High power laser technology has been developing since its emergence, it has been widely used in various fields. Accordingly, to avoid eyes and devices from high-power laser damage, the research on laser protection has also been paid great attention. The optical limiting technology based on the principle of nonlinear optics is one of the important technical means to realize laser protection. However, few reports on the specific physical processes and related mechanisms of solvent molecules affect the optical limiting properties of metal phthalocyanine materials.

In a study published in Physica Scripta, a research group led by Prof. CHEN Fei and his student DU Xinchen from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) proposed the solvent-conjugation-induced ultrafast dynamics of enhanced reverse saturable absorption in lead phthalocyanine derivatives solutions.

The ultrafast dynamic mechanism of solvent molecules affecting the optical limiting of lead (II) tetrakis (4-cumyl phenol) phthalocyanine material is analyzed by Z-scan technology and steady-state and transient absorption spectroscopy.

From the analysis and discussion of Z-scan, steady-state and transient absorption spectra, we can get two results: first, with the increase of solution concentration, the excited state absorption cross-section, and effective two-photon absorption coefficient will increase, especially 4-PbPc/TOL. Second, the type of solvent molecules in the solution will also affect the optical limiting performance of phthalocyanine solution, we prove that the conjugation of solvent molecules will affect the efficiency of charge transfer.

The research will provide new ideas for the design of subsequent molecular structures, provide theoretical guidance and experimental clues for the exploration of materials with better optical limiting performance, and promote the further development of the field of laser protection.