A Theoretical Study on the Nonlinear Optical Properties of Cyclophane and Its Derivatives

The density functional theory-based computational method is used to study the nonlinear optical properties of cyclophane and its derivatives and the possibility of their use for optical switch. According to the calculation results, the new molecules have a structure of inversion center symmetry in the absence of external electrical field applied and their first hyperpolaorizability is zero, corresponding to the "off" state of the optical switch. When the external electrical field is applied, the molecules convert to structures of non-inversion center symmetry and have large first hyperpolaorizabilities, corresponding to the "on" state of the optical switch. When the electric field strength is less than 1.39×10¹⁰ V/m, cyclophane and its derivatives exhibit good stability in both geometrical structure and electronic structure. Although there exists a small change of structural parameter for cyclophane derivatives caused by broken symmetry, it does not affect its structural stability. It is proved that cyclophane and its derivatives can be used for making nonlinear optical switch and a theoretical reference for nonlinear optical materiel design is provided.