jw-photonics-inside

A copy of my PhD thesis can be downloaded here (supervisor Philippe Grangier).

This work aims at exploiting the quantum properties of light in order to develop new communication devices. The study is devoted to the quadrature components (quantum continuous variables) of a single mode of the electromagnetic field in the pulsed regime. A quantum key distribution protocol using coherent states has been demonstrated, and opens the way for practical high-rate quantum cryptography devices.

In order to study the use of quantum specificities such as squeezing and entanglement, we have developed a new source of pulsed squeezed states and entangled states. This source is based on the nonlinear conversions of ultrashort pulses. We also describe the first observation of a degaussification protocol, that maps individual pulses of squeezed vacuum onto non-Gaussian states. Finally, we study some optical set-ups allowing for a loophole-free Bell test using continuous variables and efficient homodyne detections.

Keywords
Quantum information - quantum communication - quantum cryptography - continuous variables - pulsed homodyne detection - femtosecond pulses - parametric amplification - squeezed states - non-Gaussian states - entanglement - Bell's inequalities

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 :

 

"Creating hot nanoparticle pairs for surface enhanced Raman spectroscopy through optical manipulation"; Fredrik Svedberg, Zhipeng Li, Hongxing Xu, Mikael Käll, Nano Letters 6, 2639-2641 (2006).

Abstract : We use optical tweezers to move single silver nanoparticles into near-field contact with immobilized particles, forming isolated surfaceenhanced Raman spectroscopy (SERS) active Ag particle dimers. The surface-averaged SERS intensity increases by a factor 20 upon dimerization. Electrodynamics calculations indicate that the final approach between the particles is due to “optical binding”. The described methodology may facilitate controlled single molecule SERS analysis.

 

"Enhancing sensitivity of a whispering gallery mode biosensor by subwavelength confinement"; O. Gaathon, J. Cullic-Viskota, M. Mihnev, I. Terakoa, S. Arnold, Applied Physics Letters 89, 223901 (2006).

Abstract : the authors demonstrate enhanced sensitivity of a spherical whispering gallery mode biosensor WGMB by confining orbiting light near the surface using a subwavelength high refractive index layer on a fluorine doped silica microsphere. Their experiments at a free space wavelength of 1310 nm show that the frequency shift sensitivity by changing the external refractive index is increased by more than 700% by adding a 340 nm thick polystyrene layer. This advance is expected to move the WGMB well into the lead as the most sensitive method for unlabeled biosensing.

 

"Shining new light on neural circuits"; Greg Miller, Science 314, 1674-1676 (2006).

Abstract : Emerging methods that combine genetics and optics have neuroscientists glowing about the possibilities

An amazing video found on Google :

http://video.google.fr/videoplay?docid=-4237751840526284618&q=physics&pr=goog-sl

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.