Large dielectric non-spherical particle in an evanescent wave field near a plane surface Yuri Eremin a , Thomas Wriedt b, * a Department of Applied Mathematics and Computer Science, Moscow State University, Vorobyov Hills, Moscow 119899, Russia b Institut f€ ur Werkstofftechnik, Badgasteiner Str. 3, 28359 Bremen, Germany Received 12 April 2002; received in revised form 28 June 2002; accepted 28 October 2002 Abstract In this paper we present an extended scheme of the Discrete Sources Method applied to the analysis of scattering of evanescent waves by a large particle deposited on a prism surface. Computer simulation results relating to the influence of uncertainties in particle diameter, refractive index and particle shape are analysed. Ó 2002 Elsevier Science B.V. All rights reserved. Keywords: Evanescent wave scattering; Scattering microscopy; Discrete Sources Method 1. Introduction The wide potential of application of scattering microscopy especially in biology, materials science and information technology gives rise to renewed interest in computer simulation of scattering of evanescent waves by a particle located near a di- electric prism surface [1–3]. In the past mainly scattering by spherical particles has been analysed by approximate models not fully taking into ac- count particle–surface scattering interaction. In recent papers by Doicu et al. [4,5] a computer model for evanescent wave scattering analysis has been developed based on the Discrete Sources Method (DSM). The model takes into account complete scatterer–prism interaction and provides an opportunity to investigate evanescent wave scattering by any axial symmetric scatterer. It has been demonstrated that only exact models and not just approximate models adequately describe scattering of evanescent waves by a particle near a plane surface [4]. In the present paper we present an improved scheme of DSM enabling to analyse an even larger particle near the plane surface. The new version of DSM gives an extension of its range of validity from particle diameter 1 to 5 lm for an incident wavelength k 0 ¼ 632:8 nm. The real need to investigate scattering by larger particles consists in the necessity to calibrate modern particle scan- ner design to be able to demonstrate its ability to measure several orders of magnitude of scattered intensity [3]. Optics Communications 214 (2002) 39–45 www.elsevier.com/locate/optcom * Corresponding author. Tel.: +49-421-218-2507; fax: +49- 421-218-5378. E-mail addresses: eremin@cs.msu.su (Y. Eremin), thw@iwt.uni-bremen.de (T. Wriedt). 0030-4018/02/$ - see front matter Ó 2002 Elsevier Science B.V. All rights reserved. PII:S0030-4018(02)02174-0