Phase-dependent laser acceleration of electrons with symmetrically driven silicon dual pillar gratings

Abstract

We present the demonstration of phase-dependent laser acceleration and deflection of electrons using a symmetrically driven silicon dual pillar grating structure. We show that exciting an evanescent inverse Smith-Purcell mode on each side of a dual pillar grating can produce hyperbolic cosine acceleration and hyperbolic sine deflection modes, depending on the relative excitation phase of each side. Our devices accelerate sub-relativistic 99.0 keV kinetic energy electrons by 3.0 keV over a 15 μm distance with accelerating gradients of 200 MeV/m with 40 nJ, 300 fs, 1940 nm pulses from an optical parametric amplifier. These results represent a significant step towards making practical dielectric laser accelerators for ultrafast, medical, and high-energy applications.

On-chip integrated laser-driven particle accelerator

“…These structures, together with focusing elements, integrated electron sources, and microbunching structures, form the building blocks to achieve mega-electron volt-scale energy gain through cascaded stages of acceleration (10)(11)(12)(13). Previous demonstrations of DLAs have relied on free-space lasers directly incident on the accelerating structure, often pillars or gratings made of fused silica or silicon (14)(15)(16)(17)(18)(19)(20). However, free-space excitation requires bulky optics; therefore, integration with photonic circuits would enable increased scalability, robustness, and impact of this technology.…”

Laser-Driven Electron Lensing in Silicon Microstructures

“…The structure constant c s was measured to be 0.38 ± 0.04 for this structure, with a maximum acceleration gradient e 1 of 111 ± 6 MeV/m. Previous work with similar structures has demonstrated c s = 0.27 ± 0.03, with e 1 = 133 ± 8 MeV/m [20].…”

“…As in the main manuscript, we consider a dual-pillar structure semi-infinite in x, symmetric in y, and periodic in z (following [20][21][22]). The device is illuminated by two counter-propagating z-polarized plane waves, incident from the y direction.…”

“…In this letter, we demonstrate a laser-driven, solid-state electron lens based on the DLA architecture, which was first proposed by Plettner et al in [18,19], and whose specific architecture is discussed by Leedle et al in [20]. When illuminated by two laser pulses, each with an electric field of 100 ± 10 MV/m, its focal length is measured to be 50 ± 4 µm (B = 1.4 ± 0.1 MT/m).…”

Dielectric laser electron acceleration in a dual pillar grating with a distributed Bragg reflector

“…They also show a maximum amplitude for the acceleration mode by introducing half a period (λp/2) offset for one row of pillars with respect to the other. This offset is found to be ideal only for low electron energies whereas for higher energies of about 100 keV, dual pillar structures without an offset yield a better efficiency of excitation for the acceleration modes [18].…”