title: Improved near-field calculations using vectorial diffraction integrals in the finite-difference time-domain method.
abstract: We present an alternative mixed-surface implementation of the Stratton-Chu vectorial diffraction integrals as a means to improve near-field calculations outside the computational domain of the finite-difference time-domain method. This approach, originally derived for far-field calculations, reduces the effect of phase errors and reduces storage costs compared to standard single-surface implementations performed using arithmetic and geometric means. All three methods are applied to a strongly forward-scattering sphere, which is the gold standard for similar simulations with a corresponding analytical Mie series solution. Additionally, the mixed surface is applied to an ensemble of theoretical flow cytometry calibration standards in optical gel. The near-field electromagnetic scattering produced by these or any arbitrary object, such as a cell, could be used to simulate images in a high-numerical-aperture microscope. The results show the mixed-surface implementation outperforms the standard techniques for calculating the near-field electromagnetic fields.
authors.affiliation: Department of Bioengineering, University of Washington, Human Photonics Laboratory, Fluke Hall, Seattle, Washington 98195, USA. ryancoe@uw.edu
authors.forename: Ryan L
authors.initials: RL
authors.lastname: Coe
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Sebiel
mesh_terms: D000818:Animals; D002138:Calibration; D060733:Electromagnetic Radiation; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D008853:Microscopy / Q000379:methods; D015233:Models, Statistical; D008962:Models, Theoretical; D016011:Normal Distribution; D055095:Optics and Photonics; D012542:Scattering, Radiation; D013997:Time Factors