K. Sakaki

Optical potential for atom guidance in a cylindrical-core hollow fiber

Abstract We describe a practical atomic waveguide using a cylindrical-core hollow fiber. Theoretical analyses of propagating field modes are presented for a multimode fiber. An evanescent wave leaked out to the hollow region is shown to produce a deep optical potential enough to guide atoms with low coupling laser power under an optimal blue-detuning determined by fiber parameters, exciting mode and aximuthal angle. The excitation of an HE 11 mode required for stable atomic guidance in the multimode hollow fiber is experimentally realized with the power-coupling efficiency of more than 10%.

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.

Optical guidance of neutral atoms using evanescent waves in a cylindrical-core hollow fiber: theoretical approach

Abstract An atomic waveguide made by a cylindrical-core hollow fiber is described using numerical analyses in the weakly guiding approximation. We describe a potential barrier made up of the potical potential due to evanescent waves and the attractive potential due to cavity QED effects. The feasibility of atomic guidance experiments with a Rb beam is discussed in terms of an evaluation of the potential barrier including interference effects.

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.

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.

Evanescent-field Atom Guidance In The Subwavelength Region Beyond The Diffraction Limit

By using this kind of resonator, the stability of mode-locking and output energy can be improved. The threshold of pump energy for the laser system without mode-locking (freerunning) is about 40 J. When the smallsignal transmissivity of the saturable absorber was chosen at T,, = 55% and the pump energy reached 60.5 J, stable modelocking was obtained. The optical pulsewidth of mode-locked output was 78.7 ps, and the output energy reached 57.3 mJ. The factors that affect the mode-locked laser output, such as cavity configuration, saturable absorber, and active medium have been analyzed. We believe that the system has a high potential for practical applications.