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
Scientific Highlights
A novel terahertz source for selective phonon excitation
Excitation of coherent phonons using light is an emerging approach for investigating condensed matter physics. It has the potential not only to reveal the dynamics of collective lattice vibrations but also to tailor them for the ultrafast control over the electronic, magnetic, and structural properties in solids. The optical phonons, in most solids, lie primarily in the spectral region between 1 and 10 THz. Unlike conventional laser sources, coherent radiation at these frequencies allows us to study time-resolved lattice displacements with only minor deposition of heat or generation of hot electrons. However, the available high-field terahertz sources, with their quasi-single cycle temporal shape and broadband spectrum, cannot be used to excite the individual phonon modes. By contrast, the challenge of understanding the transient dynamics of low-energy excitations calls for novel sources of narrow-band terahertz radiation at high intensities that can be tuned to the individual phonon resonances. Moreover, with strong enough fields tuned precisely to a phonon resonance, non-linearities in the material can be targeted and potentially exploited.
Long-lived pionic helium: Exotic matter experimentally verified for the first time
Exotic atoms, in which electrons are replaced by other particles, allow deep insights into the quantum world. After eight years, an international group of scientists have succeeded in a challenging experiment conducted at PSI’s pion source: they created an artificial atom called “pionic helium”.
Tailored electron bunch for SwissFEL
In order to achieve high-brillance and ultra-short FEL pulses, a flat current profile of the electron bunch is required. We achieve this by temporal shaping of the photo-cathode laser. From a femtosecond Gaussian pulse, we produce a picosecond long, flat-top laser pulse. At low charge, the photo-cathode laser pulse temporal profile is directly transferred into the electron bunch temporal profile.