Detection and control of motion of signle atoms or ions in an optical cavity

Using quantum coherence effects, we have developed a new technique of detection of motion of signle atoms or ions in an optical cavity. We have theoretically demonstrated that a three-level atom inside a cavity can act as an ultra-dispersive medium and the group velocity of light becomes ultraslow. If the atom is in motion, it causes a phase shift because of Fizeau effect due to dragging of light, which can be observed. It has been shown that the change of phase is extremely sensitive to probe detuning in vicinity of resonance frequency and is in the order of $10^{-9}$ even for speed of a few meter per seconds.