Sodium MOT collection efficiency as a function of the trapping and repumping laser frequencies and intensities

Abstract

A detailed theoretical and experimental description of a sodium MOT as a function of the\ud pumping and repumping laser frequencies and intensities is given. The eective trapping schemes and the\ud collection eciency have been experimentally measured and calculated by solving an original 3D model.\ud This model considers the whole bunch of the 32 ground and excited (P1=2 + P3=2) Zeeman sublevels,\ud the actual trap geometry, the magnetic eld intensity and direction, the light polarization, and evaluates\ud both the velocity capture range vc and the number of trapped particles N. Synergetic and competition\ud mechanisms due to the trapping and repumping lasers have been predicted and experimentally observed.\ud The model simulation has been compared with the results reported in the literature and with those obtained\ud by us and a quite good agreement has been found. The model can be easily adapted to the other sodium\ud isotopes as well as to all the other alkalis

Long-term drift laser frequency stabilization using purely optical reference

“…As also reported in [6], at the high-frequency side the trap abruptly disappears. In our observation we were able to keep the trap unstable on that condition, with a fluorescence signal significantly lower than the maximum, and essentially stable in time.…”

“…Fig. 5 reports the saturation spectroscopy signal obtained by scanning the laser frequency over the D 2 , F g = 2 → F e = 1, 2, 3 lines of sodium [6]. Two traces of the same signal are also reported as obtained by keeping the frequency at a nominal fixed value, either with the stabilization system on or off.…”

Magneto-optical trapping forces for atoms and molecules with complex level structures

“…Its gradient is the square of the trapping frequency, ω , z 2 and this is found to be independent of g l . In 1D MOT theory, the trapping frequency is given by equation (6). The actual value of ω z is reduced because of the effects of the orthogonal beams, but the numerical model shows that its dependence on δ , 0 s, and g A u follows closely this standard expression.…”

“…Atomic MOTs where the cooling transition has ⩽ F F u l are also sometimes used [2][3][4][5][6][7]. Examples are MOTs working on the − S P 2 1 2 2 1 2 D 1 transition of alkali atoms.…”

Three-dimensional Doppler, polarization-gradient, and magneto-optical forces for atoms and molecules with dark states

“…In this case, atoms can be optically pumped into a dark state and uncouple from the light, and so these dark states must be destabilized [18] if the cooling is to be effective. Type-II MOTs have been studied experimentally [2,[19][20][21][22][23][24]. Compared to type-I MOTs, they tend to have higher temperatures, typically in the 2-20 mK range, larger cloud sizes, typically a few millimetres, and lower densities.…”