Direct frequency comb two-photon laser cooling and trapping

Andrew Jayich, Xueping Long, Anthony Ransford +2 more

Ticijana Ban, Damir Aumiler, Gordana Kregar +5 more

Michael Ip, Anthony Ransford, Andrew M. Jayich +3 more

We demonstrate the use of a frequency-doubled optical frequency comb to load, cool, and crystallize trapped atomic ions as an alternative to ultraviolet (UV) or even deep UV continuous-wave lasers. We find that the Doppler shift from the atom's oscillation in the trap, driven by the blue-detuned comb teeth, introduces additional cooling and amplification which gives rise to steady-state phonon lasing of the ion's harmonic motion in the trap. The phonon laser's gain saturation keeps the optical frequency comb from continually adding energy without bound. This protection allows us to demonstrate loading and crystallization of hot ions directly with the comb, eliminating the need for a continuous-wave cooling laser, a technique that is extendable to the deep UV.

Andrew M. Jayich, Xueping Long, Wesley C. Campbell

Ensembles of ultracold atoms suffer only minimally from thermal fluctuations and, accordingly, are useful in a variety of fields. A new laser-cooling technique is demonstrated that can be applied to simple, abundant atoms such as hydrogen and carbon.

Jean-Louis Basdevant, Jean Dalibard