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The light for our six beam Magneto-Optical-Trap (MOT) is generated by two master diode lasers (Rb87 , 780nm) and a Titanium-Sapphire laser (K40, 767nm). The following image shows schematically our optical setup.
All light is amplified by two Tapered-Amplifiers and injected into one single fiber. This way, we operate the two-colour MOT with a single mirror-set. You can find more detailed informations about the repump and cooling transitions for the two elements here.
The sketch of a top view on our vacuum system shows its main components:
Two glass cells in two regions of vacuum are separated via a differential pumping stage. We collect Rubidium and Potassium atoms in the bigger glass cell on the left. Then we transport our atoms mechanically with moving magnetic coils to region with a much better vacuum, where we cool the atoms down to a few hundred Nanokelvin above absolute zero in a magnetic trap. Click here to watch a movie of our moving magnetic coils.
The two pictures show the MOT-cell on the left and the science cell on the right. Our setup allows us a very good optical access for further experiments on quantum degenerate gas mixtures. In the picture above, the harmonic magnetic trap was not installed. Here is a picture of the magnetic trap, three coils in the so called QUIC configuration:
To load our MOT efficiently we shine UV light on our glass cell to free atoms from the surface of the cell. On the left side, there is a picture of the glass cell illuminated by UV light (395nm) LED-arrays and on the right side a Rubidium-MOT after the UV light was shut off.
Of course, we have to cover the glass surface with Rubdium and Potassium atoms first. Therefore we fire Rb87 and enriched K40 Alkali-Dispensers for a few minutes and then operate our MOT by using LIAD only.
For more details, please read our publication, where we investigated LIAD for Potassium and Rubidium thoroughly (Phys. Rev. A 73, 013410 (2006)).
