Search results for "Physics::Optics"
showing 10 items of 1958 documents
In-fiber time-resolved acousto-optics
2014
Time-resolved in-fiber acousto-optics permit the measurement of sub-ppm perturbations of the modal dispersion curves along sections of fiber exceeding 1 m long, with a spatial resolution in the order of few cm.
Dispersion induced effects of high-order optical sidebands in the performance of millimeter-wave fiber-optic links
2006
In this paper, chirped fiber Bragg gratings (CFBGs) are proposed as signal-phase controllers for microwave-photonic wireless downstream fiber links. The effect of high-order modulation optical sidebands that disturbs the output mm-wave signal due to the chromatic dispersion induced by the gratings is studied theoretically and experimentally. The 1st and 2nd mm-wave harmonics of the output signal have been measured for conventional intensity modulation and for intensity modulation with optical carrier suppression. In the last case, data transmission at 2.5 Gb/s is demonstrated through a chirped grating of 280 ps/nm dispersion in a 40-GHz modulated link.
Extremely efficient evaluation of chromatic dispersion in realistic photonic crystal fibers
2004
We present a fast and accurate procedure for the evaluation of chromatic dispersion in photonic crystal fibers. It combines an iterative Fourier technique to compute the propagation constant at any fixed wavelength and an analytical approach to calculate its derivatives.
Suppression of pulse pedestal using nonlinear optical loop mirrors in grating-compensated dispersion-managed fiber transmission systems
2006
Pulse pedestal suppression by nonlinear optical loop mirrors is utilized to reduce the intersymbol interference caused by the group delay ripples of a real grating profile in dispersion-managed communication systems compensated by chirped fiber gratings.
Strong coupling between surface plasmon polaritons and Sulforhodamine 101 dye
2011
We demonstrate a strong coupling between surface plasmon polaritons and Sulforhodamine 101 dye molecules. Dispersion curves for surface plasmon polaritons on samples with a thin layer of silver covered with Sulforhodamine 101 molecules embedded in SU-8 polymer are obtained experimentally by reflectometry measurements and compared to the dispersion of samples without molecules. Clear Rabi splittings, with energies up to 360 and 190 meV, are observed at the positions of the dye absorption maxima. The split energies are dependent on the number of Sulforhodamine 101 molecules involved in the coupling process. Transfer matrix and coupled oscillator methods are used to model the studied multilaye…
Achromatic Varifocal Metalens for the Visible Spectrum
2019
Metasurface optics provide an ultra-thin alternative to conventional refractive lenses. A present challenge is in realizing metasurfaces that exhibit tunable optical properties and achromatic behavior across the visible spectrum. Here, we report the design, fabrication, and characterization of metasurface lenses ("metalenses") that use asymmetric TiO2 nanostructures to induce a polarization-dependent optical response. By rotating the polarization of linearly-polarized input light, the focal length of a 40 micrometer-diameter metalens is tuned from 220-550 micrometers with nearly diffraction-limited performance. We show that imparting a wavelength-dependent polarization rotation on incident …
Quantitative analysis of localized surface plasmons based on molecular probing
2010
International audience; We report on the quantitative characterization of the plasmonic optical near-field of a single silver nanoparticle. Our approach relies on nanoscale molecular molding of the confined electromagnetic field by photoactivated molecules. We were able to directly image the dipolar profile of the near-field distribution with a resolution better than 10 nm and to quantify the near-field depth and its enhancement factor. A single nanoparticle spectral signature was also assessed. This quantitative characterization constitutes a prerequisite for developing nanophotonic applications.
Dielectric-loaded plasmonic waveguide components: Going practical
2013
Surface plasmon propagating modes supported by metal/dielectric interfaces in various configurations can be used for radiation guiding similarly to conventional dielectric waveguides. Plasmonic waveguides offer two attractive features: subdiffraction mode confinement and the presence of conducting elements at the mode-field maximum. The first feature can be exploited to realize ultrahigh density of nanophotonics components, whereas the second feature enables the development of dynamic components controlling the plasmon propagation with ultralow signals, minimizing heat dissipation in switching elements. While the first feature is yet to be brought close to the domain of practical applicatio…
Dielectric-loaded surface plasmon polariton waveguides: Figures of merit and mode characterization by image and Fourier plane leakage microscopy
2008
International audience; Waveguiding of surface plasmon polaritons by dielectric-loaded metal structures is studied in detail by combining numerical simulations and leakage radiation microscopy. These types of waveguides are first numerically investigated using the effective index model and the differential method. We analyzed systematically the influence of the ridge width and thickness of the waveguide on the properties of the surface plasmon guided modes. In particular we investigated the confinement factor of the modes and their associated propagation lengths. These two parameters can be optimized by adjusting the thickness of the dielectric layer. Waveguides loaded with thick and thin d…
Surface plasmon subwavelength optics.
2003
International audience; Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons- in particular their interaction with light-can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.