Integrating the advances made in photonics with efficient electron emitters can result in the development of next generation photocathodes for various accelerator applications. In such photonics-integrated photocathodes, light can be directed using waveguides and other photonic components on the substrate underneath a thin (<100 nm) photoemissive film to generate electron emission from specific locations at sub-micron scales and at specific times at 100 femtosecond scales along with triggering novel photoemission mechanisms resulting in brighter electron beams and enabling unprecedented spatio-temporal shaping of the emitted electrons. In this work we have demonstrated photoemission confined in the transverse direction using a nanofabricated Si3N4 waveguide under a ∼20 nm thick cesium antimonide (Cs3Sb) photoemissive film. This work demonstrates a proof of principle feasibility of such photonics-integrated photocathodes and paves the way to integrate the advances in the field of photonics and nanofabrication with photocathodes to develop next-generation high-brightness electron sources for various accelerator applications.

Nanostructured electron sources exhibiting simultaneous spatio-temporal confinement to nanometer and femtosecond level along with a low emittance can be used for developing future ordered electron sources to generate unprecedented electron beam brightness and can revolutionize stroboscopic ultrafast electron scattering and steady-state electron microscopy applications. In addition, high current density electron beams generated from nanostructured electron sources can be used for applications that include nanoelectronics and dielectric laser accelerators. In this work, we report our efforts to develop and characterize two kinds of nanostructured electron sources: (i) nitrogen incorporated ultrananocrystalline diamond [(N)UNCD] tips and (ii) plasmonic Archimedean spiral focusing lens. We demonstrate the ability to fabricate these cathodes and characterize them using a photoemission electron microscope under femtosecond laser illumination thereby demonstrating the ability of these structures to be used for next generation electron sources.

Integrating the advances made in photonics with efficient electron emitters can result in the development of next generation photocathodes for various accelerator applications. In such photonics-integrated photocathodes, light can be directed using waveguides and other photonic components on the substrate underneath a thin (<100 nm) photoemissive film to generate electron emission from specific locations at sub-micron scales and at specific times at 100 femtosecond scales along with triggering novel photoemission mechanisms resulting in brighter electron beams and enabling unprecedented spatio-temporal shaping of the emitted electrons. In this work we have demonstrated photoemission confined in the transverse direction using a nanofabricated Si3N4 waveguide under a ∼20 nm thick cesium antimonide (Cs3Sb) photoemissive film. This work demonstrates a proof of principle feasibility of such photonics-integrated photocathodes and paves the way to integrate the advances in the field of photonics and nanofabrication with photocathodes to develop next-generation high-brightness electron sources for various accelerator applications.