Group Seminar at MPQ: A laser system for gray molasses cooling of Na atoms
Xingyan Chen, MPQ
MPQ Garching, Hans-Kopfermann-Str. 1
Tuesday, November 12th, 9:15am
Ultracold polar molecules are promising candidates for simulating many-body physics with long-range interactions. However, their complexity presents a challenge for reaching degeneracy. Recently a Fermi degenerate gas of polar molecules is produced through adiabatic association in a deeply degenerate mixture of atomic gases at JILA. The key technical improvement in the experiment is the implementation of gray molasses which increases the initial phase-space density of the atoms thus the degeneracy of molecules.
In this talk I will present the preparation work for D1 line gray molasses cooling of sodium atoms, which we use to sympathetically cool potassium atoms and form molecules. First, the working principle of gray molasses is investigated through a simplified model. Second, a 589 nm laser system with 80MHz frequency tuning range is built. Third, since molasses are sensitive to magnetic field, the switching off of the MOT magnetic field is measured by the microwave spectroscopy of sodium atoms.
Moreover, motivated by the need of molecular spectroscopy, I implemented a laser locking scheme with wavemeter as a frequency reference.