Angular criterion to distinguish between Fraunhofer and Fresnel diffraction
Abstract:The distinction between Fresnel and Fraunhofer diffraction is an essential condition for the accurate analysis of diffracting structures. In this paper we propose a criterion based on the angle subtended by the first minimum of the diffraction pattern from the centre of the diffracting aperture. The determination of the minimum of the diffraction pattern is the crucial point to assure the accuracy of the criterion. Therefore, the applicability of adequate thresholds for detection is discussed. The criterion is also generalized by expressing it in terms of the number of Fresnel zones delimited by the aperture. Simulations are reported to illustrate the feasibility of the criterion.
Document Type: Research Article
Affiliations: 1: Institute of Physics, Universidad de Antioquia, A.A. 1226, Medellín, Colombia 2: AS-ICTP Regular Associate, Physics School, Universidad Nacional de Colombia Sede Medellín, A.A. 3840, Medellín, Colombia 3: Department of Physics, Università degli Studi di Bologna and Istituto Nazionale per la Fisica della Materia, INFM, Viale B. Pichat 6/2, I-40127 Bologna, Italia
Publication date: 2004-12-01