Compression of high-energy ultrashort laser pulses through an argon-filled tapered planar waveguide

We propose a hollow tapered planar waveguide for compression of high-energy ultrashort laser pulses. Direct measurements suggest that it seems to find a very good trade-off among the energy throughput, the beam focusability, and the pulse compressibility. With a Ti:sapphire laser pulse of 12:0 mJ and 40 fs, our experiment produces an output pulse of 9:4 fs duration with energy 9:1 mJ (transverse magnetic mode) or 10:0 mJ (transverse electric mode) in argon, each exhibiting a nice spatial mode. To evaluate such a tapered waveguide, the linear wave propagation theory and the solution to its complex propagation constant are also presented.