The effect of excited-state absorption-induced thermal refraction on the optical nonlinear refraction of ZnPc/DMSO solution

摘要

The optical nonlinearity of phthalocyanine zinc dissolved in dimethyl sulfoxide was investigated using a Z-scan technique. The sample demonstrated strong reverse saturable absorption and an overall self-focusing effect. The physical mechanism of nonlinear refraction was attributed to the competition between excited-state refraction and excited-state absorption-induced thermal refraction. The effect of excited-state absorption-induced thermal refraction on the nonlinear refraction of the sample was described and analysed in a transient regime as the input energy varied.