CALCULATION OF THE FIELD ENHANCEMENT ON LASER-ILLUMINATED SCANNING PROBE TIPS BY THE BOUNDARY-ELEMENT METHOD

In the near field of an illuminated scanning probe tip with a dimensio n much smaller than a light wavelength a tremendous field enhancement is possible. This effect is similar to field enhancement on small meta l particles first investigated in SERS (surface-enhanced Raman spectro scopy). In this article we propose to apply the boundary element metho d (BEM) to calculate the electric potential and field for an arbitrary tip-sample geometry, BEM works especially well for the Laplace proble m with piecewise constant material properties. We developed a simple a nd fast program and carried out calculations for some tip-sample confi gurations.