Efficient Continuous-Wave Two-Photon Absorption in para-Phenylene-Type Polymers

Two-photon materials—in particular those with well-defined two-photon absorption (2PA) with a high 2PA cross section—have potential applications in three-dimensional data storage, for example. The 2PA cross section of ladder-type poly(p-phenylene) is found here to be one of the highest reported for organic materials. Concentration- and temperature-dependent measurements show that the absorption is a purely intra-chain process and that the effective conjugation length has an important impact on the 2PA cross section—in accordance with theory.