Visualization of the birth of an optical vortex using diffraction from a triangular aperture

A. Mourka, J. Baumgartl, C. Shanor, K. Dholakia, E. M. Wright

Research output: Contribution to journalArticlepeer-review

107 Scopus citations


The study and application of optical vortices have gained significant prominence over the last two decades. An interesting challenge remains the determination of the azimuthal index (topological charge) l of an optical vortex beam for a range of applications. We explore the diffraction of such beams from a triangular aperture and observe that the form of the resultant diffraction pattern is dependent upon both the magnitude and sign of the azimuthal index and this is valid for both monochromatic and broadband light fields. For the first time we demonstrate that this behavior is related not only to the azimuthal index but crucially the Gouy phase component of the incident beam. In particular, we explore the far field diffraction pattern for incident fields incident upon a triangular aperture possessing non-integer values of the azimuthal index l. Such fields have a complex vortex structure. We are able to infer the birth of a vortex which occurs at half-integer values of l and explore its evolution by observations of the diffraction pattern. These results demonstrate the extended versatility of a triangular aperture for the study of optical vortices.

Original languageEnglish (US)
Pages (from-to)5760-5771
Number of pages12
JournalOptics Express
Issue number7
StatePublished - Mar 28 2011

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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