Axially Modulated Plasma Waveguides.

We demonstrate two techniques for making periodically modulated plasma waveguides-one with sharp, stable voids as short as 50 μm with a period as small as 200 μm, and another which modulates the waveguide diameter with a corrugation period as short as 35 μm [1]. These features persist as the plasma expands for the full lifetime of the waveguide (>6 ns). The waveguides were made using the hydrodynamic shock method in a cluster jet using hydrogen, nitrogen, and argon. We demonstrate guided propagation at intensities up to 2×1017 W/cm2, limited by our laser energy currently available. This technique is useful for quasi-phase matching to allow efficient coupling of laser energy to acceleration of relativistic electrons or generation of coherent electromagnetic radiation at selected frequencies. [ABSTRACT FROM AUTHOR]