Single-Particle Two-Photon Absorption Imaging and Enhancement Determination for Organic Nanoparticles

The lack of characterization regimes available for the rapid single particle assessment of two-photon (TPA) response in nanomaterials remains a critical barrier to nonlinear optical device development. This is particularly true of nonemissive species whose TPA must often be characterized in the bulk from a novel porphyrin dimer, which is known to exhibit both severe fluorescence quenching and two-photon cross section (TPACS) enhancement when assembled into macro-molecules. We present here the first reported use of fiber aperture near-field enhancement in TPA response. This assembly/characterization regime provides a fast and fully actualized method for the generation of low-scatter optical-limiting organic nanomaterials where domain size morphology control and TPA enhancement are all critical to application viability and unobservable via bulk measurements.