Gaussian beam scattering from spheres using morphology-dependent resonances
Abstract
Electromagnetic (EM) radiation propagating inside a dielectric particle will develop standing waves if certain boundary conditions are satisfied. The boundary conditions depend on, among other things, the shape of the particle. The standing-wave solutions are widely referred to as morphology-dependent resonances (MDRs). If MDR conditions are satisfied then the intensity of the electric field can be calculated everywhere inside the particle. It has been found that for certain MDR modes in micron-sized spheres the EM field strength is localized close to the particle surface. Energy can be transferred into these MDRs through Gaussian laser beam scattering from the sphere, and the energy becomes trapped in a semi-bound state. The localization and increased lifetimes of MDRs allows them to be used in stimulated Raman scattering experiments. Calculations have shown that the maximum energy is transferred into the MDR when the laser is focused outside the sphere surface. This paper analyzes the internal and external radial wavefunctions involved in the scattering to determine the optimum position of the Gaussian beam.
- Publication:
-
Laser Techniques for Surface Science II
- Pub Date:
- September 1995
- DOI:
- 10.1117/12.221489
- Bibcode:
- 1995SPIE.2547..359M