Abstract
Laser cycling of resonances can remove entropy from a system via spontaneously emitted photons, with electronic resonances providing the fastest cooling timescales because of their rapid spontaneous relaxation. Although atoms are routinely laser-cooled, even simple molecules pose two interrelated challenges for cooling: every populated rotational-vibrational state requires a different laser frequency, and electronic relaxation generally excites vibrations. Here we cool trapped AlH+ molecules to their ground rotational-vibrational quantum state using an electronically exciting broadband laser to simultaneously drive cooling resonances from many different rotational levels. Undesired vibrational excitation is avoided because of vibrational-electronic decoupling in AlH+. We demonstrate rotational cooling on the 140(20) ms timescale from room temperature to 3:8 -0.3+0.9K, with the ground-state population increasing from ∼3 to 95.4-2.1+1.3%. This cooling technique could be applied to several other neutral and charged molecular species useful for quantum information processing, ultracold chemistry applications and precision tests of fundamental symmetries.
Original language | English (US) |
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Article number | 4783 |
Journal | Nature communications |
Volume | 5 |
DOIs | |
State | Published - Sep 2 2014 |
Funding
We thank Michael Schmitt for generous help with uncertainty analysis and Michael Drewsen and Stephan Schiller for useful conversations. This work was supported by AFOSR grant no. FA9550-13-1-0116, NSF grant nos. PHY-1309701 and 0801685, and the David and Lucile Packard Foundation grant no. 2009-34713.
ASJC Scopus subject areas
- General Physics and Astronomy
- General Chemistry
- General Biochemistry, Genetics and Molecular Biology