MOT stands for Magneto-Optical Trap. We use magnetic fields (magneto) and laser light (optical) to slow and trap Rubidium atoms at the center of  a glass cell (...trap). 

We used the ColdQuanta MiniMOT SE to trap Rubidium-85 atoms. Trapping requires locking our laser to the desired transition frequency, slightly red-detuned, which we achieved using a technique called Modulation Transfer Spectroscopy. We also had to manipulate our optics to ensure the beams at the trap were aligned, balanced, and correctly polarized.