Compression of intense ultrashort laser pulses in a gas-filled planar waveguide

We report on the compression of intense ultrashort laser pulses for the purpose of producing few-cycle optical pulses at the multimillijoule level by using a planar waveguide (PWG). The PWG is composed of two parallel glass slabs separated by a gap of 100 microm and mounted in a gas chamber filled with a noble gas. In comparison with the conventional hollow-fiber-based pulse compression technique, the use of a PWG enables the injection of high-energy ultrashort pulses, because the input laser beam is confined only in the lateral direction perpendicular to the waveguide plane. Using this technique, we demonstrate the generation of 12 fs, 2 mJ laser pulses in an argon-filled PWG.