ZnTe crystals for high-field THz driven phenomena research at TELBE - [e-mail]

Featured research:
The High-field THz-driven Phenomena group is performing different ultra-fast spectroscopic techniques with few femtosecond time resolution to investigate dynamics in matter driven by high-field THz pulses. The specific interest is to understand how matter can be controlled and/or manipulated in the electronic ground state by the transient electric and magnetic fields of intense (THz) photon pulses. For that purpose, the group operates several state-of-the-art laser-driven high-field THz sources and performes research on accelerator-based high-field THz and fs - X-ray source world-wide. The group is furthermore responsible for the development of the scientific programm of, the operation of as well as the user support and the inhouse-research at the currently commissioned High-field High-Repetition-Rate THz user facility TELBE.

TELBE already since 2014 serves as the Accelerator Research and Development (ARD) test facility for electron bunch diagnostic on quasi - cw low energy electron beams with in the "ARD subtopic III: fs-ps electron and photon beams" of the Helmholtz-research Association a topic of high relevance for the operation of quasi-cw linac driven large scale facilities such as LCLSII. Femtosecond level THz based electron bunch diagnostic is hence a second focus of the groups specific scientific interests.
Within the so called THz photondiagnostic collaboration (THODIAC), we collaborate intensively with colleagues at DESY (source development, electron bunch diagnostic, user experiments),CFEL, FUB, MBI and FHI (Pilot THz pump probe experiments), XFEL, HZB, DLR, TUD and the PTB (electron bunch diagnostics and THz photondiagnostic). Additionally the activities are supported by currently two BMBF projects: Spektrale Analyse und ortsaufgelöstes Monitoring von Elektronenpaketen durch THz-Strahlung (SAMoS) and Transient Nanoscopy in the deep Terahertz Range (TiNa) as well as two projects funded by the European Union: European Cluster of Advanced Laser Lightsources (EUCALL) and Terahertz RAdio communication using high ANistropy SPIn-torque REsonators (TRANSPIRE).The activities are furthermore are an essential part of the HZDRs participation in the HGF program topic Accelerator Research and Development (ARD).

Featured research:
Efficient metallic spintronic emitters of ultrabroadband terahertz radiation
Nature Photonics 10 (7) · October 2015
Terahertz electromagnetic radiation is extremely useful for numerous applications such as imaging and spectroscopy. Therefore, it is highly desirable to have an efficient table-top emitter covering the 1-to-30-THz window whilst being driven by a low-cost, low-power femtosecond laser oscillator. So far, all solid-state emitters solely exploit physics related to the electron charge and deliver emission spectra with substantial gaps. Here, we take advantage of the electron spin to realize a conceptually new terahertz source based on tailored fundamental spintronic/photonic phenomena in magnetic metal multilayers: a spin-dependent generalization of the photo-Dember effect, the inverse spin-Hall effect and a broadband Fabry-P\'erot resonance. Guided by an analytical model, such spintronic route offers unique possibilities for systematic optimization. We find that a 5.8-nm-thick W/CoFeB/Pt trilayer generates ultrashort THz pulses fully covering the 1-to-30-THz range.