Optical properties of aminophenoxy substituted phthalocyanines and covalent linkage conjugates to cadmium telluride quantum dots interacting with picosecond pulse trains

We investigated nonlinear optical dynamics of asymmetric benzothiazole substituted phthalocyanines and their covalent attachments to glutathione functionalized cadmium telluride quantum dots (CdTe QDs) interaction with picosecond pulse trains. A pulse train with 50 subpulses of 100 picosecond width which was separated by 12 nanosecond spacing was employed as the laser source. A generalized five-level model was adopted to retrench the studied materials. In our simulation, we solved two-dimensional paraxial field equation entangled with the rate equations by Crank–Nicholson numerical method. Interacting with long pulse trains, the principal absorption channel in substituted phthalocyanines and their covalent attachments is the two-step two-photon absorption (TPA). All materials show excellent optical limiting behaviours and the results indicated that the covalent attachments of phthalocyanines to CdTe QDs are much better than phthalocyanines with long pulse trains.