Why is a MOT required?

  1. Prerequisite of single-atom optical tweezer

Laser

  1. Cooler: red-detuned cyclic transition → Doppler cooling
  2. Repump: from dark state to cyclic transit state.

Laser cooling - Optical molasses (OM)

Magneto-optical trap (MOT)

$$ \omega_L' = \omega_L-\vec{k}\cdot \vec{v} $$

required detuning for cooling…