SELECTIVE PHOTOIONIZATION OF YB-168 IN A 3-LEVEL ATOMIC MEDIUM BY THECOLLINEAR PROPAGATION OF LASER-PULSES

The medium of the three-level Yb atom corresponding to the three-colou r, three-step, three-photon scheme of 6(1)S(o) (0 cm(-1)) --> 6(3)P(1) (17992.008 cm(-1)) --> (7/2, 3/2)(2)4f(13)6s(2)6p (35 196.98 cm(-1)) --> autoionization state (52 353 cm(-1)) is chosen to examine the sele ctive photoionization of Yb-168. The Maxwell-Bloch equation is numeric ally solved, where the interacting laser pulses are supposed to be col linear and resonant with the transition lines of Yb-168, and the effec ts of Doppler broadening and laser bandwidth are incorporated. Firstly , the thin medium dynamics are examined to determine the optimal energ y of laser pulses for the selective photoionization of Yb-168, and to determine Yb isotopes which have a large influence on the excitation o f Yb-168. Secondly, the thick medium dynamics are investigated, result ing in the fact that the laser pulse for the first transition is promi nently deformed due to the near-resonant interaction with Yb-171 and Y b-173, and the ion yield along the propagation of the laser beam is st rongly dependent on the initial energy of pulse for the first transiti on and the time-delay between input pulses.