Search results for "Photon"
showing 10 items of 3171 documents
SNOM signal near plasmonic nanostructures: an analogy with fluorescence decays channels
2008
International audience; Scanning Near-field Optical Microscope (SNOM) is based on local excitations of nanostructures deposited on a substrate (illumination mode). Ideally, the local source behaves like a dipolar emitter so that the SNOM signal is strongly similar to the fluorescence decay rates of an excited molecule that would be located at the SNOM tip position. We present here how the SNOM signal near plasmonic nanostructures can be used to analyze radiative and non-radiative contribution to the fluorescence decay rate.
Surface plasmon routing in dielectric-loaded surface plasmon polariton waveguides - art. no. 70330S
2008
International audience; Waveguiding by dielectric-loaded surface plasmon-polaritons (DLSPP) structures are numerically and experimentally investigated. We used the effective index model to understand the influence of basic waveguide parameters such as width and thickness on the properties of the surface plasmon guided modes. A waveguide was fabricated and experimentally studied. The effective indices of the modes supported by the waveguide and their propagation length are evaluated by leakage radiation microscopy in both the Fourier and imaging planes. Several excitation schemes were tested including surface plasmon coupling by diascopic or episcopic illumination as well as defect-mediated …
Far-field imaging of the electromagnetic local density of optical states.
2008
International audience; We introduce a new experimental method to measure the local electromagnetic density of states (LDOS) by integrating the differential scattering cross section. The signal detected essentially reflects the intrinsic scattering response of the photonic structures and renders the partial LDOS dominated by evanescent modes. We give a theoretical understanding of the LDOS image formation and show a qualitative agreement between experimental images and theoretical maps. This approach can be practically applied to the direct measurement of an optical antenna's scattering efficiency and can provide valuable information for designing optimum structures utilized in radiative de…
Sub-nanosecond nonlinear pulse shaping in microfiber resonators
2009
Thanks to their small size and large index contrast allowing for tight field confinement, optical microfibers are of great interest in nonlinear optics. Their properties have recently been exploited in various devices for supercontinuum generation, pulse compression [1] and third-harmonic generation [2]. Combining field confinement and field enhancement in a loop or knot resonator can result in low-threshold non-linear microfibre devices, in which pulse shaping effects and bistability can be obtained. Such a behaviour has already been observed at a power level of ten milliwatts with millisecond time response, in the case of thermally-induced non-linearity in silica microfibres [3]. In contr…
Real time measurement of long parabolic optical similaritons
2008
International audience; Long optical similaritons using a Raman fibre amplifier are generated. These pulses, with a highly parabolic profile, are monitored in real time on a high speed oscilloscope. Tunability of both the temporal and spectral widths of the pulses is then investigated.
Mid-infrared strong spectral broadening in microstructured tapered chalcogenide AsSe fiber
2012
We report on the generation of a supercontinuum in a chalcogenide microstructured tapered fiber. The suspended core diameter of the fiber is reduced from 5.5 μm to 0.8 μm in the waist of the tapered region. The zero dispersion wavelength is below 2 μm in the tapered region. To pump the fiber, we use a modelocked laser of 4 ps, with a central wavelength of 1960 nm. With only 150 W peak power in the fiber a supercontinuum is generated from 1300 to 2600 nm taking the supercontinuum wavelength edge at -30 dB from the continuum.
Parabolic pulse generation through passive reshaping of gaussian pulses in a normally dispersive fiber
2007
We numerically and experimentally demonstrate that a Gaussian pulse can be reshaped into a pulse with a stable parabolic intensity profile during propagation in normally dispersive nonlinear fibers.
Surface plasmon polaritons on metal cylinders with dielectric core
2001
International audience; Metal-cladded dielectric cylinders with submicron diameters may serve to model coated tips used in nearfield scanning optical microscopy. The signal measured may be greatly influenced by resonance effects due to eigenmodes of the probe. Especially, using a photon scanning tunneling microscope setup, gold-coated tips have been found to detect a signal proportional to the magnetic field distributions [E. Devaux et al.. Phys. Rev. B 62, 10 504 (2000)]. This effect is attributed to cylindrical surface plasmons. We present here fully retarded calculations of the dispersion and field patterns of the nonradiative plasmon modes in cylindrical geometry. We study the effect of…
Titanium Dioxide Waveguides for Data Transmissions at 1.55 µm and 1.98 µm
2017
International audience; We demonstrate error free transmissions of 10 Gbps signals in titanium dioxide waveguides at wavelengths of 1.55 or 2 µm. An efficient coupling of light is achieved thanks to metal grating couplers and we have checked that the component could be used with standard CWDM SFP+ devices.
Near-field observation of subwavelength confinement of photoluminescence by a photonic crystal microcavity
2006
We present a direct, room-temperature near-field optical study of light confinement by a subwavelength defect microcavity in a photonic crystal slab containing quantum-well sources. The observations are compared with three-dimensional finite-difference time-domain calculations, and excellent agreement is found. Moreover, we use a subwavelength cavity to study the influence of a near-field probe on the imaging of localized optical modes. © 2006 Optical Society of America.