Degenerate two-/three-photon absorption and optical power-limiting properties in femtosecond regime of a multi-branched chromophore

The degenerate two- and three-photon absorption properties of a multi-branched chromophore were investigated in the femtosecond regime utilizing white-light continuum and nonlinear transmission techniques. The experimental results show that the studied multi-branched structure exhibits relatively strong and broad two- and three-photon absorption bands in the near infra-red (IR) region. It is demonstrated that a highly conjugated molecular structure based on a symmetrically substituted skeleton would possess promoted molecular nonlinear absorptivities within the studied spectral region. Both two- and three-photon absorption-based optical power-limiting properties in the femtosecond time domain of this model compound were also characterized. The results indicate that a multi-chromophoric structure with expanded pi-conjugation could be an effective multi-photon absorber and might be used as a single-component material system for quick-responsive and broadband optical-suppressing related applications, especially when under ultrashort laser pulses.