We report direct nanoscale imaging of ultrafast plasmon in a gold dolmen nanostructure excited with the 7is laser pulses by combining the interferometric time-resolved technology with the three-photon photoemission el...We report direct nanoscale imaging of ultrafast plasmon in a gold dolmen nanostructure excited with the 7is laser pulses by combining the interferometric time-resolved technology with the three-photon photoemission electron microscopy （PEEM）. The interferometric time-resolved traces show that the plasmon mode beating pattern appears at the ends of the dimer slabs in the dolmen nanostructure as a result of coherent superposition of multiple localized surface plasmon modes induced by broad bandwidth of the ultrafast laser pulses. The PEEM measurement further discloses that in-phase of the oscillation field of two neighbor defects are surprisingly observed, which is attributed to the plasmon coupling between them. Furthermore, the control of the temporal delay between the pump and probe laser pluses could be utilized for manipulation of the near-field distribution. These findings deepen our understanding of ultrafast plasmon dynamics in a complex nanosystem.展开更多
We report the direct imaging of plasmon on the tips pulses and probing of ultrafast plasmon dynamics by of nano-prisms in a bowtie structure excited by 7 fs laser combining the pump-probe technology with three-photon ...We report the direct imaging of plasmon on the tips pulses and probing of ultrafast plasmon dynamics by of nano-prisms in a bowtie structure excited by 7 fs laser combining the pump-probe technology with three-photon photoemission electron microscopy. Different photoemission patterns induced by the plasmon effect are observed when the bowties are excited by s- and p-polarized femtosecond laser pulses. A series of images of the evolution of local surface plasmon modes on different tips of the bowtie are obtained by the time-resolved three-photon photoemission electron microscopy, and the result discloses that plasmon excitation is dominated by the interfer- ence of the pump and probe pulses within the first 13 fs of the delay time, and thereafter the individual plasmon starts to oscillate on its own characteristic resonant frequencies.展开更多
A surface femtosecond two-photon photoemission （2PPE） spectrometer devoted to the study of ultrafast excited electron dynamics and photochemical kinetics on metal and metal oxide surfaces has been constructed. Low e...A surface femtosecond two-photon photoemission （2PPE） spectrometer devoted to the study of ultrafast excited electron dynamics and photochemical kinetics on metal and metal oxide surfaces has been constructed. Low energy photoelectrons are measured using a hemispherical electron energy analyzer with an imaging detector that allows us to detect the energy and the angular distributions of the photoelectrons simultaneously. A Mach-Zehnder interferom- eter was built for the time-resolved 2PPE （TR-2PPE） measurement to study ultrafast surface excited electron dynamics, which was demonstrated on the Cu（111） surface. A scheme for measuring time-dependent 2PPE （TD-2PPE） spectra has also been developed for studies of surface photochemistry. This technique has been applied to a preliminary study on the photochemical kinetics on ethanol/TiO2（110）. We have also shown that the ultrafast dynamics of photoinduced surface excited resonances can be investigated in a reliable way by combining the TR-2PPE and TD-2PPE techniques.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2013CB922404the National Natural Science Foundation of China under Grant Nos 11474040,11474039,61605017 and 61575030the Project of Changchun Science and Technology Bureau under Grant No 14KP007
文摘We report direct nanoscale imaging of ultrafast plasmon in a gold dolmen nanostructure excited with the 7is laser pulses by combining the interferometric time-resolved technology with the three-photon photoemission electron microscopy （PEEM）. The interferometric time-resolved traces show that the plasmon mode beating pattern appears at the ends of the dimer slabs in the dolmen nanostructure as a result of coherent superposition of multiple localized surface plasmon modes induced by broad bandwidth of the ultrafast laser pulses. The PEEM measurement further discloses that in-phase of the oscillation field of two neighbor defects are surprisingly observed, which is attributed to the plasmon coupling between them. Furthermore, the control of the temporal delay between the pump and probe laser pluses could be utilized for manipulation of the near-field distribution. These findings deepen our understanding of ultrafast plasmon dynamics in a complex nanosystem.
基金Supported by the National Basic Research Program of China under Grant No 2013CB922404the National Natural Science Foundation of China under Grant Nos 11474040 11274053,11474039 and 61178022the Project under Grant No 14KP007
文摘We report the direct imaging of plasmon on the tips pulses and probing of ultrafast plasmon dynamics by of nano-prisms in a bowtie structure excited by 7 fs laser combining the pump-probe technology with three-photon photoemission electron microscopy. Different photoemission patterns induced by the plasmon effect are observed when the bowties are excited by s- and p-polarized femtosecond laser pulses. A series of images of the evolution of local surface plasmon modes on different tips of the bowtie are obtained by the time-resolved three-photon photoemission electron microscopy, and the result discloses that plasmon excitation is dominated by the interfer- ence of the pump and probe pulses within the first 13 fs of the delay time, and thereafter the individual plasmon starts to oscillate on its own characteristic resonant frequencies.
文摘A surface femtosecond two-photon photoemission （2PPE） spectrometer devoted to the study of ultrafast excited electron dynamics and photochemical kinetics on metal and metal oxide surfaces has been constructed. Low energy photoelectrons are measured using a hemispherical electron energy analyzer with an imaging detector that allows us to detect the energy and the angular distributions of the photoelectrons simultaneously. A Mach-Zehnder interferom- eter was built for the time-resolved 2PPE （TR-2PPE） measurement to study ultrafast surface excited electron dynamics, which was demonstrated on the Cu（111） surface. A scheme for measuring time-dependent 2PPE （TD-2PPE） spectra has also been developed for studies of surface photochemistry. This technique has been applied to a preliminary study on the photochemical kinetics on ethanol/TiO2（110）. We have also shown that the ultrafast dynamics of photoinduced surface excited resonances can be investigated in a reliable way by combining the TR-2PPE and TD-2PPE techniques.
