Tin Phthalocyanine Nanoprobes with Symmetric Macrocyclic Structures: Nonlinear Dynamics of Pulse Trains with Tunable ps/ns Subpulse Widths and Enhanced Optical Limiting for MEMS Microdevices

Tin phthalocyanine (SnPc) nanoprobes with strong reverse saturable absorption (RSA) are extremely needed for photoacoustic (PA) molecular imaging. The optical properties and dynamics of SnPc nanoprobes by pulse trains were studied. During the propagating of pulse trains in SnPc, the electronic structure of SnPc is simplified to the five-state energy model. The pulse train contains 25 subpulses with space 13 ns, and the widths of subpulses were set as 3.5 ps, 35 ps, 350 ps, 3.5 ns, 10 ns, 20 ns, 35 ns and 100 ns, respectively. In this work, we solved two-dimensional paraxial field coupled with rate equations employing the Crank–Nicholson numerical method. The results reveal the unique optical properties and outstanding optical limiting (OL) effects of SnPc nanoprobes, indicating huge application potential as optical limiters, sensors and switches.