Quasi one-dimensional light beam generated by a graded-index microsphere.
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.
Kong
Soon-Cheol
SC
Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA. sch@northwestern.edu
Taflove
Allen
A
Backman
Vadim
V
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
D006046:Gold