A5028550430- Terahertz technology and applications
- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Gyrotron and Vacuum Electronics Research
- Topological Materials and Phenomena
- Magnetic and transport properties of perovskites and related materials
- Photonic and Optical Devices
- Superconducting and THz Device Technology
- Particle Accelerators and Free-Electron Lasers
- Advanced Thermoelectric Materials and Devices
- Quantum and electron transport phenomena
- Metamaterials and Metasurfaces Applications
- Magnetic Properties and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Laser-Matter Interactions and Applications
- Heusler alloys: electronic and magnetic properties
- Quantum Mechanics and Non-Hermitian Physics
- Acoustic Wave Resonator Technologies
- Molecular Junctions and Nanostructures
- Magneto-Optical Properties and Applications
- Graphene research and applications
- Inorganic Fluorides and Related Compounds
- Multiferroics and related materials
- Near-Field Optical Microscopy
- Plasmonic and Surface Plasmon Research
Helmholtz-Zentrum Dresden-Rossendorf
2016-2023
Weatherford College
2022
Optica
2019
Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine
2019
University of Groningen
2016-2018
Trinity College Dublin
2016
Advanced Materials and BioEngineering Research
2016
Tata Institute of Fundamental Research
2011-2013
Indian Institute of Science Education and Research, Bhopal
2013
Abstract Ultrashort flashes of THz light with low photon energies a few meV, but strong electric or magnetic field transients have recently been employed to prepare various fascinating nonequilibrium states in matter. Here we present new class sources based on superradiant enhancement radiation from relativistic electron bunches compact accelerator that believe will revolutionize experiments this field. Our prototype source generates high-field pulses at unprecedented quasi-continuous-wave...
Abstract In high-energy physics, the Higgs field couples to gauge bosons and fermions gives mass their elementary excitations. Experimentally, such couplings can be inferred from decay product of boson, i.e., scalar (amplitude) excitation field. superconductors, Cooper pairs bear a close analogy Interaction between other degrees freedom provides dissipation channels for amplitude mode, which may reveal important information about microscopic pairing mechanism. To this end, we investigate...
Harmonic generation is a general characteristic of driven nonlinear systems, and serves as an efficient tool for investigating the fundamental principles that govern ultrafast dynamics. Here, we report on terahertz-field high-harmonic in three-dimensional Dirac semimetal Cd
Nonlinear optics is an increasingly important field for scientific and technological applications, owing to its relevance potential optical optoelectronic technologies. Currently, there active search suitable nonlinear material systems with efficient conversion a small footprint. Ideally, the system should allow chip integration room-temperature operation. Two-dimensional materials are highly interesting in this regard. Particularly promising graphene, which has demonstrated exceptionally...
We turn graphene from an inert electronic material to the most nonlinear for terahertz range using a small voltage.
Abstract Cuprate high- T c superconductors are known for their intertwined interactions and the coexistence of competing orders. Uncovering experimental signatures these is often first step in understanding complex relations. A typical spectroscopic signature interaction between a discrete mode continuum excitations Fano resonance/interference, characterized by asymmetric light-scattering amplitude as function electromagnetic driving frequency. In this study, we report new type resonance...
Narrow-band terahertz emission from coherently excited spin precession in metallic ferrimagnetic Mn3-xGa Heusler alloy nanofilms has been observed. The efficiency of the emission, per nanometer film thickness, is comparable or higher than that classical laser-driven sources based on optical rectification. center frequency films can be tuned precisely via composition range 0.20–0.35 THz, making this type a candidate for efficient on-chip emitters. Terahertz spectroscopy furthermore shown to...
Abstract Topologically protected surface states present rich physics and promising spintronic, optoelectronic, photonic applications that require a proper understanding of their ultrafast carrier dynamics. Here, we investigate these dynamics in topological insulators (TIs) the bismuth antimony chalcogenide family, where isolate response Dirac fermions at from bulk carriers by combining photoexcitation with below-bandgap terahertz (THz) photons TI samples varying Fermi level, including one...
Recent advancements of accelerator technology enable the generation carrier-envelope-phase stable THz pulses with high fields at adjustable repetition rates. The appropriate choice radiator allows narrow-band, spectrally dense, multicycle transients tunable frequency which are ideally suited to selectively excite low-energy excitations such as magnons or phonons. They also allow one study dependence nonresonant THz-field interactions various order parameters dynamic range. In this paper, we...
Non-linear materials are cornerstones of modern optics and electronics. Strong dependence on the intrinsic properties particular materials, however, inhibits at-will extension demanding non-linear effects, especially those second-order ones, to widely adopted centrosymmetric (for example, silicon) technologically important burgeoning spectral domains terahertz frequencies). Here we introduce a universal route efficient responses enabled by exciting Thomson scattering, fundamental process in...
We have explored the low-energy excitations in epitaxial thin films of Eu1-xSrxMnO3 [x = 0.50: spin-glass with short range charge-order and x 0.58: long charge-order] using terahertz time-domain spectroscopy. A finite frequency peak structure optical conductivity is observed at ∼3.5 meV for both films. While 0.58 film possesses distinct properties collective charge-density waves, same subtle shallower weaker 0.50 film. These data, corroborated by magnetization, provide unambiguous evidence...
In this study, a conceptually different approach for investigating magnetic phase transitions in ultra-thin films is presented. THz emission from laser-excited material used to monitor the magnetization dynamics during laser-driven antiferromagnetic ferromagnetic transition FeRh. The emitted signal calibrated against static magnetometry data measurements, giving direct measure of absolute moment sample on sub-picosecond timescale. technique is, therefore, highly complementary conventional...
We report on measurements of magnetic field and temperature dependence antiferromagnetic resonances in the prototypical antiferromagnet NiO. The frequencies vicinity 1 THz have been determined time-domain via time-resolved Faraday after selective excitation by narrow-band superradiant terahertz (THz) pulses at temperatures down to 3 K fields up 10 T. reveal two resonance modes, which can be distinguished their characteristic dependencies. nature modes is discussed comparison an...
The behavior of charge-density wave (CDW) condensates with the systematic introduction ferromagnetic (FM) and spin-glass phases in charge-ordered (CO) lattice Nd(0.5)Sr(0.5)MnO(3) (NSMO) Eu(0.5)Sr(0.5)MnO(3) (ESMO) epitaxial thin films was investigated by terahertz time-domain spectroscopy. optical conductivity (100)-oriented NSMO film, which CO has an insignificant volume FM phase, exhibits a peak attributes CDW collective excitation at ~3.2 meV. This becomes completely submerged Drude...
A conceptually new approach to synchronizing accelerator-based light sources and external laser systems is presented. The concept based on utilizing a sufficiently intense single-cycle terahertz pulse slice thereby intrinsically synchronized femtosecond-level part of longer picosecond in an electro-optic crystal. precise synchronization the order 10 fs demonstrated, allowing for real-time lock-in amplifier signal demodulation. We demonstrate successful operation with three benchmark...
Abstract In this research, electromagnetic waves absorbing multilayer composite structures have been developed for terahertz (THz) region. the recent past, most of efforts to absorb THz radiations are based on metamaterials or coatings, which narrowband and fragile in nature, respectively. Under work, we designed absorption. Magnetic materials structure shows more than 99% absorption 0.5–2 frequency region both TE TM polarizations. Mechanically stable with such broadband absorptivity huge...
Multi-color pump-probe techniques utilizing modern accelerator-based 4th generation light sources such as X-ray free electron lasers or superradiant THz facilities have become important science drivers over the past 10 years. In this type of experiments precise knowledge properties involved pulses crucially determines achievable sensitivity and temporal resolution. work we demonstrate discuss powerful role pulse- field-resolved- detection can play for improving precision pump - femtosecond...
In this Letter, the proof of principle for a scheme providing intrinsic femtosecond-level synchronization between an external laser system and fourth generation light sources is presented. The applicable at any accelerator-based source that based on coherent radiation from ultrashort electron bunches such as superradiant terahertz (THz) facilities or X-FELs. It makes use THz pulse generated by accelerator intrinsically synchronized gate signal electro-optical slicing. We demonstrate enables...
A new class of accelerator based terahertz user facilities is presented in this paper. The prototype facility operates two superradiant THz sources parallel providing simultaneously single cycle and multicycle pulses with an unprecedented combination high field repetition rate. generation on enhancement radiation generated by relativistic electron bunches from a compact SRF technology-based MeV level accelerator. currently achieved peak performance yields 2 uJ pulse energy at 100 kHz...
Despite decades of search for the pairing boson in cuprate high-Tc superconductors, its identity still remains debated to date. For this reason, spectroscopic signatures electron-boson interactions cuprates have always been a center attention. example, kinks quasiparticle dispersion observed by angle-resolved photoemission spectroscopy (ARPES) studies motivated decade-long investigation electron-phonon as well electron-paramagnon cuprates. On other hand, overlap between charge-order...
Complex frustrated magnetic structures in multiferroic hexaferrites are well tunable by temperature, field and doping. We investigated the influence of strong THz pulses generated superradiant sources on structure related electromagnons’ absorption Y- Z-type hexaferrites. While hexaferrite (Ba0.2Sr0.8)3Co2Fe24O41 polycrystal, observed changes transmission spectra were fully described sample heating, a blue-shift electromagnon frequency Y-type Ba0.2Sr1.8Co2(Fe0.96Al0.04)12O22 single-crystal...