Within my doctoral project I enhanced the capacities of SwissFEL in two ways by using beam tilts, i.e., by imposing a correlation between the transverse and temporal coordinates of the electrons. The beam tilt can be generated with different methods, namely with an rf transverse deflector, with electromagnetic wakefields from passive structures, or by introducing dispersion to an energy-chirped beam. First, I demonstrated temporal FEL pulse shaping with tilted electron beams. A linearly tilted beam can generate one short pulse, and a quadratically tilted beam can produce two short pulses. Pulse durations down to the sub-fs range were measured, and the novel operation mode of two-color FEL pulses was demonstrated. Second, I expanded the electron and photon diagnostics capabilities of SwissFEL with a novel method. I employed the beam tilt, generated by a passive wakefield streaker located after the undulator, to measure the longitudinal phase space of the electron beam. By comparing lasing-enabled and lasing-disabled conditions, the FEL power profile is reconstructed. The merits of the approach, with respect to previously implemented solutions with active rf streaking, are cost-effectiveness and self-synchronization.
