I have guided micron and nanometer size particles (in fluid and gases background) in hollow optical fibers using laser light at a wavelength of 780nm. Optical radiation pressure (scattering & absorption forces) and gradient forces are used to funnel particles into the hollow fiber. The fiber guides the laser light in a grazing incident optical mode and, in turn, the optical forces escort the particles through the fiber. A wide range of particles can be guided including dielectrics, semiconductor, and metals. For example, 100nm diameter Au particles were guided in a 31 micron diameter hollow fiber in water background. The laser's wavelength was 780nm and the output power was 0.4 watts. The calculated force from radiation pressure was 2x10-14N and the measured force was 7.98x10-14N. The measured mean velocity of the particles near the entrance of the fiber was 84.5x10-6 m/s.
Frank Underdown Jr.
Physics Department, Michigan Tech. University
Houghton, MI 49931