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Figure 1: a) Typical classical trajectory of an atomic collision showing the flux enhancement effect. The solid (dashed) line indicates the atom's trajectory while in the excited (ground) state.The incoming atom approaches from the right. The atom pair is excited at tex2html_wrap_inline1863 by the trap laser pulse and is accelerated by the attractive long-range potential. After spontaneous decay, it proceeds to tex2html_wrap_inline1865 , where it may be excited again by a probe laser pulse. The atom pair is then accelerated quickly into short range, where either RE or tex2html_wrap_inline1867 may occur, leading to trap loss. b) Molecular potential diagram for the same process.

Figure 2: Classical simulations of time-resolved collisions at tex2html_wrap_inline1869 K. The trap (probe) laser intensity and detuning are 15.2mW/cm tex2html_wrap_inline1871 (7W/cm tex2html_wrap_inline1871 ) and tex2html_wrap_inline1875 , respectively. The five curves are generated using the C tex2html_wrap_inline1877 coefficients and excited-state lifetimes for each of the Hund's case (c) attractive molecular states. Plotted is the probability for flux enhancement to take place as a function of collision time (i.e., time to travel from tex2html_wrap_inline1863 to tex2html_wrap_inline1865 .)


Figure: 3 (a) Timing of the trap and probe laser pulses for the experiment. The trap laser is on at low (3.8mW/cm tex2html_wrap_inline1871 ) intensity for 5 tex2html_wrap_inline1885 s. This is followed by a series of short (100ns), intense (15.2mW/cm tex2html_wrap_inline1871 ) trap pulses. The probe pulses are 100ns long and are peaked at time tex2html_wrap_inline1889 after the peak of each trap pulse. The entire pattern repeats every tex2html_wrap_inline1891 s. (b) tex2html_wrap_inline1893 plotted as a function of tex2html_wrap_inline1889 . The flux enhancement effect increases only after a delay of 200ns, indicating a minimum collision time of tex2html_wrap_inline1897 . It then drops off slowly, in reasonable agreement with the simulations (Figure 2.)

Steve Gensemer
Mon Dec 1 12:11:25 EST 1997