Mon Aug 7 08:46:30 BST 2006
- Title: Efficient Photoionization-Loading of Trapped Cadmium Ions with Ultrafast Pulses
- Authors: L. Deslauriers, M. Acton, B. B. Blinov, K.-A. Brickman, P. C. Haljan, W. K. Hensinger, D. Hucul, S. Katnik, R. N. Kohn, Jr., P. J. Lee, M. J. Madsen, P. Maunz, S. Olmschenk, D. L. Moehring, D. Stick, J. Sterk, M. Yeo, K. C. Younge, C. Monroe
- Abstract: Atomic cadmium ions are loaded into radiofrequency ion traps by photoionization of atoms in a cadmium vapor with ultrafast laser pulses. The photoionization is driven through an intermediate atomic resonance with a frequency-quadrupled mode-locked Ti:Sapphire laser that produces pulses of either 100 fsec or 1 psec duration at a central wavelength of 229 nm. (...)
Multiple optical traps using a mesh diffraction element
Tue Jul 18 08:51:15 BST 2006
- Title: Multiple optical traps from a single laser beam using a mechanical element
- Authors: J.A. Dharmadhikari, A.K. Dharmadhikari, D. Mathur
- Abstract: The use of a wire mesh facilitates creation of multiple optical traps for manipulation of small micron or sub-micron particles. Such an array of optical traps can be easily controlled. The trap that is formed in this manner is a continuous trap; it obviates the need to time share a laser beam among a set of positions, as is presently done in conventional multiple traps.
- Comments: The aim of the paper is to construct an optical tweezer arrangement having multiple trapping regions. The standard optical tweezer setup produces a single trapping region by focussing a laser through a microscope objective. (...)
Decoherence of motional states
Mon Jul 17 14:06:11 BST 2006
I am working on a paper at the moment describing the Schroedinger cat experiments that we performed with a single ion coupled to its motional state. In the referee comments there were a number of questions about the theoretical derivations. The majority I could answer as they related to the details of our particular experiment and analysis, however for the more fundamental ones I needed to ask one of my coauthors and he referred to the paper [Phys. Rev. A. 62 053807] by Turchette et al. This seems to be a useful for a lot of the theoretical results in the area of coupling between an ion and a bath of harmonic oscillators, as well as describing some very nice experiments.
Coupling of a charged harmonic oscillator with the surrounding electric field, E from the environment is of the form
V = -q x.E
where q is the charge on the particle and x is the position. (...)
Cooling with ultrafast lasers
Tue May 30 10:32:46 BST 2006
- Title: Broadband laser cooling of trapped atoms with ultrafast pulses
- Authors: B.B. Blinov, R.N. Kohn Jr., M.J. Madsen, P. Maunz, D.L. Moehring, C. Monroe
- Abstract: We demonstrate broadband laser cooling of atomic ions in an rf trap using ultrafast pulses from a modelocked laser. The temperature of a single ion is measured by observing the size of a time-averaged image of the ion in the known harmonic trap potential. While the lowest observed temperature was only about 1 K, this method efficiently cools very hot atoms and can sufficiently localize trapped atoms to produce near diffraction-limited atomic images.