We present an analytical expression for the response of a two-level atom to a frequency-modulated optically coherent pulse train. The optical beam has sinusoidal frequency modulation and is chopped to have a square-wave envelope. We assume that the laser pulses are short compared with the atomic-decay time, the pulse-repetition time, and the modulation period. With this short-pulse assumption we are able to use a method similar to Temkin’s [J. Opt. Soc. Am. B 10, 830–839 (1993)] and solve the optical Bloch equations in closed form.
[Optical Society of America ]
James M. Supplee, Edward A. Whittaker, and Keith Andrew, "Response of a two-level atom to a frequency-modulated optically coherent pulse train," J. Opt. Soc. Am. B 15, 1833-1838 (1998)