Articles récents

Next meeting : BCP Marseille Dec 03rd

22 Novembre 2007 , Rédigé par JW Publié dans #Nanophotonics pick

Scientific meeting of Marseille’s community of biologists, chemists and physicists. The webpage is somehow difficult to find so here a direct link :
 

http://www.fresnel.fr/mosaic/BCP/journee.html


Training periods and PhD positions in optics & biophotonics

29 Octobre 2007 , Rédigé par JW Publié dans #Recent research work

The Mosaic group at the Institut Fresnel offers training periods for graduate students in optics and photonics. PhD positions are also available based on the different internship subjects, depending on the applicant’s profile and fundings (read more about this topic in my previous post here). More information can be found on the MOSAIC website.

I would like to give a special emphasis to the subject I propose following this link:

http://www.fresnel.fr/mosaic/jobs/pdf_files/Nanoapertures%20JW.pdf


Summer 2007 article selection

27 Octobre 2007 , Rédigé par JW Publié dans #Nanophotonics pick

As member of the OMNT “materials and components for optics” committee, I regularly give a selection and a brief description of articles, that I found particularly relevant to the field. Here is my latest selection :

 

"Generation of optical Schrödinger cats from photon number states"; Alexei Ourjoumtsev, Hyunseok Jeong, Rosa Tualle-Brouri et Philippe Grangier, Nature 448, 784-786 (2007). 

Schrodinger’s cat is a Gedankenexperiment in quantum physics, in which an atomic decay triggers the death of the cat. Because quantum physics allow atoms to remain in superpositions of states, the classical cat would then be simultaneously dead and alive. By analogy, a ‘cat’ state of freely propagating light can be defined as a quantum superposition of well separated quasiclassical states—it is a classical light wave that simultaneously possesses two opposite phases. Such states play an important role in fundamental tests of quantum theory and in many quantum information processing tasks, including quantum computation, quantum teleportation and precision measurements. Recently, optical Schrodinger ‘kittens’ were prepared; however, they are too small for most of the aforementioned applications and increasing their size is experimentally challenging. Here we demonstrate, theoretically and experimentally, a protocol that allows the generation of arbitrarily large squeezed Schrodinger cat states, using homodyne detection and photon number states as resources. We implemented this protocol with light pulses containing two photons, producing a squeezed Schro¨dinger cat state with a negative Wigner function. This state clearly exhibits several quantum phase-space interference fringes between the ‘dead’ and ‘alive’ components, and is large enough to become useful for quantum information processing and experimental tests of quantum theory.


"Label-free single molecule detection with optical microcavities"; A. A. Armani, R. P. Kulkarni, S.E. Fraser, R. C. Flagan et K. J. Vahala, Science 317, 783-787 (2007). 

Current single-molecule detection techniques require labeling the target molecule. We report a highly specific and sensitive optical sensor based on an ultrahigh quality (Q) factor (Q > 1e8) whispering-gallery microcavity. The silica surface is functionalized to bind the target molecule; binding is detected by a resonant wavelength shift. Single-molecule detection is confirmed by observation of single-molecule binding events that shift the resonant frequency, as well as by the statistics for these shifts over many binding events. These shifts result from a thermo-optic mechanism. Additionally, label-free, single-molecule detection of interleukin-2 was demonstrated in serum. These experiments demonstrate a dynamic range of 1e12 in concentration, establishing the microcavity as a sensitive and versatile detector.
 

"Electromigrated nanoscale gaps for surface enhanced Raman spectroscopy"; D.R. Ward, N.K. Grady, C.S. Levin, N.J. Halas, Y. Wu, P. Nordlander et D. Nathelson, Nano Letters 7, 1396-1400 (2007).

Single-molecule detection with chemical specificity is a powerful and much desired tool for biology, chemistry, physics, and sensing technologies. Surface-enhanced spectroscopies enable single-molecule studies, yet reliable substrates of adequate sensitivity are in short supply. We present a simple, scaleable substrate for surface-enhanced Raman spectroscopy (SERS) incorporating nanometer-scale electromigrated gaps between extended electrodes. Molecules in the nanogap active regions exhibit hallmarks of very high Raman sensitivity, including blinking and spectral diffusion. Electrodynamic simulations show plasmonic focusing, giving electromagnetic enhancements approaching those needed for singlemolecule SERS.

Workshop : Plasmonics in biology and medicine

22 Octobre 2007 , Rédigé par JW Publié dans #Nanophotonics pick

I’ll attend (and give a talk) at the next workshop on plasmonics in biology and medicine, to be held on  Friday December 14th 2007 at ESPCI, 10 rue vauquelin 75005, Paris
 

Visit the website : http://gdr2588.ibl.fr/plasmon/intro_plasmonique.php
 

Registration is free !!!

Because of their unique optical properties, the use of plasmons is getting more and more important for biological and medical research. These applications include the use of surface plasmon resonance (SPR) to measure bioaffinity reactions, tailoring fluorescence properties and the use of metal colloids as new light-scattering probes fro imaging or phototherapy. 

The goal of this workshop is to provide an interdisciplinary forum for state-of-the-art methods and instrumentation related the new research area of plasmonics and related nanosystems and their applications in biology and medicine. A poster session will complete the lectures and allows everyone to exchange their ideas on plasmonic.


Latest funded project : ANR ANTARES

17 Septembre 2007 , Rédigé par JW Publié dans #Recent research work

The 3-years ANTARES project aims at fabricating and characterizing nanostructured substrates for surface enhanced Raman scattering (SERS) and fluorescence emission. The controlled arrangement of the colloidal structure and the use of single crystal colloids will enable to adapt the optical specifications in terms of spectral response and electromagnetic enhancement.

Learn more at http://icb.u-bourgogne.fr/antares/