Laser-Based Acceleration of Nonrelativistic Electrons at a Dielectric Structure

A proof-of-principle experiment demonstrating dielectric laser acceleration of nonrelativistic electrons in the vicinity of a fused-silica grating is reported. The grating structure is utilized to generate an electromagnetic surface wave that travels synchronously with and efficiently imparts momentum on 28 keV electrons. We observe a maximum acceleration gradient of $25\text{ }\text{ }\mathrm{MeV}/\mathrm{m}$. We investigate in detail the parameter dependencies and find excellent agreement with numerical simulations. With the availability of compact and efficient fiber laser technology, these findings may pave the way towards an all-optical compact particle accelerator. This work also represents the demonstration of the inverse Smith-Purcell effect in the optical regime.