Search results for "Physics::Optics"
showing 10 items of 1958 documents
Analysis of the Bloch mode spectra of surface polaritonic crystals in the weak and strong coupling regimes: grating-enhanced transmission at oblique …
2004
The Bloch mode spectrum of surface plasmon polaritons (SPPs) on a finite thickness metal film has been analyzed in the regimes of weak and strong coupling between SPP modes on the opposite film interfaces. The SPP mode dispersion and associated field distributions have been studied. The results have been applied to the description of the light transmission through thick and thin periodically structured metal films at oblique incidence. In contrast to normal incidence, all SPP Bloch modes on a grating structure participate in the resonant photon tunnelling leading to the transmission enhancement. However, at the angle of incidence corresponding to the crossing of different symmetry film SPP …
Wavelength dependence of multiphoton ionization of xenon
2004
International audience; We have studied the multiphoton ionization of xenon atoms by 160 fs pulses at intensities of 531012 and 1.331013 W/cm2 and present photoelectron kinetic energy and angular distribution spectra measured with a photoelectron imaging spectrometer. A noncollinear optical parametric amplifier allows us to tune the wavelength of the laser pulse over a range between 500 and 700 nm. Resonant and nonresonant processes as well as channel switching effects have been observed in this intensity and wavelength regime. Mainly resonant s5+1d-photon ionization via ns, nd, and nd8 Rydberg states was studied in the region of 505–602 nm. Resonance structures were found related to the tw…
Turbulent Dynamics of an Incoherently Pumped Passive Optical Fibre Cavity: quasi-solitons and dispersive waves
2014
International audience; We study numerically and experimentally the dynamics of an incoherently pumped passive optical fibre ring cavity. We show that the cavity exhibits a quasi-soliton turbulence dynamics, whose properties are controlled by the degree of coherence of the injected pump wave: as the coherence of the pump is degraded, the cavity exhibits a transition from the quasi-soliton turbulent regime toward the weakly nonlinear turbulent regime characterized by short-lived rogue wave events. This behavior is reminiscent of the corresponding dynamics obtained in the purely conservative (Hamiltonian) problem. Experimental results are reported by using a standard telecommunication optical…
Generation and detection of optical rogue-wave like fluctuations in fiber Raman amplifiers
2009
International audience; Rogue wave-like statistics is reported in a fiber Raman amplifier. The pump-signal noise transfer leads to the development of large peak-power fluctuations following a power-law probability distribution. Discrimination of the rarest events is demonstrated.
Gold nanowire plasmonic mode photo-thermal modulation at telecom wavelengths
2014
International audience; Thermo-optical switches relying on polymer based plasmonic waveguides have been recently demonstrated for high-bit rate routing. In these devices, the active thermo-optical medium is polymer with a large thermo-optical coefficient. However, so far the role of the thermo-optical properties of the metal sustaining the plasmon mode has not been considered in details. In this study, we investigate the thermo-optical properties of plasmonic modes sustained by different purely metallic structures at telecom wavelengths. We first consider the basic situation of a SPPs mode traveling along a simple gold/air interface. By measuring the modulation depth of the SPPs signal when…
Nonlinear pulse shaping in normally dispersive fibers : experimental examples
2014
International audience; While the combination of Kerr nonlinearity with dispersion in optical fibers can seriously impair high speed optical transmissions, it also provides an attractive solution to generate new temporal and spectral waveforms. We explain in this talk how to take advantage of the progressive temporal and spectral reshapings that occur upon propagation in a normally dispersive fiber. We base our discussion on several experimental results obtained at telecommunication wavelengths.
All-fiber transform-limited spectral compression by self-phase modulation of amplitude shaped pulses
2012
International audience; We demonstrate efficient spectral compression of picosecond pulses in an all-fiber configuration at telecommunication wavelengths. Thanks to parabolic pulse shaping, a spectral compression by a factor 12 is achieved with an enhanced Strehl ratio.
Ligth by light polarization control for telecommunication applications
2010
International audience; In this work, we report for the first time the experimental achievement of an all-fibered polarization attraction, which can occur in optical fibers at telecommunication wavelengths. More precisely, we have experimentally shown that is possible to all-optically control and stabilize the state of polarization of a 10 Gbit/s telecommunication signal through the injection of a counter-propagating control pump wave. Eye diagrams recordings and bit error rate measurements have shown that this new type of all-optical function, almost lossless and instantaneous has a promising potential for telecommunication applications.
Extreme events in nature, randomness and rogue wave in optics
2012
International audience; Recent work in nonlinear fiber optics has demonstrated qualitative and quantitative links between instabilities in optical propagation and the giant destructive rogue or freak waves on the surface of the ocean. The analogy between the appearance of instabilities in optics and the rogue waves on the oceanic surface is both intriguing and attractive, as it opens up possibilities to explore the extreme value dynamics in a convenient benchtop optical environment. The purpose of this talk will be to discuss the results that have been obtained in optics, and to consider both the similarities and the differences with oceanic rogue wave counterparts. The talk will review exp…
Laser-induced field-free alignment of OCS molecule
2007
International audience; We investigate the dynamical alignment of jet-cooled OCS molecules induced by a short laser pulse. The alignment is measured through the orientational contribution of the optical Kerr effect using a second weak laser pulse as a probe. Maximum alignment is observed at conditions close to saturation of ionization. The results are analysed with a quantum mechanical model solving for the rotational dynamics.