High repetition rate sub-ns electron pulses from pulsed-resonance Rydberg field-ionization (PRRFI)

We demonstrate a novel technique, Pulsed-Resonance Rydberg Field-ionization (PRRFI), to generate low-energy electron bunches at high repetition rates. By combining continuous-wave laser excitation with a pulsed electric field, this method selectively ionizes Rydberg-Stark states in cesium atoms, producing sub-ns long electron bunches (down to similar to 100 ps) at a repetition rate of similar to 10 MHz. The method is demonstrated to offer significant advantages in terms of flexibility in the ionization repetition rate and pulse delay adjustments. The PRRFI method holds promises for applications in high-resolution electron microscopy and spectroscopy, potentially for overcoming the limitations of traditional electron sources in terms of brightness and energy spread.