Two-color two-photon excitation of intra-4ƒ blue transitions in Pr 3+ :Y 3 Al 5 O 12

Bin Qing Xie, Y. M. Cheung, Swapan Kumar Gayen

王殿元, 郭艳艳

A. M. Akulshin, Dmitry Budker, Russell McLean

We demonstrate how the orientation of the Rb cell can significantly affect the intensity and spectral characteristics of both the frequency up- and downconverted fields generated by nonlinear processes in Rb vapor. The efficiency of parametric wave mixing in Rb vapor excited to the 5D5/2 level by two-color resonant laser light can be significantly increased by seeding the excitation region with coherent and directional radiation at 5.23 μm, which is resonant with the population inverted 6P3/2–5D5/2 transition. It is shown that the process of velocity-insensitive two-photon excitation is central to understanding the observed coherent blue and mid-IR light enhancements, and that velocity-insensitive and velocity-selective two-photon excitations could produce two co-existing but spectrally and spatially distinguishable mid-IR fields at 5.23 μm.

Christopher G. Levey, William M. Yen

Baodong Yang, Qiangbing Liang, Jun He +1 more

A two-color magneto-optical trap (MOT) for trapping cesium (Cs) atoms is experimentally realized. This two-color MOT employs the radiation forces due to photon scattering from the Cs 6P(3/2) F' = 5 - 8S(1/2) F" = 4 excited-state transition, which replaced one pair of the three pairs of cooling/trapping laser beams operating on a single-photon red detuning to the Cs 6S(1/2) F = 4 - 6P(3/2) F' = 5 cycling transition in a standard six-beam Cs MOT, and can cool and trap atoms on both the red-detuning and blue-detuning sides of the two-photon resonance. Employing the two-color MOT, the background-free fluorescence detection of trapped atoms has been demonstrated. This technique will be useful for observation of weak fluorescence signal radiated from single atoms in MOT.

C. Delalande, A. Mysyrowicz