EFFECT OF LASER INTENSITY VARIATION AND COHERENCE ON THE RESONANT EXCITATION OF THE 6P-1(1)-6D-1(2) TRANSITION OF ATOMIC MERCURY

The effects of resonant laser excitation of an atomic transition whose lower state is not a ground state are reported. The system studied is the optical excitation to the 6(1)D2 state from the electron-excited 6(1)P1 state of Hg. Both the total fluorescence intensity and the time-resolved electron-photon coincidence fluorescence signal from the 6(1)D2-6(3)P1 relaxation channel are observed as the laser intensity is varied. In the coincidence signals, a manifestation of Rabi cycling in the optically excited transition is evident. The experimental data are in generally good agreement with predictions from a quantum-electrodynamic model.