Evaluation of near-field optical potentials on a nanometric sharpened fiber probe for atom trapping

摘要

Summary form only given. Recently, atom manipulation by using optical near fields has been attracting a lot of interests. Optical near field can be localized in a nanometric region, being free from the diffraction limit in contrast to propagation light. The intensity distribution of optical near field decays rapidly as an exponential-like function. Because such a spatially inhomogeneous light field can affect the resonant force on an atom (the so called dipole force), the optical near field produces the strong dipole force. Using the dipole force of the optical near field, we can expect to manipulate an atom with high spatial accuracy. Moreover, due to the resonant character of the dipole force, we can manipulate an atom species- and state-selectively. The optical near field localized in a nanometric region can be generated on the tip of a sharpened fiber-probe. This kind of fiber probe can be used for deflection of the atomic motion, and then trapping of an atom. To this end, it is very important to fabricate the fiber probe suitable for the atoms used. In this case, we must consider several parameters: a size and a shape of the tip, light intensity, frequency detuning, etc. In order to examine the optimal conditions for the fabrication, we measured and evaluated the optical near-field intensity distribution of the fiber-probe.