Autumn 2006 article selection
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