Broadband Coherent Diffraction for Single-Shot Attosecond Imaging.

Recent advances in the field of attosecond science hold the promise of tracking electronic processes at the shortest space and time scales. Imaging methods that combine attosecond temporal with nanometer spatial resolution are currently out of reach. Coherent diffractive imaging is based on the diffraction by a sample of a quasi-monochromatic illumination with a coherence time that exceeds the duration of an attosecond pulse. Due to the extremely broad nature of attosecond spectra, novel imaging techniques are required. Here, we present an approach that enables coherent diffractive imaging with a broadband isolated attosecond source. The method is based on a numerical monochromatisation of the broadband diffraction pattern by the regularised inversion of a matrix which depends only on the spectrum of the diffracted radiation. Experimental validations in the visible and hard X-rays show the applicability of the method. Because of its generality and ease of implementation for single attosecond pulses we expect this method to find widespread applications in future attosecond technologies such as petahertz electronics, attosecond nanomagnetism or attosecond energy transfer.