Defocus leakage radiation microscopy for single shot surface plasmon measurement

Terry W.K. Chow, Daniel P.K. Lun, Suejit Pechprasarn, Michael G. Somekh

Research output: Journal article publicationJournal articleAcademic researchpeer-review

6 Citations (Scopus)


Measurement of surface plasmon and surface wave propagation is important for the operation and characterization of sensors and microscope systems. One challenge is to perform these measurements both quickly and with good spatial resolution without any modification to the sample surface. This paper addresses these issues by projecting an image of the field excited from a defocused sample to a magnified image plane. By carefully analysing the intensity distribution in this plane the properties of the surface waves generated on the sample surface can be determined. This has the advantage over previous techniques that the data can be obtained in a single shot without any changes to the focal position of the sample. Equally importantly, we show the method measures the local properties of the sample at well-defined positions, whereas other methods such as direct observation of the back focal plane average the properties over the propagation length of the surface waves.

Original languageEnglish
Article number075401
JournalMeasurement Science and Technology
Issue number7
Publication statusPublished - Jul 2020


  • image plane
  • single shot
  • surface plasmon

ASJC Scopus subject areas

  • Instrumentation
  • Engineering (miscellaneous)
  • Applied Mathematics


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