Abstract: Using few-state model and DFT method, we calculate the nonlinear optical properties of three Benzothiazolyl-derivatives newly synthesized. The calculation results show that when the delocalization of the p electrons in the organic molecules increases the maximum absorption take place red-shift. When the conjugate chain has a longer size, the distribution of the increasing size of the conjugate chain on the increasing cross section is more important than the changing of pull-electron base. This kind of molecule has a better TPA characteristic.

Key words: molecule photonics, two-photon absorption, density function theory, few-state model, hetero atomic ring molecules