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Bright sources under the projection microscope: using an insulating crystal on a conductor as electron source

Abstract : The development of bright sources is allowing technological breakthroughs, especially in the field of microscopy. This requires a very advanced control and understanding of the emission mechanisms. For bright electron sources, a projection microscope with a field emission tip provides an interference image that corresponds to a holographic recording. Image reconstruction can be performed digitally to form a "real" image of the object. However, interference images can only be obtained with a bright source that is small: often, an ultra-thin tip of tungsten whose radius of curvature is of the order of 10nm. The contrast and ultimate resolution of this image-projecting microscope depend only on the size of the apparent source. Thus, a projection microscope can be used to characterize source brightness: for example, analyzing the interference contrast enables the size of the source to be estimated. Ultra-thin W tips are not the only way to obtain bright sources: field emission can also be achieved by applying voltages leading to a weak macroscopic electric field (< 1V /µm) to insulating micron crystals deposited on conductors with a large radius of curvature (> 10µm). Moreover, analyzing the holograms reveals the source size, and the brightness of these new emitters equals that of traditional field emission sources.
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Contributor : Evelyne Salançon Connect in order to contact the contributor
Submitted on : Wednesday, November 24, 2021 - 7:14:22 PM
Last modification on : Wednesday, March 16, 2022 - 3:52:24 AM
Long-term archiving on: : Friday, February 25, 2022 - 8:10:56 PM


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  • HAL Id : hal-03447783, version 1



L Lapena, D Bedrane, A Degiovanni, E. Salançon. Bright sources under the projection microscope: using an insulating crystal on a conductor as electron source. European Physical Journal: Applied Physics, 2022. ⟨hal-03447783⟩



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