The ultrashort pulse laser writing multi-layered data bits in fused silica for three-dimensional optical data storage through the mechanism of optical damage induced by multi-photon absorption is demonstrated.The 800 ...The ultrashort pulse laser writing multi-layered data bits in fused silica for three-dimensional optical data storage through the mechanism of optical damage induced by multi-photon absorption is demonstrated.The 800 nm,120 fs Ti:Sapphire laser beam is focused into cubic samples with a 0.65 NA commercial microscope objective.The size of the recorded bits can be smaller than 0.5 × 0.5 × 2.5μm as the laser pulse energy is lower than 300 nJ and the corresponding bit data storage density is 0.2 × 10^(12) Tbits/cm^(3).Due to the aberration produced by the mismatch of the refractive indices between the recording material and its immersion medium,the longitudinal size of the recorded bit increases and the contrast of the bit to surrounding uninfected zone decreases as the bit plane gets deeper.Hence a relatively lower storage density of 0.05 × 10^(12) Tbits/cm3 is realized.展开更多
By using scanning near-field optical microscopy in the femtosecond time-resolved pump-probe experiments, we have studied the time-resolved near-field spectroscopy of CdSe nanocluster films. The submicrometer space dep...By using scanning near-field optical microscopy in the femtosecond time-resolved pump-probe experiments, we have studied the time-resolved near-field spectroscopy of CdSe nanocluster films. The submicrometer space dependence of electron dynamics was observed, which is attributed to the non-uniform distributions of interstitial defects in the films.展开更多
Surface modified PbS nanocrystals were fabricated by a novel method and their ultrafast optical nonlinearity was studied by the femtosecond time-resolved optical Kerr effect.A large nonlinear effect(χ^((3))~5×10...Surface modified PbS nanocrystals were fabricated by a novel method and their ultrafast optical nonlinearity was studied by the femtosecond time-resolved optical Kerr effect.A large nonlinear effect(χ^((3))~5×10^(-12) esu)with a laser pulse limited response was observed.This may be attributed to the reduction of surface trapped electrons due to the surface modification.展开更多
The relaxation of optically excited carrier in C_(70) thin film fabricated by physical jet deposition was investigated by femtosecond pump-probe measurements.A transient decrease in transmission was observed indicatin...The relaxation of optically excited carrier in C_(70) thin film fabricated by physical jet deposition was investigated by femtosecond pump-probe measurements.A transient decrease in transmission was observed indicating induced absorption.In comparison to C_(60) thin film the initial response of C_(70) film is laser pulse limited and the long lived component has smaller magnitude.The third order optical nonlinear susceptibility of C_(70) thin film was determined to be χ^((3))=3.3×10^(-11) esu by femtosecond time-resolved optical Kerr effect.From the primarily pulse limited response the dephasing time of C_(70) thin film has been proved to be shorter than the laser pulse width.展开更多
基金Supported by National Kay Basic Research Special Foundation under Grant No.G1999075207National Natural Science Foundation of China under Grant Nos.19884001 and 19525412.
文摘The ultrashort pulse laser writing multi-layered data bits in fused silica for three-dimensional optical data storage through the mechanism of optical damage induced by multi-photon absorption is demonstrated.The 800 nm,120 fs Ti:Sapphire laser beam is focused into cubic samples with a 0.65 NA commercial microscope objective.The size of the recorded bits can be smaller than 0.5 × 0.5 × 2.5μm as the laser pulse energy is lower than 300 nJ and the corresponding bit data storage density is 0.2 × 10^(12) Tbits/cm^(3).Due to the aberration produced by the mismatch of the refractive indices between the recording material and its immersion medium,the longitudinal size of the recorded bit increases and the contrast of the bit to surrounding uninfected zone decreases as the bit plane gets deeper.Hence a relatively lower storage density of 0.05 × 10^(12) Tbits/cm3 is realized.
基金the National Natural Science Foundation of China under Grant Nos.19774002,and 19634030Doctoral Program Foundation of High Education.
文摘By using scanning near-field optical microscopy in the femtosecond time-resolved pump-probe experiments, we have studied the time-resolved near-field spectroscopy of CdSe nanocluster films. The submicrometer space dependence of electron dynamics was observed, which is attributed to the non-uniform distributions of interstitial defects in the films.
基金Supported by the National Natural Science Foundation of China under Grant No.19574001。
文摘Surface modified PbS nanocrystals were fabricated by a novel method and their ultrafast optical nonlinearity was studied by the femtosecond time-resolved optical Kerr effect.A large nonlinear effect(χ^((3))~5×10^(-12) esu)with a laser pulse limited response was observed.This may be attributed to the reduction of surface trapped electrons due to the surface modification.
基金Supported by the National Natural Science Foundation of China。
文摘The relaxation of optically excited carrier in C_(70) thin film fabricated by physical jet deposition was investigated by femtosecond pump-probe measurements.A transient decrease in transmission was observed indicating induced absorption.In comparison to C_(60) thin film the initial response of C_(70) film is laser pulse limited and the long lived component has smaller magnitude.The third order optical nonlinear susceptibility of C_(70) thin film was determined to be χ^((3))=3.3×10^(-11) esu by femtosecond time-resolved optical Kerr effect.From the primarily pulse limited response the dephasing time of C_(70) thin film has been proved to be shorter than the laser pulse width.
