Speaker
Description
We demonstrate the generation of both soft and hard X-ray attosecond pulses at SwissFEL, based on the temporal shaping of the photocathode laser pulses [1]. Through flexible bunch compression schemes, the electron beam current profile evolves from a double-Gaussian shape with 10 ps duration into a femtosecond-scale isolated high-current spike in the core of a tens-of-femtosecond-long electron bunch. This high-current spike enables the generation of isolated soft and hard X-ray pulses characterized by a single spectral spike with multi-eV bandwidth, consistent with attosecond pulse durations. High-resolution measurements of the electron beam longitudinal phase space, together with start-to-end simulations, provide further support for the attosecond-scale duration of the emitted X-ray pulses. In the soft X-ray regime, the polarization of the attosecond pulses can be continuously tuned from linear to circular using the APPLE-X undulator [2]. We further demonstrate rapid switching of the soft X-ray pulse duration from sub-femtosecond to tens of femtoseconds by exploiting the time-dependent transverse phase space of the shaped electron beam.
Z.G., H.Z. and C.B. acknowledge support from the Swiss National Science Foundation under grant number 197372. We acknowledge the Paul Scherrer Institute for provision of SwissFEL beamtime.
[1] Zhang, Z., et al, New Journal of Physics 22.8 (2020): 083030.
[2] Schmidt, T., and Calvi, M., Synchrotron Radiation News 31.3 (2018): 35-40.
| Scientific Topics | AMO Physics |
|---|