Guiding of 35 TW laser pulses in ablative capillary discharge waveguides

An ablatively driven capillary discharge plasma waveguide has been used to demonstrate guiding of 30 fs, 35 TW laser pulses over distances up to 3 cm with incident intensity in excess of 4 × 10¹⁸ W/cm². The plasma density range over which good guiding was observed was 1-3 × 10¹⁸ cm^-3. The quality of the laser spot at the exit mode was observed to be similar to that at the entrance and the transmitted energy was ∼25% at input powers of 35 TW. The transmitted laser spectrum typically showed blueshifting due to ionization of carbon and hydrogen atoms in the capillary plasma by the high intensity laser pulse. The low plasma density regime in which these capillaries operate makes these devices attractive for use in single stage electron accelerators to multi-GeV energies driven by petawatt class laser systems.