Trapping and cooling rubidium in far-off-resonant optical dipole traps

John Douglas Miller

A. Fioretti, Jérôme Lozeille, Carlo Andrea Massa +2 more

Nuttanan Tanasanchai, Kritsana Srakeaw, Parinya Udommai +1 more

We present an asymmetric focused-beam trap (FBT) of cold Rubidium-85 atoms.Unlike the cold atom preparation using the magneto-optical trap, the FBT has its path of cooling beam occupying only one axis.Since the experiments on these cold atoms usually require additional laser beams or other atom interacting sources, the FBT allows more optical and physical accessibility for these experiments.In our experiment, the cooling beams only occupied one axis, and the crossed repumping beams were in the transverse plane to the cooling beams.By varying the intensity of the repump laser, we have shown that the atomic cloud density can be monotonically manipulated from zero to the maximum value limited by the cooling power.With this monotonic control, we then computationally introduced a scheme for the precision loading of 1-6 atoms into the far-off-resonance optical dipole trap (FORT).Using the FBT for precision FORT loading could enable extensions toward the research areas, such as Rydberg atom, quantum simulation, and quantum computing.

T. Ido, Yoshitomo Isoya, Hidetoshi Katori

Employing a far-off resonance optical-dipole trap (FORT), we attained a phase-space density exceeding 0.1, or an order to quantum degeneracy. Strontium atoms were magneto-optically cooled and trapped using the spin-forbidden ${}^{1}{S}_{0}{\ensuremath{-}}^{3}{P}_{1}$ transition and then compressed into a FORT that was designed to allow simultaneous Doppler cooling. We discussed that the phase-space density was finally limited by the light-assisted collisions occurring in the optical cooling.

Junmin Wang, Yongjie Cheng, Shanlong Guo +2 more

Optical dipole traps (ODT) with far-off-resonance laser are important tools in more and more present cold-atom experiments, which allow confinement of laser-cooled atoms with a long storage time. Particularly, the magic wavelength ODT can cancel the position-dependent spatially inhomogeneous light shift of desired atomic transition, which is introduced by the ODT laser beam. Now it plays an important role in the state-insensitive quantum engineering and the atomic optical clock. To verify the magic wavelength or the magic wavelength combination for D2 line transition of cesium (Cs) and rubidium (Rb) atoms, we calculated and analyzed the light shift of the 133Cs 6S1/2 - 6P3/2 transition for a monochromatic ODT, and also the 87Rb 5S1/2 - 5P3/2 transition for a dichromatic ODT with a laser frequency ratio of 2:1. Also a dichromatic magic-wavelength ODT laser system for 87Rb atoms is proposed and experimentally realized by employing the quasi-phase-matched frequency doubling technique with telecom laser and fiber amplifier.

Sebastiaan L. Meyer Viol