Development of Novel Three- and Four-Photon-Absorption-Based Optical Power-Limiting Materials: Molecular Design, Synthesis and Characterization

In this two-year proposed research project, we aim to explore the molecular design strategies toward three- and four-photon absorbing (3PA/4PA) chromophores. Two correlative missions are involved in the proposed research: [1] Molecular design and synthesis of highly active 3PA/4PA dendritic structures; [2] Structure-nonlinear property relationship studies and optical power-limiting property characterizations.In order to explore the structural effects on the molecular nonlinear absorption behaviors, we intend to develop new pi-centers containing various fused heterocycles and utilize these coplanar cores to develop novel multi-branched frameworks that exhibit strong three- and four-photon properties.For the optical properties characterization, both wavelength-tunable nanosecond and femtosecond lasers will be invoked to probe multi-photon absorption and fluorescence properties within the spectral range of 700-2000 nm. The study of optical power limiting properties of the proposed materials is planned to be carried out for the model compounds with superior 3PA and 4PA. The results obtained from the proposed research are beneficial for understanding the relationship between molecular structure and 3PA/4PA properties. The detail works involved in this Proposal and the time-table to carry out the proposed research is described in detail in the text body of this Proposal.