Multi-photon Absorption Induced Fluorescence of a Novel Compound

The linear and nonlinear fluorescence spectra of 5-(9-anthryl)-3-(4-nitrophenyl)-1-phenyl-2-pyrazoline (ANPP) have been studied in different polarity solvents. The linear fluorescence spectrum of ANPP has two emission bands originating from the anthryl and pyrazoline moieties of ANPP on excitation at 355nm, 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 λ/3 and λ/2 of the exciting wavelength. The similar spectrum structure indicates that the nonlinear and linear fluorescence originates from the same relaxation process.