The compact, repetitively pulsed HF chemical laser built 2 years ago has
been modified to increase the output laser energy. The discharge volume
is now 1.4 1 instead of 0.54 1 for the previous electric discharge. Due
to high voltage limitation, the discharge gap was only slightly
increased. The discharge width along the flow direction was increased
from 4 to 8 cm. To achieve an easily usable beam, a novel optical
configuration consisting of two passes with 2 folding mirrors has been
used. It gives a 35 X 35 mm2 square output beam. To date, a
maximum output laser energy up to 12 J per pulse was obtained at the HF
wavelength using C2H6 as the hydrogen donor. At DF
wavelength the energy per pulse was about 3 J using D2. In
repetitive operation, the repetition rate was limited to about 65 Hz due
to the available flow rate of the gas loop. The average power obtained
was 610 W.