We demonstrate narrow-line-mediated Sisyphus cooling of magnetically trapped strontium (Sr) in the 5s5p\, ^3P₂ state. A 641 nm standing-wave, blue-detuned from the 5s4d\, ^3D₃\, \, 5p4d\, ^3F₄ transition, creates a dissipative optical lattice in the ^3D₃ state. By combining Doppler cooling and Sisyphus cooling on the 5s5p\, ^3P₂\, 5s4d\, ^3D₃ transition at 2. 92 μm, we observed efficient cooling of magnetically trapped atoms. By optically pumping the atoms to the 5s5p\, ^3P₀ state, we facilitate continuous outcoupling via a moving optical lattice with two fold improvement in atom number. Our scheme applies to next-generation quantum sensors using continuous ultracold atomic beams.
Chen et al. (Tue,) studied this question.