I’m looking for a PhD student to start on October 2007 on the topic of nanostructures to enhance optical contrasts in biophotonics. Different fundings are available depending on the candidate’s profile and motivation.Abstract : The ability to producing nanometric structures which forms controlled with a resolution of few nanometers opens new prospects in nanophotonics. Thanks to these systems, we can confine the light field, and produce strong efficient cross-sections as well as an enhancement of the light intensity. This allows to reach effects impossible to obtain with systems of larger dimensions. The aim of this PhD is to study and work on nanostructures of controlled forms to enhance optical contrasts in biophotonics (fluorescence, spontaneous and stimulated Raman scattering). In particular, we will first focus on nanometric holes made in metallic films (gold, silver and aluminum). These structures have remarkable properties, specifically their ability of local enhancement of the electromagnetic field. Several properties are still to be discovered: from the understanding of fundamental phenomena to the development of applications in biophotonics.
Download a proposal here and look for more information on the MOSAIC website.
Young’s double slit experiment explained in a classical and in a quantum world. It's worth having a look !
Note : it's seems the link doesn't work properly on every computer, just copy and paste the address in the directory.
I would like to support here a link to Marcel Leutenegger’s webpages on facilities towards optics learning and teaching. Very nice videos introducing the principles of image formation are available (to watch the videos, you’ll need a DivX decoder, see Marcel’s help webpage).
By the way, I would also like to acknowledge Marcel’s nice work on microscopy at Theo Lasser’s group (EPFL,
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. More information can be found on the MOSAIC website.
I would like to give a special emphasis to the subject I propose (in French) :
L'interaction entre la lumière et une structure métallique de taille nanométrique donne accès à des effets impossibles à obtenir avec des systèmes de taille supérieure. Notre équipe s'intéresse à des trous nanométriques percés dans des films métalliques. Ces structures possèdent des propriétés remarquables, notamment leur capacité d'exaltation locale du champ lumineux. De nombreuses propriétés restent encore à défricher, de la compréhension des phénomènes fondamentaux au développement d'applications en nanophotonique et biophotonique.
Le sujet de stage proposé vise à s'intégrer dans le groupe de recherche pour participer aux développements et aux expériences en cours. Une orientation plutôt optique ou plutôt biologie sera possible suivant la sensibilité du candidat, avec toujours une forte composante expérimentale.
Title : Single-scattering theory of light diffraction by a circular subwavelength aperture in a finitely conducting screen
Authors : Evgeny Popov, Michel Nevière, Anne Sentenac, Nicolas Bonod, Anne-Laure Fehrembach, Jérome Wenger, Pierre-François Lenne, and Hervé Rigneault
It has been released in the February edition of the journal of the optical society of JOSA A, vol. 24, pp. 339-358 (2007). Click here to read the abstract and download the paper (subscribers only).
This theoretical paper provides analytical formulas for the electromagnetic field diffracted by a subwavelength aperture in an opaque screen (metallic or dielectric). My contribution to these findings is very small, my name was put on the paper mostly because of the ongoing collaboration between the theoretical and experimental groups at the Fresnel Institute.In my opinion, the main application concerns the far-field directivity from a nanoaperture (part 6, figures 8 to 11). The theory predicts a directivity of the radiation pattern that increases for small permittivities. Surprisingly, this holds for metals AND dielectrics, thus independently of surface plasmon excitation.