Spatio-temporal coupling controlled laser for electron acceleration

Limited by the difficulty in acceleration synchronization, it has been a long-term challenge for on-chip dielectric laser-based accelerators to bridge the gap between non-relativistic and relativistic regimes. Here, we propose a laser-based accelerators based on a spatio-temporal coupling controlled laser pulse, which enables the acceleration of a non-relativistic electron to a sub-MeV level in a single acceleration structure (chirped spatial grating). It provides high precision temporal and spatial tuning of the driving laser via dispersion manipulation, leading to a synchronous acceleration of the velocity increasing electrons over a large energy range. Additionally, the spatio-temporal coupling scheme is a general method and can be extended to driving fields of other wavelengths such as terahertz pulses. Our results bring possibilities to MeV-scale portable electron sources and table-top acceleration experiments.