Optical limiting behavior of octa-decyloxy metallo-phthalocyanines

One of the key issues involved in the development of passive optical power limiters is the search for appropriate materials that show effective revers e 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, cob alt, copper, and zinc as central metal atoms were characterized for their n onlinear absorptive properties to evaluate their suitability to function as reverse saturable absorbers. Nonlinear transmission measurements were anal yzed in terms of a five-state model and a simple model based on the effecti ve excited-state absorption cross sections without ascribing their origin t o the states involved. Optical limiting thresholds were also estimated and compared with the absorption cross sections. (C) 2001 American Institute of Physics.