Nonlinear Dynamics of Tetraphenylporphyrin and Dithiaporphyrin and Their Diacids via Pulse Trains with ps/ns Subpulse Widths

The nonlinear optical absorption of tetraphenylporphyrin (H2TPP) and dithiaporphyrin (DSP) and their diacids (H4TPP2+ and H2DSP2+) via pulse trains was studied. The subpulse widths of pulse trains were set as 30 ps and 5 ns according to experimental work. The dynamical absorption of pulse trains was studied by solving a paraxial field equation together with rate equations. The Crank–Nicholson numerical method was employed in numerical computation. In the weak energy region, neutral complexes H2TPP and DSP show lower energy transmittances than their diacids H4TPP2+ and H2DSP2+. And DSP with S-atoms shows the lowest transmittance. In the strong energy region, the energy transmittances of diacid complexes declines sharply. Thus H4TPP2+ shows the lowest transmittance among all complexes.