PHOTON SCIENCE

The THz undulator beamline has been designed to provide coherent femtosecond (fs) – picosecond (ps) THz pulses for pump-and-probe experiments with the fs VUV pulses from FLASH. First light has been delivered into the FLASH experimental hall 'Albert Einstein' in November 2007. The THz pulses are generated by a purpose built undulator implemented in series to the VUV undulators. The design of the beamline allows to overlap a VUV pulse and a THz pulse generated by the same electron bunch at the end of BL3. The pulses should therefore be naturally synchronized. The expected pulse energies lie within the microjoule regime.

  THz radiation with the following parameters is available for pump-and-probe experiments at BL3:

• tunable: 10 ‐ 300 μm; up to 100 μJ/pulse; ~10% bandwidth,
• broadband at 200 μm; up to 10μJ/pulse; ~100% bandwidth
• synchronized and phase stable to X-­ray pulses (down to 5 fs)
• delivered to the experiment via vacuum beamline as:
• (i) ultra-­‐high vacuum (~10^­‐8 mbar), shorter delay between THz and X-­‐ray (~4 m path difference), can accommodate up to 0.3 m wide setup;
• (ii) high vacuum (pressure ~10^­‐6 mbar), longer delay between THz and X-­‐ray (~7 m path difference); can accommodate up to 2 m wide setup

Publications:

• Tim Oelze, Olena Kulyk, Bernd Schütte, Ulrike Frühling, Eva Klimešová, Bartholomäus Jagielski, Laura Dittrich, Markus Drescher, Rui Pan, Nikola Stojanovic, Vitaly Polovinkin, Krishna P. Khakurel, Kerstin Muehlig, Ivette J. Bermudez Macias, Stefan Düsterer, Bart Faatz, Jakob Andreasson, Marek Wieland, and Maria Krikunova, "THz streak camera performance for single-shot characterization of XUV pulses with complex temporal structures," Opt. Express 28, 20686-20703 (2020).
• E. Zapolnova, R. Pan, T. Golz, M. Sindik, M. Nikolic, M. Temme, M. Rabasovic, D. Grujic, Z. Chen, S. Toleikis and N. Stojanovic, "XUV-driven plasma switch for THz: new spatio-temporal overlap tool for XUV−THz pump−probe experiments at FELs",J. Synchrotron Rad. 27, 11-16 (2020).
• Kay Waltar, Johannes Haase, Rui Pan, Torsten Golz, Pavel Kliuiev, Michael Weinl, Matthias Schreck, Saša Bajt, Nikola Stojanovic, Jeroen A. van Bokhove, Matthias Hengsberger, Jürg Osterwalder, and Luca Castiglioni, "Polarization-sensitive reconstruction of transient local THz fields at dielectric interfaces", Optica 6 1431-1436 (2019).
• R. Pan, E. Zapolnova, T. Golz, A.J. Krmpot, M.D. Rabasovic, J. Petrovic, V. Asgekar, B. Faatz, F. Tavella, A. Perucchi, S. Kovalev, B. Green, G. Geloni, T. Tanikawa, M. Yurkov, E. Schneidmiller, M. Gensch and N. Stojanovic, "Photon diagnostics at the FLASH THz beamline", J. Synchrotron Rad. 26, 700-707 (2019).
• Zapolnova, Ekaterina, Torsten Golz, Rui Pan, Karsten Klose, Siegfried Schreiber, and Nikola Stojanovic. "THz pulse doubler at FLASH: double pulses for pump–probe experiments at X-ray FELs." Journal of synchrotron radiation 25, no. 1 (2018).
• Kovalev, S., Zhe Wang, J. C. Deinert, N. Awari, M. Chen, B. Green, S. Germanskiy et al. "Selective THz control of magnetic order: new opportunities from superradiant undulator sources." Journal of Physics D: Applied Physics 51, no. 11 (2018): 114007.
• Tavella, F., Höppner, H., Tkachenko, V., Medvedev, N., Capotondi, F., Golz, T., Kai, Y., Manfredda, M., Pedersoli, E., Prandolini, M.J. and Stojanovic, N., 2017. Soft x-ray induced femtosecond solid-to-solid phase transition. High Energy Density Physics.
• Finetti, Paola, et al. "Pulse duration of seeded free-electron lasers." Physical Review X 7.2 (2017).
• Kovalev, S., Green, B., Golz, T., Maehrlein, S., Stojanovic, N., Fisher, A.S., Kampfrath, T. and Gensch, M., 2017. Probing ultra-fast processes with high dynamic range at 4th-generation light sources: Arrival time and intensity binning at unprecedented repetition rates. Structural Dynamics, 4(2), p.024301.
• T. Oelze, B. Schütte, M. Müller, J.P. Müller, M. Wieland, U. Frühling, M. Drescher, A. Al-Shemmary, T. Golz, N. Stojanovic, and M. Krikunova, Correlated electronic decay in expanding clusters triggered by intense XUV pulses from a Free-Electron-Laser. Scientific Reports, 7 (2017)
  
• Liu, Y. F., K. Schnorr, G. Schmid, S. Augustin, S. Meister, H. Lindenblatt, A. Rudenko et al. "THz Streaking of the Autoionization Dynamics of O2 at the Free-Electron-Laser FLASH." In Journal of Physics: Conference Series, vol. 875, no. 4, p. 032031. IOP Publishing, 2017.
• B. Faatz et al., Simultaneous operation of two soft x-ray free-electron lasers driven by one linear accelerator, New Journal of Physics 18.6 (2016): 062002.
  
• B. Green et al., High-Field High-Repetition-Rate Sources for the Coherent THz Control of Matter, Scientific reports 6 (2016).
  
• S. Düsterer et al., Development of experimental techniques for the characterization of ultrashort photon pulses of extreme ultraviolet free-electron lasers, Physical Review Special Topics-Accelerators and Beams 17.12 (2014): 120702.
  
• V. Asgekar, G. Geloni, V. Kocharyan, N. Stojanovic, P. Michel, and M. Gensch, Interference effects in super-radiant THz sources, Infrared physics & technology 64 (2014): 26-32.
  
• N. Stojanovic, M. Drescher, Accelerator-and laser-based sources of high-field terahertz pulses, Journal of Physics B: Atomic, Molecular and Optical Physics 46(19), 192001 (2013).
  
• R. Riedel et. al., Single-shot pulse duration monitor for extreme ultraviolet and X-ray free-electron lasers, Nature Comm. 4 (2013), 1731.
  
• Gensch, M. "Super-radiant linac-based THz sources in 2013." Proceedings of FEL13, New York, 24-28.8. 2013, WEIBN0001 (2013).
• Schneidmiller, E. A., M. V. Yurkov, M. Krasilnikov, and F. Stephan. "Tunable IR/THz source for pump probe experiments at the European XFEL." In Advances in X-ray Free-Electron Lasers II: Instrumentation, vol. 8778, p. 877811. International Society for Optics and Photonics, 2013.
• B. Schütte et. al., Evidence for Chirped Auger-Electron Emission, Phys. Rev. Lett. 108 (2012) 253003.
  
• Först, Michael, Matthias C. Hoffmann, A. Dienst, Stefan Kaiser, M. Rini, R. I. Tobey, M. Gensch, C. Manzoni, and Andrea Cavalleri. "THz control in correlated electron solids: Sources and applications." In Terahertz Spectroscopy and Imaging, pp. 611-631. Springer, Berlin, Heidelberg, 2012.
• C. Kaya et. al., Phase sensitive monitoring of electron bunch form and arrival time in superconducting linear accelerators, App. Phys. Lett. 100 (2012), 1441103.
  
• M. Först, M. Gensch, R. Riedel, F. Tavella, E.A. Schneidmiller, N. Stojanovic, M.V. Yurkov, Optical Afterburner for a SASE FEL: First Results from FLASH, THPC84, IPAC2011, San Sebastián, Spain, (2011).
  
• F. Tavella, N. Stojanovic, G. Geloni, M. Gensch, Few Femtosecond Timing at Fourth Generation X-ray Light sources, Nat. Photon. 5 (2011), 162.
  
• Gensch, M. "THz pulses from 4th generation X‐ray lightsources: Perspectives for fully synchronized THz pump X‐ray probe experiments." In AIP Conference Proceedings, vol. 1214, no. 1, pp. 19-22. AIP, 2010.
• O. Grimm et al., Magnetic measurements with the FLASH infrared undulator, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 615.1 (2010): 105-113.
  
• U. Fruehling, et. al., THz-field driven X-ray streak camera, Nat. Photon. 3 (2009), 523.
  
• K. Tiedtke et al., The soft x-ray free-electron laser FLASH at DESY: beamlines, diagnostics and end-stations New journal of physics 11.2 (2009): 023029.
  
• M. Gensch et. al., New infrared undulator beamline at FLASH, Infrared Phys. Technol. 51, 423-425, (2008).
  
• B. Faatz et al., Development of a pump-probe facility combining a far-infrared source with laser-like characteristics and a VUV free electron laser, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 475.1 (2001): 363-367.
  
• M. Wieland et al., Deriving x-ray pulse duration from center-of-energy shifts in THz-streaked ionized electron spectra, Optics Express Vol. 29, No. 21 /11 (2021).