The Nonlinear Optical Properties Of Fuorenyl-based Chromophores

Nonlinear optics, as a fruitful and interesting branch in optics, emerged soon after the operation of the first ruby laser. Many scientists are working for nonlinear measurement techniques and nonlinear optical materials. In my paper, we research Fuorenyl-based chromophores, which is an important class of blue light-emitting polymer material. There have wide energy gap, high luminous efficiency and good molecular functionalities. So these can been widely used in flat panel display (PLEDs), solar cells, biological and chemical sensors. We choose two of Fuorenyl-based chromophores, and research their nonlinear features. The main research works are listed below:The nonlinear mechansim of Fuorenyl-based chromophores is determined by using time-resolved pump-probe technique. We found that adopted energy-level model of two-photon absorption induced excited stated absorption to explain the experimental results well. Due to the Fuorenyl-based chromophore obtain symmetrical molecule structure, which have the ability of push (pull) electron. This structure is helpful for delocalized electron to accompany with the electric field of the input laser beam, so they always have large two-photon nonlinear optic parameters. In addition, the chromophore has been studied by using optical power limiting experiment. The result indicated that the molecule has good optical power limiting property.As one of the first disussed nonlinear optical mechanisms, thermal effect is always existent when the laser pulses propagate through nonlinear optical materials. In paper, we have been discussed the transient thermally induced nonlinear characteristics of the liquor by using PO Z-scan technique. Finally, we discovered the relation of physical parameters and Z-scan curve. At the same time, the different mechansims could alter Z-scan curve figure. In addition, investigation of the temperature dynamics process in the liquor of Fuorenyl-based chromophore by using correlation Z-scan technique under ns laser pulse excitation. Afterwards we achieve physical parameters. Then based on the numerical calculation, we achieved the spatial and temporal changes of temperature.