Narrow-line-mediated Sisyphus cooling in the $^{3}\mathrm{P}_{2}$ metastable state of strontium

TL;DR

This paper demonstrates a novel narrow-line-mediated Sisyphus cooling method for magnetically trapped strontium atoms in the $^{3} extrm{P}_{2}$ state, enhancing atom number and potential applications in quantum sensors.

Contribution

The authors introduce a new cooling scheme using narrow-line transitions and optical lattices to improve atom trapping efficiency in strontium.

Findings

Achieved efficient cooling of magnetically trapped strontium atoms.

Enhanced atom number through optical pumping and continuous outcoupling.

Potential for improved quantum sensors with ultracold atomic beams.

Abstract

We demonstrate narrow-line-mediated Sisyphus cooling of magnetically trapped strontium (Sr) in the $5s5p\,^{3}\textrm{P}_{2}$ state. A 641 nm standing-wave, blue-detuned from the $5s4d\,^{3}\textrm{D}_{3}$$\,\rightarrow$ $\,5p4d\,^{3}\textrm{F}_{4}$ transition, creates a dissipative optical lattice in the $^{3}\textrm{D}_{3}$ state. By combining Doppler cooling and Sisyphus cooling on the $5s5p\,^{3}\textrm{P}_{2}$$\,\rightarrow$ $5s4d\,^{3}\textrm{D}_{3}$ transition at 2.92 ${\mu}$m, we observed efficient cooling of magnetically trapped atoms. By optically pumping the atoms to the $5s5p\,^{3}\textrm{P}_{0}$ 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.