Laboratory for Non-linear Optics (LNO)
We develop and operate state-of-the-art laser systems for driving the high brightness electron source of the Hard X-ray Swiss Free Electron Laser (SwissFEL), and for pump-probe experiments at the photon-science beamlines. We improve and extend these systems according to the user requirements.
We pursue in-house research activities at the Hard X-ray Swiss Free Electron Laser (SwissFEL) and Swiss Light Source (SLS) beamlines exploiting LNO’s laser facilities. We perform R&D on laser-driven electron sources in close collaboration with PSI’s accelerator division.
Latest Scientific Highlights and News
In contrast to circular dichroism that is dependent on the polarization, helicoidal dichroism induced by a twisted wave front profile is scarcely known. The first evidence of magnetic helicoidal dichroism has now been observed in an experiment using Spiral Fresnel Zone Plates developed at the Paul Scherrer Institut.
SwissFEL is a compact, high-brilliance, soft and hard X-ray Free Electron Laser (FEL) facility laser composed of two parallel beam lines seeded by a common linear accelerator (LINAC), and a two-bunch photo-injector. For the injector, an innovative dual-photocathode laser scheme has been developed based on state-of-the-art Ytterbium femtosecond laser systems. We just published an overview of the the SwissFEL Photo Cathode Drive Lasers (PCDL) performance, pulse shaping capabilities as well as the versatility of the systems, which allow many different modes of operation of SwissFEL . The full control over the SwissFEL electron bunch properties via the unique architecture of the PCDL will enable in the future the advent of more advanced FEL modes; these modes are, but not restricted to, the generation of single or trains of sub-fs FEL pulses, multi-color FEL and finally the generation of fully coherent X-ray pulses via laser-based seeding.
A novel and noninvasive method for high-energy two-color x-ray FEL emission was demonstrated at SwissFEL. In the experiment, a laser emittance spoiler pulse is overlapped with the primary photocathode laser pulse to locally spoil the beam emittance and inhibit the FEL emission from the central part of the beam, ultimately resulting in X-ray emission at two wavelengths. High spectral stability and the possibility to independently control the duration and intensity ratio between the two-color X-ray pulses is demonstrated. The laser emittance spoiler also enables shot-to-shot selection between one and two-color FEL emission and further, as it does not contribute to beam losses, it is compatible with high repetition-rate FELs.
This article has been selected as the winner of the first Ernest Courant Outstanding Paper Recognition, a honor sponsored by the journal Physical Review Accelerators and Beams (PRAB) and the APS Division of Physics of Beams (DPB). This honor recognizes the most outstanding paper published in PRAB annually.