Spectral phase interferometry for complete reconstruction of attosecond pulses

We propose two methods for measuring the complete phase and amplitude of attosecond X-ray pulses produced by high harmonic generation in an atomic gas. These methods are based on spectral shearing interferometry and are achieved by pumping the harmonic source with two spectrally sheared driving pulses. This can be achieved in two configurations: either by having a time delay between the two driving pulses or by separating them spatially in the generation region. We show by numerical simulation that both these techniques are capable of retrieving full field information of the attosecond pulses produced and discuss their experimental implementation.