  We report the flexible on-target delivery of 800 nm wavelength, 5 GW peak
power, 40 fs duration laser pulses through an evacuated and tightly coiled 10 m
long hollow-core nested anti-resonant fiber by positively chirping the input
pulses to compensate for the anomalous dispersion of the fiber.
Near-transform-limited output pulses with high beam quality and a guided peak
intensity of 3 PW/cm2 were achieved by suppressing plasma effects in the
residual gas by pre-pumping the fiber after evacuation. This appears to cause a
long-term removal of molecules from the fiber core. Identifying the fluence at
the fiber core-wall interface as the damage origin, we scaled the coupled
energy to 2.1 mJ using a short piece of larger-core fiber to obtain 20 GW at
the fiber output. This scheme can pave the way towards the integration of
anti-resonant fibers in mJ-level nonlinear optical experiments and laser-source
development.
