State-insensitive dichromatic optical-dipole trap for rubidium atoms: calculation and the dicromatic laser's realization

摘要

Magic wavelength optical-dipole trap (ODT) allows confinement of neutral atoms and cancellation of the position-dependent spatially inhomogeneous differential light shift for a desired atomic transition. The light shift of the ~(87)Rb 5P_(3/2) state can be expediently tailored to be equal to that of the ~(87)Rb 5S_(1/2) state by employing dicromatic (λ_1 + λ_2 (here λ_2 = 2λ_1 ～ 1.5 μm)) linearly polarized ODT lasers. In our calculation, two sets of state-insensitive dichromatic (784.3 + 1568.6 nm and 806.4 + 1612.8 nm) are obtained for the ~(87)Rb 5S_(1/2) (F = 2) - 5P_(3/2) (F' = 3) transition. Further, 784.3 + 1568.6 nm dicromatic laser system with a moderate output power has been realized experimentally by marrying efficient second-harmonic generation using a PPMgO:LN bulk crystal with a fibre-amplified 1.5 μm telecom laser.