Computation of tightly-focused laser beams in the FDTD method

Ilker R. Çapoǧlu*, Allen Taflove, Vadim Backman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


We demonstrate how a tightly-focused coherent TEMmn laser beam can be computed in the finite-difference time-domain (FDTD) method. The electromagnetic field around the focus is decomposed into a plane-wave spectrum, and approximated by a finite number of plane waves injected into the FDTD grid using the total-field/scattered-field (TF/SF) method. We provide an error analysis, and guidelines for the discrete approximation. We analyze the scattering of the beam from layered spaces and individual scatterers. The described method should be useful for the simulation of confocal microscopy and optical data storage. An implementation of the method can be found in our free and open source FDTD software ("Angora").

Original languageEnglish (US)
Pages (from-to)87-101
Number of pages15
JournalOptics Express
Issue number1
StatePublished - Jan 14 2013

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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