ULTRAFAST OPTICAL-PROPERTIES OF C-70 THIN-FILM

The relaxation of optically excited carrier in C-70 thin film fabricat ed by physical jet deposition was investigated by femtosecond pump-pro be measurements. A transient decrease in transmission was observed ind icating induced absorption, In comparison to C-60 thin film the initia l response of C-70 film is laser pulse limited and the long lived comp onent has smaller magnitude. The third order optical nonlinear suscept ibility of C-70 thin film was determined to be chi((3)) = 3.3 x 10(-11 ) esu by femtosecond time-resolved optical Kerr effect. From the prima rily pulse limited response the dephasing time of C-70 thin film has b een proved to be shorter than the laser pulse width.