Improved efficiency and divergence of intense high-order harmonics from carbon plasma

Abstract

We improve the efficiency and divergence of high-order harmonics from carbon plasma, which could be pumped with sub-mJ laser. This opens the possibility for high repetition rate experiments with intense attosecond pulses. IntroductionHigh-order harmonic generation (HHG) is a method to generate coherent sources of extreme ultraviolet (XUV) radiation, which has opened new frontiers in science by pushing ultrafast science to the attosecond domain [1]. Progress in attosecond science has revealed many new phenomena that have never been seen with femtosecond pulses. Clearly, the next frontier is to study nonlinear effects at the attosecond timescale and in the XUV. However, a problem with present-day attosecond pulses is that they are just too weak to induce measurable nonlinearities, which severely limits the application of this source. Since attosecond experiments require data accumulation, kHz repetition rate, isolated attosecond pulses with µJ energy will enable us to enter a completely new phase in attoscience.