Colloquium: Luis Orozco

ABSTRACT:   Nanofibers produced by tapering an ordinary single mode optical fiber to diameters of half a micron are interesting optical objects. Evanescent fields, with large gradients, develop as the radius reaches less than the wavelength of light posing puzzles, questions, and opportunities. The geometry of the nanofiber mode allows for study of quantum optical effects in a one-dimensional configuration, with the preferential evanescent mode of fiber accessible when good adiabatic geometry allows high coupling back into the single mode fiber.

Recent experiments with cold Rb atoms around the nanofiber include the modification of the lifetime of the D2 line in the presence of the nanofiber and its relation to the single atom coupling. We find modification of the lifetime that depends on the alignment of the dipole with respect to the nanofiber: parallel or perpendicular. We also explore collective effects in the decay from the atomic excited that depend on the number of atoms interacting in the evanescent mode of the nanofiber. Polarimetry measurements with trapped atoms show dynamics of the trap atoms with distinctive frequencies in the radial and azimuthal direction.