Journal Article

Electron phase-space control in photonic chip-based particle acceleration

Shiloh, R., Yousefi, P., Mittelbach, A., Illmer, J., Niedermayer, U., Chlouba, T., Schönenberger, N., Hommelhoff, P.

2021

Overview

Particle accelerators are essential tools in science, hospitals and industry 1 – 6 . Yet their costs and large footprint, ranging in length from metres to several kilometres, limit their use. The recently demonstrated nanophotonics-based acceleration of charged particles can reduce the cost and size of these accelerators by orders of magnitude 7 – 9 . In this approach, a carefully designed nanostructure transfers energy from laser light to the particles in a phase-synchronous manner, accelerating them. To accelerate particles to the megaelectronvolt range and beyond, with minimal particle loss 10 , 11 , the particle beam needs to be confined over extended distances, but the necessary control of the electron beam’s phase space has been elusive. Here we demonstrate complex electron phase-space control at optical frequencies in the 225-nanometre narrow channel of a silicon-based photonic nanostructure that is 77.7 micrometres long. In particular, we experimentally show alternating phase focusing 10 – 13 , a particle propagation scheme for minimal-loss transport that could, in principle, be arbitrarily long. We expect this work to enable megaelectronvolt electron-beam generation on a photonic chip, with potential for applications in radiotherapy and compact light sources 9 , and other forms of electron phase-space control resulting in narrow energy or zeptosecond-bunched beams 14 – 16 . In a tiny chip-based particle accelerator, phase-space control of the emerging electron beam demonstrates guiding over a length of nearly 80 micrometres and an indispensable prerequisite to electron acceleration to high energies.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 142/126 / 639/766/1130/2799 / 639/925/927/1021 / Charged particle acceleration / Charged particles / Design and construction / Electron beams / Humanities and Social Sciences / Lasers / multidisciplinary / Nanostructure / Particle acceleration / Particle accelerators / Particle beams / Particle physics / Photonics / Radiation therapy / S phase / Science / Science (multidisciplinary)