Spatial Distribution Of Local Field Research Articles

Control of Surface Shape in Nanostructure Formed with Femtosecond Laser Pulses

This paper reports the experimental results demonstrating that the nanostructured surface of diamondlike carbon film can be shaped so as to have a sawlike pattern with obliquely incident ppolarized femtosecond laser pulses. The nanoscale surface shape was observed as functions of incident angle, superimposed number and fluence of laser pulses and characterized with height and slope angle of the inclined surface. This results show that the inclined shape is formed with the non-uniform spatial distribution of local field enhanced on the nanostructured surface.

Microscopic theory of surface-enhanced Raman scattering in noble-metal nanoparticles

We present a microscopic model for surface-enhanced Raman scattering (SERS) from molecules adsorbed on small noble-metal nanoparticles. In the absence of direct overlap of molecular orbitals and electronic states in the metal, the main enhancement source is the strong electric field of the surface plasmon resonance in a nanoparticle acting on a molecule near the surface. In small particles, the electromagnetic enhancement is strongly modified by quantum-size effects. We show that, in nanometer-sized particles, SERS magnitude is determined by a competition between several quantum-size effects such as the Landau damping of surface plasmon resonance and reduced screening near the nanoparticle surface. Using time-dependent local density approximation, we calculate spatial distribution of local fields near the surface and enhancement factor for different nanoparticles sizes.