Selective photoionization of 168Yb in a three-level atomic medium by the collinear propagation of laser pulses

Abstract

The medium of the three-level Yb atom corresponding to the three-colour, three-step, three-photon scheme of 61S0 (0 cm-1) to 63P1 (17992008 cm-1) to (7/2, 3/2)24f136s26p (35196.98 cm-1) to autoionization state (52353 cm-1) is chosen to examine the selective photoionization of 168Yb. The Maxwell-Bloch equation is numerically solved, where the interacting laser pulses are supposed to be collinear and resonant with the transition lines of 168Yb, and the effects of Doppler broadening and laser bandwidth are incorporated. Firstly, the thin medium dynamics are examined to determine the optimal energy of laser pulses for the selective photoionization of 168Yb, and to determine Yb isotopes which have a large influence on the excitation of 168Yb. Secondly, the thick medium dynamics are investigated, resulting in the fact that the laser pulse for the first transition is prominently deformed due to the near-resonant interaction with 171Yb and 173Yb, and the ion yield along the propagation of the laser beam is strongly dependent on the initial energy of pulse for the first transition and the time-delay between input pulses.