Optical limiting performances of asymmetric pentaazadentate porphyrin-like cadmium complexes

The optical limiting performances of seven asymmetric pentaazadentate porphyrin-like cadmium complexes have been measured at 532 nm with nanosecond pulses. In a f/38 geometry, with sample transmission of 0.51-0.80 in a 2 mm cell, the limiting thresholds for these complexes were 1.4-3.0 mJ/cm(2). The throughputs of these complexes were limited to 0.31-1.13 J/cm(2) for incident fluences as high as 3.5 J/cm(2). The limiting throughput was strongly influenced by the nature of the ligand. Lower bounds for the ratio of tripler excited-state to ground-state absorption cross sections have been estimated at 3.4-5.7. The lower limiting thresholds, lower limiting throughputs, as well as the ease of modification of the ligands, make these complexes promising candidates for optical power limiters. (C) 1998 American Institute of Physics.