The two-photon absorption and applications become the hot points in the recent photoelectronic material research field. The two-photon absorption materials can be applied to many fields such as up-conversion lasing, optical limiting, optical stabilization, three-dimension optical storage, three-dimension micro-machining, et al. Especially studies of optical power limiting have become more interesting to the research community because of the need for automatic protection of optical sensors against intense laser radiation. Here we report the observation of the TPA and optical power limiting property of a novel double conjugated molecule DSBDR1 in solution. The linear absorption spectral is observed using a scanning spectrophotometer. Using Nd:YAG laser pulse as exciting laser, the incident pulse energy and the transmitted pulse energy are respectively recorded by an energy meter. Then we obtain the nonlinear absorption coefficient of the novel double conjugated molecule in THF. Figures show that the molecule exhibts the large TPA cross-section and excellent optical limiting at 1064 nm. The nonlinear absorption mechanism of the novel organic compound is finally analyzed.
Two-photon absorption coefficients and the corresponding absorption cross sections of 5-(9-anthryl)-3-(4-nitrophenyl)- 1-phenyl-2-pyrazoline (ANPP) are obtained from intensity dependent transmission measurements. The linear and nonlinear fluorescence spectra of ANPP have been studied. The linear florescence spectrum of ANPP has two emission bands originating from the anthryl and pyrazoline moieties of ANPP on excitation at 355-nm, respectively. The nonlinear two- photon and three-photon fluorescence from these two moieties are observed simultaneously when ANPP is excited at 1064-nm due to the proximity of the absorption bands of these two moieties to (lambda) /3 and (lambda) /2 of the exciting wavelength. The similar spectra structure indicates that the nonlinear and linear fluorescence originates from the same relaxation process.