0000000000005170
AUTHOR
Marlène Petit
Single-Crystal vs Polycrystalline Gold: A Non-linear-Optics Analysis
Standard gold in the field of plasmonics is obtained by evaporation or sputtering and therefore is polycrystalline. Yet, this gold presents numbers of drawbacks such as roughness, grains and ill-defined electronic band diagrams in addition to the lack of reproducibility from one instrument to another. It is, thus, beneficial to turn to a metal production that can enable well-defined and controlled gold parameters. To that end, we have explored the wet synthesis of gold nanoplates which represents a simple and robust means of obtaining single-crystal gold (Guo Z, Zhang Y, DuanMu Y, Xu L, Xie S, Gu N, Colloids Surf A 278:33–38, 2006). The synthesized nanoplates are from 50 to less than 100 nm…
Cavity Resonator Integrated Guided mode resonance Filter : Spectral & Modal Reflector
International audience; CRIGF is a new generation of narrowband filter. It consists of subwavelength gratings nearby or upon a waveguide. At the center, a small GMRF (Guided Mode Resonance Filter) or GC (Grating Coupler) coupled radiated & guided mode, then, DBR (Distributed Bragg Reflector) at each side localise mode inside a horizontal Fabry-Pérot cavity. Two PS (Phase sections) are use to fine tune the Fabry-Pérot modes with the grating coupler.
Multimodal reflectivity of CRIGF filters: First experimental observation and modelling
International audience; Cavity Resonator Integrated Guided-mode Resonance Filter (CRIGF) are a new class of filtering reflectors whose selected wavelength and spectral width are independent of the angle of incidence unlike GMRF. These particular properties allow both compactness and a high angular acceptance. However, ours studies show that CRIGFs offer simultaneously spectral and modal filtering and we evidence high-spatial-order reflected modes. In this paper, we will present characterization of the spectral and spatial profile that demonstrates the existence of these high-order modes. In addition, we will present a model based on the physical understanding of implied phenomena to explain…
High Order modes in Cavity Resonator Integrated Guided mode resonance Filters (CRIGFs)
International audience
High-order modes in cavity-resonator-integrated guided-mode resonance filters (CRIGFs)
International audience; Cavity-resonator-integrated guided-mode resonance filters (CRIGFs) are optical filters based on weak coupling by a grating between a free-space propagating optical mode and a guided mode, like guided-mode resonance filters (GMRFs). As compared to GMRFs they offer narrowband reflection with small aperture and high angular acceptance. We report experimental characterization and theoretical modeling of unexpected high-order reflected modes in such devices. Using coupled-mode modeling and moiré analysis we provide physical insight on key mechanisms ruling CRIGF properties. This model could serve as a simple and efficient framework to design new reflectors with tailored s…
2D Waveguided Bessel Beam Generated Using Integrated Metasurface-Based Plasmonic Axicon.
International audience; Near-field imaging of the propagation of a diffraction-free Bessel-type beam in a guided wave configuration generated by means of a metasurface-based axicon lens integrated on a silicon waveguide is reported. The operation of the axicon lens with a footprint as small as 11 μm2 is based on local engineering of the effective index of the silicon waveguide with plasmonic nanoresonators. This generic approach, which can be adapted to different types of planar lightwave circuit platforms, offers the possibility to design nano-engineered optical devicesbased on the use of plasmonic resonators to control light at the nanoscale.
Selective excitation of bright and dark plasmonic resonances of single gold nanorods.
Plasmonic dark modes are pure near-field resonances since their dipole moments are vanishing in far field. These modes are particularly interesting to enhance nonlinear light-matter interaction at the nanometer scale because radiative losses are mitigated therefore increasing the intrinsic lifetime of the resonances. However, the excitation of dark modes by standard far field approaches is generally inefficient because the symmetry of the electromagnetic near-field distribution has a poor overlap with the excitation field. Here, we demonstrate the selective optical excitation of bright and dark plasmonic modes of single gold nanorods by spatial phase-shaping the excitation beam. Using two-p…