Search results for "Photonic"
showing 10 items of 1274 documents
Hf02 based RRAM: from materials engineering to integrated modules
2015
10 mars 2015; International audience; no abstract
Designed surface modes propagating along hyperbolic metamaterials
2013
We report on surface-wave propagation (SWP) that occurs in semi-infinite hyperbolic metamaterials whose optical axis is set in the interface plane. In practice it is implemented by a multi-layered metal-dielectric nanostructure that is cut normally to the layers. Our theoretical analysis shows that various conditions can be designed enabling distinct regimes of SWP. We concluded that hybridization of SWP polarization leads to tighter confinement near the interface as compared with conventional surface plasmon polaritons. By using the finite-element method (FEM), we demonstrate that the fields are enhanced on the walls of metallic films, and thus minimizing significantly its presence inside …
Tuning four-wave mixing through temperature in ethanol-filled photonic crystal fiber
2016
In this paper, continuous tuning of four-wave mixing bands in an ethanol-filled photonic crystal fiber is investigated. A wide tuning range of the parametric bands, from 745 nm to 920 nm (signal) and from 1260 nm to 1710 nm (idler), is achieved through the thermo-optic effect. This corresponds to a frequency tuning range higher than 2000 cm−1; such wide range can be particularly useful in applications that require broadband wavelength conversion, e.g., CARS microscopy. Numerical calculations are in good agreement with experimental measurements.
Lateral magnification matrix from the dioptric power matrix formalism in the paraxial case.
2012
Background Previous studies have highlighted that power matrices fully characterize the concept of dioptric power of any astigmatic surface. Thus, the basic equations in physiological optics can be generalized using the matrix formalism of the dioptric power. Among others, lateral magnification has also been interpreted as a matrix but mainly concerning magnification modification induced by spectacle correction of refractive error. Purpose To provide a fresh look into a novel paraxial formulation for the assessment of the lateral magnification using power matrices and in presence of astigmatism for thin and thick imaging systems in general. Methods Linear optics provides the frame to genera…
40-GHz photonic waveform generator by linear shaping of four spectral sidebands
2015
International audience; We show that the amplitude and phase shaping of only four sidebands of the optical spectrum is sufficient to synthesize parabolic, triangular, or flat-top pulse trains at high repetition rates. Selection of the symmetric carrier-suppressed waveform is easily achieved by changing the phase difference between the inner and outer spectral lines. Experiments carried out at a repetition rate of 40 GHz confirm the high quality of the intensity profiles that are obtained.
Accurate mode characterization of two-mode optical fibers by in-fiber acousto-optics.
2016
Acousto-optic interaction in optical fibers is exploited for the accurate and broadband characterization of two-mode optical fibers. Coupling between LP01 and LP1m modes is produced in a broadband wavelength range. Difference in effective indices, group indices, and chromatic dispersions between the guided modes, are obtained from experimental measurements. Additionally, we show that the technique is suitable to investigate the fine modes structure of LP modes, and some other intriguing features related with modes' cut-off.
Demonstration of polarization pulling in a fiber-optical parametric amplifier
2012
International audience; We report the experimental demonstration of all-optical polarization pulling of an initially polarization-scrambled signal using a fiber-optical parametric amplifier. Nonlinear polarization pulling has been achieved for both the signal and idler with 25 dB gain.
Surface-plasmon hopping along coupled coplanar cavities
2007
International audience; We report on surface-plasmon propagation along coupled coplanar cavities periodically distributed in an otherwise unperturbed plasmonic crystal. We show that the dispersion of particular Bloch modes can exhibit multiple energy gaps that can be adjusted by choosing the cavity size. For resonant sizes, the composite crystals composed of juxtaposed cavities can support plasmon modes at frequencies within the gap of the unperturbed grating. In this case, we demonstrate that the surface-plasmon propagation relies on a hopping mechanism.
Emergence of extreme events in fiber-based parametric processes driven by a partially incoherent pump wave
2009
Modulation instability (MI) generated by a picosecond coherent pulse has been recently identified as the key element of the generation of optical rogue-waves in supercontinuum-based systems [1]. Similar rare but highly energetic pulse structures can also appear in non-solitonic configurations such as Raman amplifiers driven by a partially incoherent pump wave propagating in fibres with low group velocity dispersion [2]. Therefore, one may wonder whether optical rogue-like event can also occur in MI-based amplifier because both Raman and parametric amplifiers benefit from a quasi-instantaneous gain. We provide here experimental evidence of rare optical events in a parametric amplifier in pre…
Spontaneous emission of an atom in a dynamical photonic crystal
2014
A structured environment such as a photonic crystal can strongly affect radiative properties of an atomic system, for example the spontaneous emission process. Recently there has been also an increasing interest on dynamical photonic crystal, that is photonic crystals whose dielectric properties change on time. We consider the spontaneous emission of an atom placed inside a photonic crystal with time-dependent properties (dynamical photonic crystal). We investigate the atomic spontaneous emission in two different regimes, weak and strong coupling, assuming a small, periodic and adiabatic perturbation of the crystal. In the weak coupling case, we analytically obtain the spontaneous emission …