Nonlinear Optical Properties Of Two New Fluorene Derivatives

Since the appearance of laser in the early 1960s, nonlinear optics has been developed greatly. It is a new subject between basic subjects and applying subjects. With the deep investigation of theory and application, nonlinear optics has been applied in many fields.People have made the principle of nonlinear optics phenomenon clear through a long basic and practice research, so they begin to look for or synthesize new nonlinear optics materials providing with specific functions. Ideal optical materials provide with big nonlinear polarizability, small power threshold and quick response speed. A great deal of researches have indicated that organic compounds is promising nonlinear optical materials, since they can be synthesized with strongπelectron conjugated systems and electron transition between ligands and central atoms, which result in enhancement of nonlinear polarizability. Exploring organic compounds'characters and researching their optical properties are significant, which can direct us to synthesize more valuable organic compounds for practical applications in nonlinear optics.The principal work in this paper is to investigate the third-order and fifth-order nonlinear optical properties of two fluorene derivatives, which are named as 4-(2-(7- (4-aminostyryl)-9,9-bis(2-ethylhexyl)-9H-fluoren-2-yl)vinyl)benzenamino (abbrevi- ated as BASF) and 2,7-bis(4-methoxystyryl)-9,9-bis(2-ethylhexyl)-9H-fluorene (abb- reviated as BMOSF), and try to further perceive what mostly affects or determine their nonlinear optical characters in the molecule structure, in order to provide references for synthesizing better nonlinear optical materials in the future.Firstly, ps pulse laser is used to investigate the nonlinear absorption and upconversion radiation properties. Strong three-photon absorption frequence upconversion fluorescence emission is found. The three-photon absorption(3PA)...