Fluorescent signals following radiation trapping switching off by a detuned coupling laser

The fluorescent peak following radiation trapping switching off by a detune d coupling laser was detected and analysed as a function of the laser detun ing, looking for maximum signal enhancement. The detected emission spectra consisted of two sidebands with different peak intensities and positions wi th respect to resonance. The asymmetric enhancement of the sideband next to resonance with respect to the detuning sign showed an amplification depend ence of the process on the asymmetric pump mechanism utilised, which was al most entirely hidden in the resonant case. The two sidebands could be fitte d only separately with the quasi-steady state transition probability functi on already used in the resonant case, showing the limits of the theoretical approach. (C) 1999 Elsevier Science B.V. All rights reserved.