Phenylene Vinylene Platinum(II) Acetylides with Prodigious Two-Photon Absorption

The linear and nonlinear optical properties.. of a series of linear and cross-conjugated platinum(II) acetylide complexes that contain extended p-(phenylene vinylene) chromophores are reported. The complexes exhibit very high femtosecond two photon absorption (2PA) cross Section values (sigma(2) up to 10 000 GM), as measured by nonlinear transmission (NLT) and two-photon excited fluorescence (2PEF) methods. The large 2PA cross sections span a broad range of wavelengths, 570-810 nm, and they overlap with the triplet excited. state absorption. Spectral coincidence of high cross section 2PA and triplet absorption is a key feature giving rise to efficient dual-mode optical power limiting (OPL).