Cross sections for excited-state absorption in a Pt:ethynyl complex

We report an experimental investigation to map out the spectral dependence of excited-state absorption in a Pt:ethynyl complex. The cross section for triplet state absorption (T1→T*),σT, was found to peak with a value of σT∼2.2×10-16 cm2 at 600 nm. The shape of this absorption peak was found to be the same for excitation at 355 and 532 nm, further supporting our interpretation of the electronic properties of the molecule. Broadband limiting against visible, nanosecond pulses was observed in an optical limiting test-bed.