Comparison between the optical limiting behavior of chloroaluminum phthalocyanine and a cyanine dyeOne of the key issues involved in the development of passive optical power limiters is the search for appropriate materials that show effective reverse saturable absorption. Metallo-phthalocyanines seem to be good candidates for such applications because of their high optical nonlinearity and their unique electronic absorption characteristics. A series of 1,4,8,11,15,18,22,25-octa-decyloxy metallo-phthalocyanines containing palladium, nickel, cobalt, copper, and zinc as central metal atoms were characterized for their nonlinear absorptive properties to evaluate their suitability to function as reverse saturable absorbers. Nonlinear transmission measurements were analyzed in terms of a five-state model and a simple model based on the effective excited-state absorption cross sections without ascribing their origin to the states involved. Optical limiting thresholds were also estimated and compared with the absorption cross sections.

One of the key issues involved in the development of passive optical power limiters is the search for appropriate materials that show effective reverse saturable absorption. metallophthalocyanines seem to be good candidates for such applications because of their higher optical nonlinearity and the unique electronic absorption characteristics. A series of 1 ,4,8, 1 1 ,15 ,18,22,25-octa-decyloxy metallophthalocyanines containing various central metal atoms such as zinc, copper, palladium, nickel, and cobalt were characterized for their nonlinear absorptive properties to evaluate their suitability to function as reverse saturable absorbers. Nonlinear transmission measurements were analyzed in terms of five-state model and magnitudes of the parameters of the model were determined.