system. We describe the dispersion relation of different plasmonic systems, delocalized and localized plasmon, coupled to aggregated dyes and the typical properties of these systems in strong coupling. The modification of the dye emission is also studied. In the second part, the effect of the microscopic structure of the organics, which can be seen as a disordered film, is described. As the different molecules couple to the same plasmon mode, an extended coherent state on several microns is observed
Strong Coupling between Plasmons and Organic Semiconductors
In this paper we describe the properties of organic material in strong coupling with plasmon, mainly based on our work in this field of research. The strong coupling modifies the optical transitions of the structure, and occurs when the interaction between molecules and plasmon prevails on the damping of the system. We describe the dispersion relation of different plasmonic systems, delocalized and localized plasmon, coupled to aggregated dyes and the typical properties of these systems in strong coupling. The modification of the dye emission is also studied. In the second part, the effect of the microscopic structure of the organics, which can be seen as a disordered film, is described. As the different molecules couple to the same plasmon mode, an extended coherent state on several microns is observed
Active control of radiation beaming from Tamm nanostructures by optical microscopy
International audienceActive control of the radiation orientation (beaming) of a metallic antenna has been reported by various methods, where the antenna excitation position was tuned with a typical 50 nm precision by a near-field tip or an electron-beam. Here we use optical microscopy to excite and analyze the fluorescence of a layer of nanocrystals embedded in an optical Tamm state nanostructure (metallic disk on top of a Bragg mirror). We show that the radiation pattern can be controlled by changing the excitation spot on the disk with only micrometer precision, in a manner which can be well described by numerical simulations. A simplified analytical model suggests that the propagation length of the in-plane confined optical modes is a key parameter for beaming control
Manifestation of Planar and Bulk Chirality Mixture in Plasmonic Λ‑Shaped Nanostructures Caused by Symmetry Breaking Defects
We
report on the coexistence of planar and bulk chiral effects
in plasmonic Λ-shaped nanostructure arrays arising from symmetry
breaking defects. The manifestation of bi- (2D) and three-dimensional
(3D) chiral effects are revealed by means of polarization tomography
and confirmed by symmetry considerations of the experimental Jones
matrix. Notably, investigating the antisymmetric and symmetric parts
of the Jones matrix points out the contribution of 2D and 3D chirality
in the polarization conversion induced by the system whose eigenpolarizations
attest to the coexistence of planar and bulk chirality. Furthermore,
we introduce a generalization of the microscopic model of Kuhn, yielding
to a physical picture of the origins of the observed planar chirality,
circular birefringence, and dichroism, theoretically prohibited in
symmetric Λ-shaped nanostructures