title: Determination of two-photon absorption cross sections of photosensitizers and its implications for two-photon polymerization.
abstract: We report two-photon absorption cross sections and two-photon excited fluorescence of the photosensitizer 4,4'-Bis(diethylamino)benzophenon and thioxanthone using a femtosecond laser delivering pulses of wavelength 800 nm and 150 fs duration at rates of 1 kHz. Values for the two-photon absorption cross section are derived by comparing the fluorescence signals excited by wavelengths of 800 and 400 nm using a second-harmonic generator. Fluorophore fluorescence intensities dependence with quadratic illumination laser power showed no significant deviation from the two-photon absorption process. Implications of these cross-section measurements for two-photon polymerization are discussed.
authors.forename: Bibi Safia
authors.initials: BS
authors.lastname: Haq
authors.forename: Hidayat Ullah
authors.initials: HU
authors.lastname: Khan
authors.forename: Khan
authors.initials: K
authors.lastname: Alam
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ajmal
authors.forename: Shehnaz
authors.initials: S
authors.lastname: Attaullah
authors.forename: Islam
authors.initials: I
authors.lastname: Zari