Quantitative plasmonic measurements using embedded phase stepping confocal interferometry

Bei Zhang, Suejit Pechprasarn, Michael Geoffrey Somekh

Research output: Journal article publicationJournal articleAcademic researchpeer-review

20 Citations (Scopus)


In previous publications [Opt. Express 20, 7388 (2012), Opt. Express 20, 28039 (2012)] we showed how a confocal configuration can form an surface plasmon microscope involving interference between a path involving the generation of surface plasmons and one involving a directly reflected beam. The relative phase of these contributions changes with axial scan position allowing the phase velocity of the surface plasmon to be measured. In this paper we extend the interferometer concept to produce an 'embedded' phase shifting interferometer, where we can control the phase between the reference and surface plasmon beams with a spatial light modulator. We demonstrate that this approach facilitates extraction of the amplitude and phase of the surface plasmon to measure of the phase velocity and the attenuation of the surface plasmons with greatly improved signal to noise compared to previous measurement approaches. We also show that reliable results are obtained over smaller axial scan ranges giving potentially superior lateral resolution.
Original languageEnglish
Pages (from-to)11523-11535
Number of pages13
JournalOptics Express
Issue number9
Publication statusPublished - 6 May 2013
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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