The optical-limiting performances for four pentaazadentate metal complexes in tetrahydrofuran have been measured at 532 nm for 35-ps pulses, in which reverse saturable absorption from the singlet–singlet excited states should be responsible for the limiting mechanism. The excited-state parameters are calculated according to a six-level model. The limiting threshold at <i>T</i>/<i>T</i><sub>0</sub> = 0.5. is 44 mJ/cm<sup>2</sup>, and the throughput is limited to 27 mJ/cm<sup>2</sup> as incident fluence reaches 0.35 J/cm<sup>2</sup> for carboxyl pentaazadentate cadmium. The limiting thresholds and the throughput values are strongly influenced by peripheral substituents and central metal ions of the complexes.
© 2001 Optical Society of America
Fengqi Guo, Wenfang Sun, Duoyuan Wang, Lizheng Zhao, Zhenzhong Lu, and Yuxin Nie, "Optical Limiting of Pentaazadentate Metal Complexes for Picosecond Pulses in Solution," Appl. Opt. 40, 1386-1388 (2001)