Jefferson Lab in the News
Putting Free-Electron Lasers to Work
Rabi oscillation of electrons bound to shallow hydrogenic impurities in a GaAs crystal has been demonstrated with a free electron laser. Intense terahertz FEL irradiation promotes bound ground-state electrons to an excited state from which they can escape to the crystal's conduction band. The transition radiation induces Rabi oscillation between the two states. Where the electrons end up depends on the duration of the irradiation pulse and the Rabi oscillation frequency, which is proportional to the amplitude of the THz irradiation. Plotting the crystal's photoconductivity against pulse duration, for different irradiation intensities, exhibits damped Rabi oscillation. (Adapted from ref. 8.)