High-Field High-Repetition-Rate Terahertz facility @ ELBE (TELBE)
Available TELBE terahertz pulse energies as a function of terahertz frequency (left), and representative electric field transients for the undulator source (after 0.3 THz bandpass filter) and the coherent diffraction radiator (CDR) (right).
Foto: Jan-Christoph Deinert
As part of an upgrade of the ELBE accelerator one electron beamline has been modified to allow for the generation and acceleration of ultra short (< 150 fs) highly charged (up to 1 nC) electron bunches. This upgrade enables the operation of High-Field THz sources based on superradiant THz emission at the ELBE accelerator and thereby opens up the opportunity to generate carrier-envelope phase stable high-field THz pulses with extremely flexible paramaters with respect to repetition rate, pulse form and polarization. Since 2014 the fs electron beamline and the pilot-TELBE facility have been taken into operation [1,2] and have been comissioned aiming to achieve the following design parameters:
Radiator type | Electron charge / pC | Repetition rate / kHz | Pulse energy / μJ | Bandwidth / % | number of Field cyles | Timing / fs | Frequency range / THz |
Undulator | < 100 | =< 1.3 x 104 | 1 | ~20 | 8 | < 30 (FWHM) | 0.1 - 3 (tunable by user) |
< 1000 | =< 500 | 100 | ~20 | 8 | < 30 (FWHM) | 0.1 - 3 (tunable by user) | |
Diffraction radiator |
< 100 | =< 1.3 x 104 | 0.25 | 100 | 1 | < 30 (FWHM) | 0.1 - 3 |
< 1000 | =< 500 | 25 | 100 | 1 | < 30 (FWHM) | 0.1 - 3 |
TELBE is open since 2016 as user facility, proposals can be submitted via the central user portal. The available in-lab laser infrastructure allows THz-pump laser-probe experiments within a wide range of experimental schemes and probe beam properties. Please note that the TELBE sources are under constant development, current achievable parameters are (as of February 2021):
Radiator type | Electron charge / pC | Repetition rate / kHz | Pulse energy / μJ | Bandwidth / % | Number of field cycles | Timing / fs | Frequency range / THz |
Undulator | up to 250 |
25 to 500 |
<= 10 | 20 | 8 | < 30 | 0.1 - 1.5 |
Diffraction Radiator | up to 250 |
25 to 500 |
<=0.25 | 100 | 1 | < 30 | 0.1 - 1.1 |
For further details and discussions of potential projects and experimental ideas please contact the TELBE team leaders (see below). The strong in-house expertise on ultrafast spectroscopic methods and the broad scientific background of the TELBE team allows strong on-site support during experimental planning, set-up and execution.
Pulses from both radiator types are transported into a dedicated, climatized laser laboratory which is equipped with the following infrastructure:
- fs laser-amplifier system 1: Coherent, Inc. RegA 9000
- fs laser-amplifier system 2: Coherent, Inc. RegA 9040
- fs laser-amplifier system 3: Coherent, Inc. Legend Elite
- fs laser amplifier system 4: Coherent Inc. Astrella HE
- FTIR spectrometer: BRUKER 80V
- 10 T split-coil magnet with optical access: OXFORD INSTRUMENTS SPECIAL SM4000-10
- Optical cryostats (liquid He cooling, vacuum and contact gas environment, 3.4 K to 500 K)
- High-Field THz pump probe set-ups based on optical rectification, photoconductive emitters,...
- ONLINE Pulse-to-pulse THz diagnostic endstation (fs arrivaltime, THz - spectrum & pulse energy,...)
- TR - Faraday rotation endstation
- TR - THz emission endstation [4]
- TR - Scattering-type nearfield microscopy [5]
- Extensive THz manipulation and diagnostics equipment
A novel prototype data aquisition scheme [2] has been developed that allows to determine the arrivaltime jitter and intensity instability of each individual TELBE THz pulse, enabling online and post mortem correction of the acquired data.
Contact:
Dr. Sergey Kovalev (TELBE team leader, beamline scientist)
Dr. Jan-Christoph Deinert (TELBE deputy team leader, Young Investigator Group "THz-driven dynamics at surfaces")
[1] B. Green et. al., "High-field High-repetition-rate Sources for the Coherent THz Control of Matter", Scientific Reports 6 22256 (2016). (nature.com)
[2] S. Kovalev et al., "Probing ultra-fast processes with high dynamic range at 4th-generation light sources: Arrival time and intensity binning at unprecedented repetition rates", Struct. Dyn. 4 024301 (2017). (scitation.org)
[3] S Kovalev et al., "Selective THz control of magnetic order: new opportunities from superradiant undulator sources", J. Phys. D: Appl. Phys. 51, 114007 (2018). (HZDR repository)
[4] Hafez, H.A., Kovalev, S., Deinert, JC. et al., "Extremely efficient terahertz high-harmonic generation in graphene by hot Dirac fermions" Nature 561, 507–511 (2018). (nature.com)
[5] F. Kuschewski et. al., "Optical nanoscopy of transient states of matter", Scientific Reports 5, 12582 (2015). (nature.com)