title: Quasi one-dimensional light beam generated by a graded-index microsphere.
abstract: 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 electrodynamics 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.
authors.affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA. sch@northwestern.edu
authors.forename: Soon-Cheol
authors.initials: SC
authors.lastname: Kong
authors.forename: Allen
authors.initials: A
authors.lastname: Taflove
authors.forename: Vadim
authors.initials: V
authors.lastname: Backman
mesh_terms: D055590:Electromagnetic Phenomena; D006046:Gold; D006801:Humans; D008027:Light; D053768:Metal Nanoparticles; D008863:Microspheres; D008962:Models, Theoretical; D053758:Nanoparticles; D009369:Neoplasms / Q000175:diagnosis; D055620:Optical Phenomena; D012542:Scattering, Radiation
chemical_list: D006046:Gold