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A: Fachverband Atomphysik
A 29: Poster: Ultra-cold atoms, ions and BEC (with Q)
A 29.11: Poster
Mittwoch, 20. März 2013, 16:00–18:30, Empore Lichthof
Laser stabilisation techniques for cooling of Barium ions — •Julian Schmidt, Thomas Huber, Alexander Lambrecht, Michael Zugenmaier, and Tobias Schaetz — Universität Freiburg
In ion trapping experiments, the frequency of the lasers required for cooling, repumping and photoionisation needs to be just as stable as for neutral atom experiments, that is on the order of a fraction of the natural linewidth. However, since the gas is composed of neutral atoms and molecules, one cannot, in general, use established locking techniques on a gas cell filled with the chemical element in question.
For Ba+, the repumping transition at 650nm is in the vicinity of an Iodine line; however, in typical gas cells, there are no established transitions to lock the Doppler cooling laser at 493nm (which is frequency-doubled from 987nm) or the two-photon photoionisation laser at 413nm. In our experiment, we therefore implement temperature stabilised optical cavities suited to fulfill our requirements at 987nm and 413nm with sub-MHz (sub-Hz stabilisation is not required) linewidth and excellent long-term stability to produce a useful error signal.
For the future, we are investigating several options, e.g. locking the 493nm laser to a transition in the H2O molecule which is, to our knowledge, not being exploited in other Ba+-trapping experiments, or to an improved version of our current optical cavity.