Haruhiko Ito

Evanescent-light guiding of atoms through hollow optical fiber for optically controlled atomic deposition

This work demonstrates that the technique of guiding atoms through hollow optical fiber escorted by evanescent light is useful as a novel scheme of optical atom deposition. To show the feasibility of fabricating micron-sized structures with nanometric depth on a substrate, we measure the spatial distribution of the guided atom flux with a hot-wire detector. Moreover, precise control of the deposition rate is illustrated with a 1.4-μm-hollow fiber via photoionization spectroscopy. The ratio of the guided atom flux relative to the background transmission is enhanced up to 80-fold with a slightly tilted hollow fiber.

Evanescent-light induced atom-guidance using a hollow optical fiber with light coupled sideways

Abstract This work presents a new way useful for guiding of cold atoms with a hollow optical fiber escorted by blue-detuned evanescent light. To induce an atomic mirror-tunnel, we couple a guide-laser beam via total internal reflection from the side to the core of a hollow fiber with a facet ground at an angle of 45°. The guiding of Rb atoms is demonstrated with complementary detection by means of surface-ionization and two-step photoionization. The efficiency of the lateral light-coupling is also estimated from both experiment and numerical analysis.

Near-field optical guidance and manipulation of atoms

We describe guiding of neutral atoms through a hollow optical fiber with a micron-sized hollow core. Two-step photoionization experiment shows the frequency dispersion properties of the dipole interaction between an atom and an optical near field. These characteristics are advantageous to species- and state-selective manipulation of atoms. Then we discus a new scheme of atom deposition by means of the guiding technique, including a numerical simulation. We also present two methods for controlling atomic motion using a sharped optical fiber with a nanometric optical n ear field, i.e., atom deflection and atom trap. Deflection angle and trap potential are estimated based on a near-field intensity distribution derived from a Yukawa-type screened potential. The manipulation techniques are useful for precise control of atoms with a spatial accuracy beyond diffraction limit, which will lead to atomic-scale crystal growth.

Atom guidance using evanescent waves in small hollow optical fibers and its applications

We report the recent progress of the experiments on guiding atoms by evanescent waves in micron-sized hollow optical fibers. The lateral manipulation accuracy is enhanced up to 1 micron with a large increase of more than 50 times on the guided atom flux. Moreover, the frequency tuning enables the fine control of the guided flux with a numerical accuracy of 10 atom/s. The atom-guidance scheme is applied to in-line isotope separation on rubidium atoms and measurement of the cavity quantum electrodynamic effect in a cylindrical dielectric. In addition, the feasibility of fabricating micron-sized structures with nanometric depth is discussed including the manipulation of a small number of laser-cooled atoms.