MeV electron acceleration at 1  kHz with <10  mJ laser pulses

We demonstrate laser-driven acceleration of electrons to MeV-scale energies at 1 kHz repetition rate using <10  mJ pulses focused on near-critical density He and H2 gas jets. Using the H2 gas jet, electron acceleration to ∼0.5  MeV in ∼10  fC bunches was observed with laser pulse energy as low as 1.3 mJ. Increasing the pulse energy to 10 mJ, we measure ∼1  pC charge bunches with >1  MeV energy for both He and H2 gas jets.