Nonlinear Absorption Study Of A New Porphyrin Ramification (9, 9-bis (2-ethylhexyl)-2, 7-fluorene Ethynylene) (FE)

Materials which has large two-photon absorption cross-section have been investigated extensively for their potential applications such as optical limiting devices, upconverted lasers, stabilization, three-dimensional optical data storage, three-dimensional microfabrication, and two-photon induced fluorescence microscopy. To search and synthesize strong TPA molecule material is one of the hottest parts of material study field.In this dissertation, pump-probe experiment is used to test nonlinear absorption of a new organic material (9, 9-bis (2-ethylhexyl)-2, 7-fluorene ethynylene) (FE) at 680nm. Under the condition of picosecond, we can see that the absorption is very large and it is mainly from two photon absorption and excited-state absorption. The new organic material has very large TPA cross-section. So it is a very good TPA material.In theory, the three rate equation model is used to fit the experiment data. And the theoretical result fits well with the experiment data. Several optical-physics parameters of the porphyrin, especially the TPA cross-section of it is obtained. The TPA cross-section is very larger, it can get 6720GM.