CONFINEMENT AND BISTABILITY IN A TAPERED HEMISPHERICALLY LENSED OPTICAL-FIBER TRAP

We describe the operation and performance of a dual fiber optical trap created using tapered lensed optical fibers pigtailed to 1300 nm laser diodes. Single-mode fibers, having mode field diameters of ∼9.5 μm, and separated by up to 350 μm, are used to demonstrate dielectric particle confinement over two orders of magnitude in fiber trapping power ratio. Axial and transverse trap efficiencies, as well as the existence of bistable trapping positions, are predicted and experimentally confirmed. The use of fiber lenses results in the creation of an optical trap that provides strong transverse optical confinement and which is nearly insensitive to the fiber polarization state.© 1995 American Institute of Physics.