The JEOL JBX-5000LS is a vector type machine.The system hardware features an ion-pumped column,a LaB 6 electron emitter,25kV and 50kV accelerating voltage,and a turbo-pumped sample chamber.The resolution,stability,st...The JEOL JBX-5000LS is a vector type machine.The system hardware features an ion-pumped column,a LaB 6 electron emitter,25kV and 50kV accelerating voltage,and a turbo-pumped sample chamber.The resolution,stability,stitching and overlay of this system are evaluated.The system can write complex patterns at dimensions down to 30nm.The demonstrated overlay accuracy of this system is better than 40nm.展开更多
Spectrum analysis of the plasma has over the years been growing both in methods and instrument, which makes it become a widely used non-contact detection method, without disturbing the arc plasma itself. With noticeab...Spectrum analysis of the plasma has over the years been growing both in methods and instrument, which makes it become a widely used non-contact detection method, without disturbing the arc plasma itself. With noticeable developments in the industry application of the method, a need for careful analysis of the plasma with both time and space identification is desirable. Therefore, a spectral measurement system is developed in this paper for diagnosing arc plasma with time and space identification. With a new hollow probe scanning method, the instrument can be used to provide information like energy distribution of plasma, temperature within the arc plasma, which are of great significance with the requirement of space identification. Furthermore, the system can also be used to capture the instant state of the arc plasma with the synchronic triggering system, which uses high speed photo and electrical signal as the time criterion. The industry applications prove that the system works well for online detection of the arc plasma.展开更多
The electronic structure of methanol/TiO2（ll0） interface has been studied by photoemis- sion spectroscopy. The pronounced resonance which appears at 5.5 eV above the Fermi level in two-photon photoemission spectrosc...The electronic structure of methanol/TiO2（ll0） interface has been studied by photoemis- sion spectroscopy. The pronounced resonance which appears at 5.5 eV above the Fermi level in two-photon photoemission spectroscopy （2PPE） is associated with the photocatalyzed dissociation of methanol at fivefold coordinated Ti sites （Ti5c） on TiO2 （110） surface [Chem- ical Science 1, 575 （2010）]. To check whether this resonance signal arises from initial or intermediate states, photon energy dependent 2PPE and comparison between one-photon photoemission spectroscopy and 2PPE have been performed. Both results consistently sug- gest the resonance signal originates from the initially unoccupied intermediate states, i.e., excited states. Dispersion measurements suggest the excited state is localized. Time-resolved studies show the lifetime of the excited state is 24 fs. This work presents comprehensive char- acterization of the excited states on methanol/TiO2（110） interface, and provides elaborate experimental data for the development of theoretical methods in reproducing the excited states on TiO2 surfaces and interfaces.展开更多
基于超导原理的超导纳米线单光子探测器(superconducting nanowire single photon detector,SNSPD)以其在高量子效率、高计数率、低暗计数和低时间抖动等方面的优势引起广泛的研究。综述了SNSPD的物理模型和研究进展。首先从第一次在实...基于超导原理的超导纳米线单光子探测器(superconducting nanowire single photon detector,SNSPD)以其在高量子效率、高计数率、低暗计数和低时间抖动等方面的优势引起广泛的研究。综述了SNSPD的物理模型和研究进展。首先从第一次在实验上发现超导铅薄膜的电热效应出发讲述了SNSPD的起源。然后从SNSPD进行单光子探测的物理过程出发详细分析了SNSPD的单光子探测机制,并分别根据电热模型和唯象模型对探测机制进行了详细的物理解释。紧接着,详细阐述了量子效率分析模型,指出SNSPD的系统量子效率由本征量子效率、耦合效率和光吸收效率三部分组成。最后,从如何提高入射光子与SNSPD的耦合效率、如何提高光子吸收效率、如何提高SNSPD本征量子效率、研究基于新型材料的SNSPD、如何实现光子数分辨和对光子偏振态不敏感的SNSPD、以及研究SNSPD的噪声机制以减小暗计数和时间抖动等方面详细列举了目前各小组研究SNSPD所取得的最新进展。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
We present a time-resolved two-photon excitation fluorescence spectroscopy and a simultaneous time- and spectrum- resolved multifocal multiphoton microscopy system that is based on a high repetition rate picosecond st...We present a time-resolved two-photon excitation fluorescence spectroscopy and a simultaneous time- and spectrum- resolved multifocal multiphoton microscopy system that is based on a high repetition rate picosecond streak camera for providing time- and spectrum- resolved measurement and imaging in biomedicine. The performance of the system is tested and characterized by the fluorescence spectrum and lifetime analysis of several standard fluorescent dyes and their mixtures. Spectrum-resolved fluorescence lifetime images of fluorescence beads are obtained. Potential applications of the system include clinical diagnostics and cell biology etc.展开更多
文摘研究了光子数分辨探测器技术发展的物理基础,技术现状和发展趋势.重点分析了目前能达到单光子分辨的发展中的三种探测技术:越界超导传感技术(superconducting transition-edge sensor),电荷积分单光子探测技术(charge integration photon detection)和雪崩光电二极管单光子分布探测技术(delayed single photon probability mappingbased on avalanche photodiode),讨论了探测器的光子数分辨能力及其噪音来源.
文摘The JEOL JBX-5000LS is a vector type machine.The system hardware features an ion-pumped column,a LaB 6 electron emitter,25kV and 50kV accelerating voltage,and a turbo-pumped sample chamber.The resolution,stability,stitching and overlay of this system are evaluated.The system can write complex patterns at dimensions down to 30nm.The demonstrated overlay accuracy of this system is better than 40nm.
基金Research Project Supported by Shanxi Scholarship Council of China(No.2012-69)Selected Research Project by Department of Human Resources and Social Security of Shanxi
文摘Spectrum analysis of the plasma has over the years been growing both in methods and instrument, which makes it become a widely used non-contact detection method, without disturbing the arc plasma itself. With noticeable developments in the industry application of the method, a need for careful analysis of the plasma with both time and space identification is desirable. Therefore, a spectral measurement system is developed in this paper for diagnosing arc plasma with time and space identification. With a new hollow probe scanning method, the instrument can be used to provide information like energy distribution of plasma, temperature within the arc plasma, which are of great significance with the requirement of space identification. Furthermore, the system can also be used to capture the instant state of the arc plasma with the synchronic triggering system, which uses high speed photo and electrical signal as the time criterion. The industry applications prove that the system works well for online detection of the arc plasma.
文摘The electronic structure of methanol/TiO2（ll0） interface has been studied by photoemis- sion spectroscopy. The pronounced resonance which appears at 5.5 eV above the Fermi level in two-photon photoemission spectroscopy （2PPE） is associated with the photocatalyzed dissociation of methanol at fivefold coordinated Ti sites （Ti5c） on TiO2 （110） surface [Chem- ical Science 1, 575 （2010）]. To check whether this resonance signal arises from initial or intermediate states, photon energy dependent 2PPE and comparison between one-photon photoemission spectroscopy and 2PPE have been performed. Both results consistently sug- gest the resonance signal originates from the initially unoccupied intermediate states, i.e., excited states. Dispersion measurements suggest the excited state is localized. Time-resolved studies show the lifetime of the excited state is 24 fs. This work presents comprehensive char- acterization of the excited states on methanol/TiO2（110） interface, and provides elaborate experimental data for the development of theoretical methods in reproducing the excited states on TiO2 surfaces and interfaces.
文摘基于超导原理的超导纳米线单光子探测器(superconducting nanowire single photon detector,SNSPD)以其在高量子效率、高计数率、低暗计数和低时间抖动等方面的优势引起广泛的研究。综述了SNSPD的物理模型和研究进展。首先从第一次在实验上发现超导铅薄膜的电热效应出发讲述了SNSPD的起源。然后从SNSPD进行单光子探测的物理过程出发详细分析了SNSPD的单光子探测机制,并分别根据电热模型和唯象模型对探测机制进行了详细的物理解释。紧接着,详细阐述了量子效率分析模型,指出SNSPD的系统量子效率由本征量子效率、耦合效率和光吸收效率三部分组成。最后,从如何提高入射光子与SNSPD的耦合效率、如何提高光子吸收效率、如何提高SNSPD本征量子效率、研究基于新型材料的SNSPD、如何实现光子数分辨和对光子偏振态不敏感的SNSPD、以及研究SNSPD的噪声机制以减小暗计数和时间抖动等方面详细列举了目前各小组研究SNSPD所取得的最新进展。
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.
基金This work was supported by the National Natural Science Foun-dation of China (60627003, 60408011)Guangdong Natural Science Foundation (5010500)was also supported in part by Shenzhen Sci & Tech Program (200516).
文摘We present a time-resolved two-photon excitation fluorescence spectroscopy and a simultaneous time- and spectrum- resolved multifocal multiphoton microscopy system that is based on a high repetition rate picosecond streak camera for providing time- and spectrum- resolved measurement and imaging in biomedicine. The performance of the system is tested and characterized by the fluorescence spectrum and lifetime analysis of several standard fluorescent dyes and their mixtures. Spectrum-resolved fluorescence lifetime images of fluorescence beads are obtained. Potential applications of the system include clinical diagnostics and cell biology etc.
