Nonlinear optical effects related to saturable and reverse saturable absorption by subphthalocyanines at 532 nm

Chem Commun (Camb). 2005 Aug 14:(30):3796-8. doi: 10.1039/b502359a. Epub 2005 Jul 4.

Abstract

It is found that both effects of saturable absorption and reverse saturable absorption are obtained with a solution of subphthalocyanine at 532 nm depending on the intensity of 9 ns laser pulses; saturable absorption occurs at lower intensity levels whereas the reverse effect prevails at higher levels; contrary to expectations, subphthalocyanines can behave as reverse saturable absorbers at 532 nm, despite the high linear absorption at this wavelength; data have been fitted with a five-level model which considers three consecutive electronic transitions with absorption cross-section values of 1.4 x 10(-16), 1.0 x 10(-16) and 40 x 10(-16) cm(2), respectively.