Applied Physics Seminar

Theoretical and experimental advances towards a Terahertz (THz) driven accelerator and X-ray source technology are presented. The necessary strong field THz pulses are generated with optical lasers via optical rectification and cascaded optical parametric amplification promising high optical-to-THz conversion efficiencies eventually approaching 10%. Employing accelerating frequencies two orders of magnitude higher than in conventional radio-frequency (RF) devices brings several fundamental advantages: field emission threshold for surface electric fields increases to the GV/m range, pulsed heating is strongly reduced, bunch compression to the sub-femtosecond regime at high peak currents and operation at kHz-repetition rates at room temperature. The result is a much more compact and lower cost accelerator technology tightly coupled to optical fields with intrinsic synchronization. Designs for relativistic electron guns and accelerators based on single-cycle and multi-cycle THz pulses are presented and first experimental results are discussed. Together with the implementation of an optical undulator the possibility of a completely laser driven compact Free-Electron Laser-like attosecond X-ray source arises.

More about the speaker: Franz Kärtner heads the Ultrafast Optics and X-rays Division at the Center for Free-Electron Laser Science at DESY, is Professor of Physics at University of Hamburg and Principal Investigator at Research Laboratory of Electronics, Massachusetts Institute of Technology. Prof. Kärtner received his education in Electrical Engineering from Technical University in Munich, Germany.  He held positions at ETH Zurich, Karlsruhe Institute of Technology and MIT. His research interests are in classical and quantum noise in electronic and photonic systems, ultrashort pulse generation, precision timing distribution, optical waveform synthesis, high-energy THz generation and acceleration and its applications to attosecond science and compact attosecond hard X-ray sources. He has authored or co-authored more than 300 peer-reviewed journal publications, four book chapters and holds or has applied for more than 30 patents. He is a fellow of the Optical Society of America and the Institute of Electrical and Electronic Engineers.