Inverse design and demonstration of on-chip laser-driven particle accelerators (Conference Presentation)

We present the first demonstration of a waveguide-integrated dielectric laser accelerator. This structure and associated grating coupler are designed using a gradient-based inverse design approach. A waveguide is directly interfaced with an accelerator structure which is patterned with sub-wavelength features to produce near-fields phase-matched to electrons travelling through a 250 nm gap in the structure. We have experimentally demonstrated these waveguide-integrated accelerators by showing acceleration of subrelativistic electrons of initial energy 83.5 keV. We observe a maximum energy modulation of 1.19 keV over 30 μm. These results represent a significant step toward scalable and integrable on-chip dielectric laser accelerators for applications in ultrafast, medical, and high-energy technologies.