Quasi one-dimensional light beam generated by a graded-index microsphere

Soon Cheol Kong*, Allen Taflove, Vadim Backman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

105 Scopus citations


An optically illuminated micron-scale dielectric sphere can generate a photonic nanojet - a nonresonant propagating beam phenomenon of high amplitude, narrow waist, and substantial sensitivity to the presence of nanometer-scale particles and geometric features located within the beam. Via three-dimensional finite-difference time-domain computational electro-dynamics modeling of illuminated graded-index microspheres, we have found that the useful length of a photonic nanojet can be increased by an order-of-magnitude to approximately 20 wavelengths. This is effectively a quasi one-dimensional light beam which may be useful for optical detection of natural or artificially introduced nanostructures deeply embedded within biological cells. Of particular interest in this regard is a potential application to visible-light detection of nanometer-scale anomalies within biological cells indicative of early-stage cancer.

Original languageEnglish (US)
Pages (from-to)3722-3731
Number of pages10
JournalOptics Express
Issue number5
StatePublished - Mar 2 2009

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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