Prospects for a narrow line MOT in YO

Abstract

In addition to being suitable for laser cooling and trapping in a magneto-optical trap (MOT) using a relatively broad ∼ ( 5 MHz) transition, the molecule YO possesses a narrow-line transition. This forbidden transition between the Σ X 2 and Δ ′ A 2 3 2 states has linewidth π ∼ × 2 160 kHz. After cooling in a MOT on the 614 nm Σ X 2 to Π A 2 1 2 (orange) transition, the narrow 690 nm (red) transition can be used to further cool the sample, requiring only minimal additions to the first stage system. We estimate that the narrow line cooling stage will bring the temperature from ∼1 mK to ∼10 μK, significantly advancing the frontier on direct cooling achievable for molecules.

High accuracy theoretical investigations of CaF, SrF, and BaF and implications for laser-cooling

“…We note that due to its long lifetime, the A 2 ∆ state has a narrow linewidth. As a consequence, laser-cooling on the X − ∆ transition may be used to reach a very low Doppler limit temperature [113].…”

Spectroscopy of YO from first principles

“…The A 2 Π 1/2 electronic state YO has a relatively short life time of 33 ns 12 with large diagonal Franck-Condon factors, 13 which makes this molecule well suited for cooling experiments with the potential in quantum information applications. 14 [15][16][17][18] .…”

Cold collisions of heavy Σ2 molecules with alkali-metal atoms in a magnetic field: Ab initio analysis and prospects for sympathetic cooling of SrOH(Morita1, Kłos2, Buchachenko3 et al. 2017Phys. Rev. A252441View full textAdd to dashboardCite

“…At present, coherent association of ultracold alkali-metal atoms remains the only experimental technique to produce ultracold gases of polar molecules KRb and NaK [11][12][13]. Recent advances in laser cooling and magneto-optical trapping [14][15][16][17][18], single-photon cooling [19], Sisyphus laser cooling [20,21], and optoelectrical cooling [21,22] made it possible to control and confine molecular species such as SrF, CaF, SrOH, YO, CH 3 F, and H 2 CO in electrostatic and magnetic traps at temperatures as low as a fraction of a milliKelvin [14-19, 21, 22]. Due to the intrinsic limitations of optical cooling, it is necessary to employ second-stage cooling techniques to further reduce the temperature of a trapped molecular gas to <0.1 mK [1,19].…”

“…[34] for a detailed discussion). As a result, it remains unclear whether heavy molecular radicals trapped in recent experiments [14][15][16][17][18][19] have small enough inelastic collision rates with ultracold alkali-metal atoms to allow for efficient sympathetic cooling in a magnetic trap.…”