Attosecond control of electron emission

Attosecond control of electron emission

We have demonstrated an asymmetric electron emission from atomic targets can be generated and controlled by combining an attosecond pulse train composed of both odd and even harmonics and a weak IR field. Electron wave-packets are formed by ionizing the atomic target with the attosecond pulse train in the presence of a relatively weak infrared fi eld. Consequently, a mix of energy-degenerate even and odd parity states is fed in the continuum by one- and two-photon transitions. These interfere, leading to an asymmetric electron emission along the polarization vector. We have shown that interference between one- and two-photon transitions produces a large asymmetry in the angular distribution of the photoelectrons. The direction of the emission can be controlled on an attosecond time scale by varying the time delay between the two pulses.

Left: Impact position on a 2D detector of photoelectrons emerging from an atomic target following absorption of attosecond pulse trains. Right: Asymmetry plot as function of the photoelectron energy and the time delay between the attosecond pulse and the IR field.

References:
G. Laurent et al. Physical Review letters 109, 083001 (2012)
G. Laurent et al. Journal of Physics: conference series 488, 012008 (2014)