Difference between revisions of "Optical Loading of Magnetic Traps"
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*Hsin-I Lu | *Hsin-I Lu | ||
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*Ivan Kozyryev | *Ivan Kozyryev | ||
Revision as of 06:12, 22 September 2011
Contents
People
Post Docs
- Boerge Hemmerling
Grad Students
- Hsin-I Lu
- Julia Rasmussen
Post-Bachelor
- Ivan Kozyryev
Overview
Buffer gas loading of polar molecules into magnetic traps has been demonstrated with many molecules including CaH and NH. However, increasing phase space density via evaporative cooling or sympathetic cooling is inhibited by collisions with residual buffer gas. In the current experiment, we plan to produce a cold and clean CaH molecular beam and load CaH into a deep magnetic trap combining magnetic deceleration and optical pumping. A magnetic guide separates CaH molecules from a buffer gas beam source to produce a cold, clean molecular beam. Molecules are optical pumped between low and high field seeking states to slow and load them into a 4 Tesla deep magnetic trap. Since the trap loading scheme requires scattering of only a few photons, the method is applicable for many molecules.
We choose to study CaH molecules because of its good collisional properties. The elastic to spin-depolarization collision ratio between CaH and He is measured to be larger than 10^5. Theoretical study shows the main spin-depolarization mechanism of doublet Sigma molecules during collisions with Helium is due to mixing of the molecular wavefunction between rotational ground and excited states. The spin-rotational coupling in the rotational excited state can cause spin-depolarization. Since CaH has large rotational splitting (12K between N=0 and N=1 states), we expect it to maintain its spin orientation during collisions with other S state atoms. In addition, magnetic dipolar relaxation should be comparable to collisions between alkali atoms due to its moderate magnetic dipole moment. These properties make it a good candidate for sympathetic cooling of molecules.
Recent Publications
- Cold and Slow Molecular Beam. Hsin-I Lu, Julia Rasmussen, Matthew J. Wright, Dave Patterson, and John M. Doyle. Phys. Chem. Chem. Phys., 2011, DOI: 10.1039/c1cp21206k.
- Intense atomic and molecular beams via neon buffer-gas cooling, D. Patterson, J. Rasmussen, and J.M. Doyle. New Journal of Physics 11, 055018 (2009).
- Bright, Guided Molecular Beam with Hydrodynamic Enhancement, D. Patterson and J.M. Doyle. J of Chem Phys 126, 154307 (2007).
