POLARIZATION SPECTROSCOPY IN THE LIMIT OF STRONG SATURATION

Author Institution: Department of Chemistry, Princeton University; Department of Chemistry, Temple UniversityPolarization spectroscopy is one of the most sensitive methods of detection of Optical-Optical double resonance. It is based upon the differential population of the different M levels of the pumped state. As such one would expect that the strength of the signal would decrease in the limit of strong saturation. However, explicit solution of the coupled Maxwell-Block equations shows that if one has strong saturation and an optically thick sample, then one finds that as a result of pulse reshaping, the distribution of M level populations is even more strongly peaked than in the linear response limit, but of the opposite sense, i.e. for R branch lines the population peaks for $M-0.9$ J with a FWHM of only $\sim 0.25$ J."