Isolated attosecond pulses generated by relativistic effects in a wavelength-cubed focal volume

Lasers that provide an energy encompassed in a focal volume of a few cubic wavelengths (λ³) can create relativistic intensity with maximal gradients using minimal energy. With particle-in-cell simulations we found that single 200-as pulses could be produced efficiently in a λ³ laser pulse reflection by means of deflection and phase compression caused by the coherent motion of the plasma electrons that emit these pulses. This novel technique is efficient (∼10%) and can produce single attosecond pulses from the millijoule to the joule level.