2009 JAN 5 - (VerticalNews.com) -- According to recent research from Guanajuato, Mexico, "The self-rotation on the polarization azimuth and the formation of a supramolecular chiral structure when an elliptically polarized light beam propagates through an amorphous azopolymer film are used to implement a two-wavelength chiroptical switch."

  "The macrostructures generated by each excitation beam have different pitches, which produce different rotation angles of the polarization ellipse when an arbitrary probe beam is used. In the proposed device, one of the excitation beams is taken as a probe," wrote G. Martinezponce and colleagues ...read more

  2009 JAN 5 - (VerticalNews.com) -- According to a study from Taiwan, "Near-field optical properties and surface plasmon effects in a silver-shell nanocylinder pair with five different dielectric holes (DHs) that interact with a transverse magnetic mode incident plane wave are simulated by use of the finite-element method, which includes the investigation of particle-particle interaction."

  "The proposed structure exhibits a redshifted localized surface plasmon that can be tuned over an extended wavelength range by varying the dielectric constant in DHs and the thickness of the nanocylinder silver shell," wrote Y.F. Chau and colleagues, Ching-Yun University ...read more

  2008 NOV 24 - (VerticalNews.com) -- According to recent research from Caracas, Venezuela, "In this work, we report the thermo-optical properties of nanoparticles in colloidal suspensions. Spherical gold nanoparticles obtained by laser ablation in condensed media were characterized using thermal lens spectroscopy pumping at 532 nm with a 10 ns pulse laser-Nd-YAG system."

  "The obtained nanoparticles were stabilized in the time by surfactants (sodium dodecyl sulfate or SDS) in water with different molar concentrations. The morphology and size of the gold nanoparticles were determined by transmission electron microscopy (TEM) and UV-visible techniques. The plasmonic resonance bands in gold nanoparticles are responsible for the light optical absorption, and the positions of the absorption maximum and bandwidth in the UV-visible spectra are given by the morphological characteristics of these systems. The thermo-optical constants such as thermal diffusion, thermal diffusivity, and (dn/dT) are functions of the nanoparticle sizes and the dielectric function of the media. For these reasons, the thermal lens (TL) signal is also dependent on nanoparticle sizes. An analysis of the TL signal of the nanoparticles reveals the existence of an inverse dependence between the thermo-optical functions and the size. This methodology can be used in order to evaluate these systems and characterize nanoparticles in different media," wrote M.A. Ortega and colleagues ...read more