Optical waveguiding in suspensions of dielectric particles.
An optical waveguide formed by a suspension of dielectric nanoparticles in a microchannel is described. The suspensions, chosen for their guiding and scattering properties, are silica and polystyrene particles that have diameters of 30-900 nm and are dispersed in water with volume fractions up to 10%. Changing the diameter and concentration of the particles causes the suspensions to transition from Rayleigh to Mie scattering and from single to multiple scattering. The threshold for optical guiding in a waveguide core composed of these suspensions is set by the numerical aperture of the effective refractive-index difference introduced by the suspension and not by the average interparticle distance.
Conroy
Richard S
RS
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 62138, USA. rconroy@fas.harvard.edu
Mayers
Brian T
BT
Vezenov
Dmitri V
DV
Wolfe
Daniel B
DB
Prentiss
Mara G
MG
Whitesides
George M
GM