Pulse compression with planar hollow waveguides: a pathway towards relativistic intensity with table- top lasers

We study in detail the compression of high-energy ultrashort laser pulses to the few-cycle regime in gas-filled planar hollow waveguides. In this scheme, the laser beam is guided in only one transverse dimension, whereas the other dimension is free to adjust, allowing scalability to high pulse energies. We report on various practical aspects of the planar hollow waveguide compression scheme and characterize the dependence of the performance of the method on several experimental parameters: (i) we evaluate different materials for the construction of planar waveguides; (ii) we investigate the dependence of the pulse duration on gas type and pressure; (iii) we measure the spatial intensity and phase; (iv) we characterize the pulse duration along the transverse beam direction; and (v) we investigate the focusability. An output pulse energy of 10.6mJ at a duration of 10.1 fs (FWHM) in the beam center after compression is demonstrated. A careful estimation reveals that the radiation should be focusable to a relativistic intensity exceeding 1019Wcm−2 in the few-cycle regime. The experimental results are supported by numerical modeling of nonlinear pulse propagation inside planar hollow waveguides. We discuss energy up-scalability exceeding the 100mJ level. 4 Author to whom any correspondence should be addressed. New Journal of Physics 12 (2010) 073015 1367-2630/10/073015+25$30.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft