Synthesis and two-photon absorption properties of symmetrical chromophores derived from 2,3,5-trisubstituted quinoxaline units

A set of symmetrically substituted multibranched chromophores composed of three quinoxaline-based congeners has been synthesized and experimentally shown to possess strong and widely dispersed two-photon absorptivities in the visible to near-IR region under the irradiation of femtosecond and nanosecond laser pulses. The electronic properties of the central π bridges incorporated into the final structures are closely connected to the molecular two-photon activities of these model compounds. Effective optical-power attenuation and stabilization behaviors in the nanosecond time domain of these dye molecules were also investigated. The structural motif of these compounds provides a useful approach for the molecular design of strong two-photon absorbing material systems with the potential for quick-responsive and broadband optical-control related applications, particularly for long-duration laser pulses in the near-IR region.