Scattering by particles on or near a plane surface

Abstract

Computation of light scattering from particles deposited upon a surface is of great interest in the simulation, development and calibration of surface scanners for wafer inspection [1]. More recent applications include laser cleaning [2], scanning near-field optical microscopy (SNOM) [3] and plasmon resonances effects in surface-enhanced Raman spectroscopy (SERS) [4]. Several studies have addressed this scattering problem using different methods. Simplified theoretical models have been developed on the basis of Lorenz-Mie theory and Fresnel surface reflection [5–8]. A coupled-dipole algorithm has been employed by Taubenblatt and Tran [9] and Nebeker et al. [10] using a three-dimensional array of dipoles to model a feature shape and the Sommerfeld integrals to describe the interaction between a dipole and a surface. The theoretical aspects of the coupled-dipole model has been fully outlined by R. Schmehl [11]. A model based on the discrete source method has been given by Eremin and Orlov [12,13], whereas the transmission conditions at the interface are satisfied analytically and the fields of discrete sources are derived by using the Green tensor for a plane surface. More details on computational methods and experimental results can be found in a book edited by Moreno and Gonzales [14].