Nonlinear relativistic optics in the single-cycle, single-wavelength regime with kilohertz repetition rate

Summary form only given. Recently, we have shown that single milijoule pulses in the 10-fs regime (single cycle), focused to 1-/spl mu/m (single wavelength), can produce intensities greater than 10/sup 19/ W/cm/sup 2/ at kilohertz repetition rates. Because of their very short Rayleigh range (/spl sim/1 /spl mu/m) one might think that these pulses would have only limited applications. They would not be useful in electron acceleration, where longer interaction distances are necessary. If the laser numerical aperture (NA) is matched to the NA of a relativistic waveguide (determined by the laser power and the plasma frequency), single-mode propagation of the relativistic pulse over many Rayleigh ranges can be obtained, as in conventional waveguide optics. This is demonstrated by the following 2D PIC simulation of laser pulse matching with a plasma slab.