Time filter

Source Type

Refregier Ph.,Ecole Centrale Marseille | Wasik V.,Ecole Centrale Marseille | Vynck K.,ESPCI ParisTech | Vynck K.,Institute doptique dAquitaine | Carminati R.,ESPCI ParisTech
Optics Letters

The theory of the intrinsic coherence, originally developed for 2D fields, is generalized in order to analyze coherence properties of light with a polarization that can fluctuate in three dimensions. Several notions, such as the concept of mean-square coherence and the capacity to describe irreversible behaviors, are demonstrated and illustrated with the example of light in 3D disordered media with frozen and nonfrozen disorders. © 2014 Optical Society of America. Source

Lozan O.,French National Center for Scientific Research | Perrin M.,French National Center for Scientific Research | Ea-Kim B.,CNRS Charles Fabry Laboratory | Rampnoux J.M.,French National Center for Scientific Research | And 2 more authors.
Physical Review Letters

In this Letter, we study the heat dissipated at metal surfaces by the electromagnetic field scattered by isolated subwavelength apertures in metal screens. In contrast to the common belief that the intensity of waves created by local sources should decrease with the distance from the sources, we reveal that the dissipated heat at the surface remains constant over a broad spatial interval. This behavior that occurs for noble metals at near infrared wavelengths is observed with nonintrusive thermoreflectance measurements and is explained with an analytical model, which underlines the intricate role played by quasicylindrical waves in the phenomenon. Additionally, we show that, by monitoring the phase of the quasicylindrical waves, the total heat dissipated at the metal surface can be rendered substantially smaller than the heat dissipated by the launched plasmon. This interesting property offers an alternative to amplification for overcoming the loss issue in miniaturized plasmonic devices. © 2014 American Physical Society. Source

Schembri F.,CNRS Laboratory of Future | Schembri F.,Institute doptique dAquitaine | Bodiguel H.,CNRS Laboratory of Future | Colin A.,CNRS Laboratory of Future
Soft Matter

We report the development and analysis of a velocimetry technique based on the short time displacement of molecular tracers, tagged thanks to photobleaching. We use confocal microscopy to achieve a good resolution transverse to the observation field in the direction of the velocity gradient. The intensity profiles are fitted by an approximate analytical model which accounts for hydrodynamic dispersion, and allow access to the local velocity. The method is validated using pressure driven flow in microfluidic slits having a thickness of a few tens of micrometers. We discuss the main drawbacks of this technique which is an overestimation of the velocity close to the walls due to the combination of molecular diffusion and shear. We demonstrate that this error, limited to a near wall region of a few micrometers thick, could be controlled by limiting the diffusion of fluorophore molecules or minimizing the bleaching time. The presented technique could be combined with standard particle imaging velocimetry to access velocity differences and allow particle trajectory analysis in microflows of suspensions. This journal is © The Royal Society of Chemistry. Source

Runge A.F.J.,University of Auckland | Aguergaray C.,Institute doptique dAquitaine | Provo R.,Southern Photonics | Erkintalo M.,University of Auckland | Broderick N.G.R.,University of Auckland
Optical Fiber Technology

We review our recent progress on the design, modeling and construction of all-normal dispersion Yb-doped fiber lasers mode-locked using a nonlinear amplifying loop mirror. The all-fiber nature of the devices we consider permits accurate numerical simulations with minimal approximations or free-running parameters, and we describe in detail a refined numerical modeling scheme that combines generalized nonlinear envelope equations with analytically simulated gain dynamics. Guided by insights obtained from numerical modeling, we have experimentally realized robust, environmentally stable laser designs that offer flexible operation performance for a wide variety of applications. In particular, the unique all-PM-fiber design makes our devices ideally suitable for industrial laser micromachining applications. © 2014 Elsevier Inc. All rights reserved. Source

Aguergaray C.,Institute doptique dAquitaine
Proceedings of SPIE - The International Society for Optical Engineering

We demonstrate herein a PM-fiber based cavity design capable of supporting many different pulse dynamics, such as soliton propagation or dissipative solitons in a dispersion managed cavity. By changing the dispersion of the fiber Bragg grating of the cavity we modify the net cavity dispersion, and thus stimulate various pulse dynamics. In particular we demonstrate the first net normal cavity, all-PM, all-fiber, dipersion managed cavity operating the in the 2μm range. Furthermore, we also demonstrate an all-fiber all-PM MOPA system capable of delivering up to 6 W of average power at 16 MHz by direct amplification of 70 ps long narrowband pulses. The amplifier stages are not fully saturated and are currently limited by the pump power available. © 2016 SPIE. Source

Discover hidden collaborations