Power broadening revisited: theory and experiment

The spectral width of an atomic absorption line, observed with a steady lig ht source, typically increases as the light intensity increases, an effect known as power broadening. In this paper, we point out classes of pulsed-li ght observations where power broadening does not always occur, We present a nalytical and numerical results, supported by experimental data of coherent pulsed excitation probed by photoionization, which show that the extent of power broadening depends crucially upon the nature of excitation and the t ype of measurement, In particular, we show that a spectral line obtained fr om measurement performed after pulsed excitation exhibits no power broadeni ng. For pulsed excitation and continuous measurement, the spectral line con tains two components: a power-broadened signal collected during the excitat ion and an unbroadened signal collected after the excitation. (C) 2001 Publ ished by Elsevier Science B.V.