Quantum chemistry study on the third-order nonlinear optical properties of spirobifluorene derivatives

We investigate the electronic properties and dynamic second hyperpolarizabilities of spirobifluorene derivatives by using quantum chemistry calculations. We find that studied spirobifluorene derivatives exhibit both large second hyperpolarizability and excellent transparency. In addition, the second hyperpolarizabilities 〈γ(−2ω; ω, ω, 0)〉 and 〈γ(−ω; ω, 0, 0)〉 increase with raising the frequency of incident light, and the increasing extent of 〈γ(−2ω; ω, ω, 0)〉 is larger than that of 〈γ(−ω; ω, 0, 0)〉. Resonance enhancement observed results in a significant dispersion of the 〈γ〉 values in visible region. The effects of the basis sets and substituent group on the polarizability and second hyperpolarizability are also discussed respectively.