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

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.