The quantum dynamics of a two-level system illuminated by a few-cycle pulse with an adjustable carrier-envelope (C-E) phase is investigated theoretically. We consider the weak-field regime where tunneling processes and multiphoton ionization are negligible. It is shown that the upper state population exhibits a strong dependence on the C-E phase and on the time of arrival of the few-cycle pulse if the system is initially prepared in a coherent superposition state. We demonstrate that this effect can be employed to probe the coherence properties of the superposition state and allows one to determine the phase of the laser that prepares this state.
© 2009 Optical Society of America
Original Manuscript: March 26, 2009
Revised Manuscript: July 22, 2009
Manuscript Accepted: July 22, 2009
Published: September 16, 2009
Xiao-Tao Xie, Mihai Macovei, Martin Kiffner, and Christoph H. Keitel, "Probing quantum superposition states with few-cycle laser pulses," J. Opt. Soc. Am. B 26, 1912-1917 (2009)