Measurments of two-photon absorption and excited-state absorption in molten organic materials by the Z-scan technique

Delocalized π-electron organic molecules have been studied extensively for applications in photonics and optical limiting. Two-photon absorption (TEA) in these materials poses a limitation for photonics applications but is desirable in optical limiting. Nonlinear absorption can be enhanced at high intensities if the material also exhibits linear absorption from the two-photon excited state.