title: Observation of two-photon absorption at low power levels using tapered optical fibers in rubidium vapor.
abstract: Nonlinear optical effects can be enhanced in tapered optical fibers with diameters less than the wavelength of the propagating light. Here we report on the observation of two-photon absorption using tapered fibers in rubidium vapor at power levels of less than 150 nW. Transit-time broadening produces two-photon absorption spectra with sharp peaks that are very different from conventional line shapes.
authors.affiliation: Physics Department, University of Maryland, Baltimore County, Baltimore, 21250, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Hendrickson
authors.forename: M M
authors.initials: MM
authors.lastname: Lai
authors.forename: T B
authors.initials: TB
authors.lastname: Pittman
authors.forename: J D
authors.initials: JD
authors.lastname: Franson