EXCITED STATE ABSORPTION IN A SATURABLE ABSORBER

Abstract

Measurements carried out on chloroaluminum phthalocyanine under ruby laser excitation showed that the observed blue fluorescence originated in the second excited singlet state and was excited by transitions from the first excited singlet state. The upper limit of the excitation cross section of this transition was determined and shown to be without effect on the performance of this absorber as a passive Q switch. Two‐photon absorption in the chloronaphthalene solvent was also detected.