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Ultrafast electron pulses, combined with laser-pump and electron-probe technologies, allow for various forms of ultrafast microscopy and spectroscopy to elucidate otherwise challenging to observe physical and chemical transitions. However, the pursuit of simultaneous ultimate spatial and temporal resolution has been largely subdued by the low monochromaticity of the electron pulses and their poor...
Needle-like single crystal diamond structures were obtained by combination of the plasma enhanced chemical vapor deposition (CVD) and selective oxidation techniques. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and the intensity of the femtosecond laser focused on the needle. Moreover, a new set-up based...
We present experimental results on laser-induced photoemission from nanotips made of different materials, and we compare photoemission from a metal surface (tungsten) to a dielectric (diamond). Ultrashort laser pulses (15–300 fs) are used to trigger electron emission from nanotips with radii < 100nm under a moderate tip bias. We show how different laser parameters as the repetition rate, the mean...
We describe the development of a micrometer-scale photoelectron gun for the implementation of ultrafast low-energy electron diffraction from surfaces. A photolithography process and focused-ion-beam nanostructuring is used to assemble and electrically contact the electron gun, which consists of a nanotip photocathode and an Einzel lens for beam collimation. First time-resolved measurements in a backscattering...
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