Dependence of Ramsey fringe width on parameters

A Ramsey pulse pair (two coherent pulses separated in time) clearly has much longer duration than either pulse would have by itself. This gives the Ramsey pair a narrower energy spectrum than the single pulse and therefore a fundamental spectroscopic advantage in resolution. Even if one uses a single ``long-type'' pulse (duration equal to that of the entire Ramsey pair including dark time) instead, the Ramsey pair spectrum can still be narrower. Under a broad range of circumstances, the central peak of the Ramsey pair's spectrum is only about 0.6 times as broad as that of a single long-type pulse. This ``narrowing factor'' of 0.6 does not always carry over directly to a comparison of peak widths as measured by population inversion. We will present results of calculations that explore how this narrowing factor (Ramsey versus single long-type pulse) depends on parameters such as pulse duration, dark time, and atomic inversion.