Measurement of Lorentzian linewidths by pulse propagation delay

Two related methods for determining the Lorentzian linewidth of one- and two-photon transitions in an atomic medium are presented. In each method, the linewidth is determined by the relationship between the energy transmission and propagation delay of a series of laser pulses sent through the medium; precise knowledge of the laser frequency, atom density, or matrix elements is not required. {} 1996 The American Physical Society.