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 1.4-3.0mJ/cm². The throughputs of these complexes were limited to 0.31-1.13J/cm² for incident fluences as high as 3.5 J/cm². The limiting throughput was strongly influenced by the nature of the ligand. Lower bounds for the ratio of triplet 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.