Optical-dipole noise

L. J. Wangt, A. M. Bacon, Hongxi Zhao +1 more

Jun He, Baodong Yang, Yongjie Cheng +2 more

In our experiment, a single cesium atom prepared in a large-magnetic-gradient magneto-optical trap (MOT) can be efficiently transferred into a 1064-nm far-off-resonance microscopic optical dipole trap (FORT). The efficient transfer of the single atom between the two traps is used to determine the trapping lifetime and the effective temperature of the single atom in FORT. The typical trapping lifetime has been improved from ∼ 6.9 s to ∼ 130 s by decreasing the background pressure from ∼ 1 × 10 −10 Torr to ∼ 2 × 10 −11 Torr and applying one-shot 10-ms laser cooling phase. We also theoretically investigate the dependence of trapping lifetimes of a single atom in a FORT on trap parameters based on the FORT beam’s intensity noise induced heating. Numerical simulations show that the heating depends on the FORT beam’s waist size and the trap depth. The trapping time can be predicted based on effective temperature measurement of a single atom in the FORT and the intensity noise spectra of the FORT beam. These experimental results are found to be in agreement with the predictions of the heating model.

Galina A. Nemova

Pascal E. Blessing

Optical dipole traps are often used to provide an ultra-cold atom gas. Red detuned dipole traps are in principal rather easy to implement since they only consist of a focussed laser beam and without great complexity a potential minimum can be achieved. Bigger issues are the optimization of these traps as the intensity noise of the cw laser needs to be stabilized and thermal effects due to the high laser power traveling though the optical elements need to be minimized.

Ulrich Hohenester

John J. McFerran, Sinda Mejri, L. Yi +1 more

We describe our work to develop an optical lattice clock using neutral mercury, which has the potential to reach accuracy near 1 part in 1018owing to its low sensitivity to black body radiation. We describe developments of our experimental setup to allow dipole lattice trapping and spectroscopy in the Lamb-Dicke regime. Specifically, we report on the implementation of a low noise imaging and detection system, on the characterization of the magneto-optic trap from which the dipole trap will be loaded, on the implementation of the dipole lattice trap itself, a challenging task given the wavelength and power requirements.