Nanosecond reverse saturable absorption and optical limiting in (Me ₄N)₂[Cd(dmit)(Sph)₂]

We report the measurement of reverse saturable absorption and an optical limiting response in a new metallorganic material, (Me₄N) ₂[Cd(dmit)(Sph)₂], with nanosecond laser pulses at 532 nm. Pump-probe and open-aperture Z-scan techniques were used as mechanisms for an optical limiting response. The experimental results show that triplet-triplet absorption is responsible for measurable reverse saturable absorption at 532 nm, which results in optical limiting. The measured data can be simulated well by a rate-equation model, and thus the absorption cross section of the excited state can be evaluated.