Nanophotonic on-chip electron acceleration

The electric field amplitude produced by a femtosecond laser provides a powerful method to swiftly accelerate electrons. To efficiently couple to free electrons, the laser-electron interaction must be phase-matched. Considering the regime of linear optics, this has been shown to be possible using the inverse Smith-Purcell effect, where a laser generates intense nearfields in a nanophotonic structure designed to match the electron's velocity [1,2]. Where conventional radiofrequency cavities are typically damage-limited to 100 MV/m and usually operate at 25 MV/m electric fields, dielectric laser accelerator structures have been shown to withstand almost 10 GV/m fields [3] - two orders of magnitude higher. This enables the electron accelerator on a chip [4], because its length can be equally reduced by two orders of magnitude: from meter-size to centimeter-size.