Advances on Ultrafast Silicon Field Emitter Array Photocathodes for Coherent Radiation Sources Based on Inverse Compton Scattering

Low-cost, compact, and coherent X-rays sources would enable exciting applications such as biomedical imaging of soft tissue and real-time visualisation of molecules at a widespread scale. A promising approach to implement such an X-ray source is based on inverse Compton scattering of a series of nanostructured electron sheets accelerated to relativistic speeds. Photon-triggered field emission arrays can readily produce planar arrays of electron bunches with pC-level sheet charge at high repetition rates using intense laser pulses. In this article, the performance of single-crystal, ultrafast, photon-actuated silicon field emitter arrays is investigated for varying emitter height. Charge vs. incident photon pulse energy characteristics and quantum efficiency of the devices are reported