Topical meeting 06
Terahertz Science and Applications
(TSA)

Chair

Daniel Mittleman Brown University, USA

Co-chairs

Koichiro Tanaka Kyoto University, Japan	Peter Uhd Jepsen Technical University of Denmark, Denmark	Yutong Li Institute of Physics, Chinese Academy of Sciences, China	Xiaojun Wu Beihang University, China

Program Committee Members

Juncheng Cao, Shanghai Institute of Microsystem and Information Technology, CAS, China

Tie Jun Cui, Southeast University, China

Franz X. Kaertner, Deutsches Elektronen Synchrotron, Germany

Junichiro Kono, Rice University, USA

Aaron Lindenberg, Stanford University, USA

Tsuneyuki Ozaki, Institut National de la Recherche Scientifique, Canada

Kaushik Sengupta, Princeton University, USA

Wei Shi, Xi'an University of Technology, China

Alexander Shkurinov, Lomonosov Moscow State University, Russia

Jun Takeda, Yokohama National University, Japan

Nanlin Wang, Peking University, China

Hyunsoo Yang, National University of Singapore, Singapore

Weili Zhang, Oklahoma State University, USA & Tianjin University, China

Yan Zhang, Capital Normal University, China

Yaxin Zhang, University of Electronic Science and Technology of China, China

Yiming Zhu, University of Shanghai for Science and Technology, China

Invited Speakers

	Anne-Laure Calendron, Deutsches Elektronen Synchrotron, Germany Title: Strong-field THz Source for Magneto-optic Experiment Abstract: We report on strong-field, ultrabroadband THz radiation generation for magneto-optic experiment, demonstrated with the resonant excitation and dynamically resolved relaxation measurement of FeBO3. Tunability of the central frequency of the THz pulses is demonstrated experimentally.
	Juncheng Cao, Shanghai Institute of Microsystem and Information Technology, CAS, China Title: Terahertz Semiconductor Quantum Devices and Their Applications Abstract: We have developed Terahertz (THz) semiconductor quantum cascade lasers (QCL) and THz quantum well photodetector (QWP). We demonstrate the real-time THz communication and imaging based on the THz QCL and THz QWP.
	Yanping Chen, Shanghai Jiao Tong University, China Title: Controllable Terahertz Radiation from Two-color Laser Filaments Abstract: We report effective controls of waveform (CEP), angular distribution and polarization of a THz pulse radiated from a two-color air-filament by manipulating the filament length and initial phase difference between the two-color laser components.
	Tie Jun Cui, Southeast University, China Title: Information Metasurface Systems Abstract: Digital coding representation of metasurface makes it possible to control electromagnetic waves in programmable way and in the mean time to process information in real time, thus developing metasurface imaging systems and wireless communication systems.
	Jozsef Andras Fulop, University of Pecs, Hungary Title: Microstructured Intense THz Sources Abstract: Novel compact LiNbO3 and semiconductor THz sources, based on the tilted-pulse-front technique, enable straightforward scaling to unprecedented focused field strengths up to 50 MV/cm in the low-frequency part of the THz spectrum.
	Hassan A. Hafez, Bielefeld University, Germany Title: Graphene: The Ultimate Nonlinear Material at Terahertz Frequencies Abstract: Graphene is an exceptional nonlinear material at terahertz (THz) frequencies, providing highly efficient THz high harmonics generation with nonlinear coefficients several orders of magnitude larger than those of other solids.
	Martina Havenith, Ruhr-University Bochum, Germany Title: Non-linear THz Spectroscopy in the Liquid - Resolving the Mysteries of Water" Abstract: I present results of non-linear THz experiments to probe solvation dynamics upon photo-excitation and protein solvation."
	Mona Jarrahi, University of California Los Angeles, USA Title: High-efficiency Wavelength Conversion through Plasmonic Photoconductive Nanostructures Abstract: We demonstrate high-efficiency wavelength conversion from terahertz to radio frequencies through plasmonic photomixing. Through this scheme, we achieve heterodyne terahertz detection with quantum-level sensitivity at room temperature, for the first time.
	Franz X. Kaertner, Deutsches Elektronen Synchrotron, Germany Title: Terahertz Acceleration and the Picture Abstract: We develop a Terahertz driven accelerator technology with the goal to construct compact electron and X-ray sources. Here, we use a two-stage segmented-terahertz-electron-accelerator-and-manipulator (STEAM) setup to demonstrate greatly improved electron beam energy and emittance.
	Pernille Klarskov, Aarhus University, Denmark Title: Sub-wavelength THz Imaging of Semiconductor Carrier Dynamics Abstract: Terahertz technology has proven itself as a powerful tool to study carriers in semiconductors. In this presentation, we discuss how to overcome the diffraction-limit to perform subwavelength imaging of structures on the micro- and nanoscale.
	Junichiro Kono, Rice University, USA Title: Terahertz Strong-Field Physics without a Strong Field Abstract: We have observed ultrastrong resonant light-matter and matter-matter coupling in condensed matter systems in the terahertz frequency range. The coupling strengths in these systems were enhanced through Dicke cooperativity.
	Guoqian Liao, Science & Technology Facilities Council, England Title: Terahertz Bursts from Relativistic Laser-plasma Interactions: Generation, Manipulation, and Preliminary Applications Abstract: The generation of terahertz (THz) radiation from relativistically intense laser-plasma interactions is studied systematically under various laser and plasma conditions. High-energy tunable THz pulses are demonstrated and the underlying generation physics is explored.
	Tsuneyuki Ozaki, Institut National de la Recherche Scientifique, Canada Title: Nonlinear Interaction of Intense THz Pulses with Matter - Semiconductors and DNA Abstract: Using intense quasi-subcycle THz sources, we demonstrate various highly nonlinear THz effects in semiconductors. We also describe experimental results that show the first clear evidence of THz-induced disassembly of DNA nanostructures in solution.
	Yan Peng, University of Shanghai for Science and Technology, China Title: Application of Terahertz Precision Spectrum in Biomedical Detection Abstract: Sigle-shot terahertz time-domain spectroscopy is developed experimentally to measure the conductivity of warm dense golden plasma with temporal resolution while the theoretical models are established to predict the structures and dynamics of warm dense matter.
	Hua Qin, Suzhou Institute of Nanotech and Nanobionics, CAS, China Title: Ultrafast Terahertz Response of Antenna-coupled AlGaN/GaN HEMT Abstract: In an antenna-coupled AlGaN/GaN high-electron-mobility transistor (HEMT), incident terahertz electromagnetic wave modulates simultaneously the electron velocity and density and hence induces an unidirectional current in the gated channel. Upon intense terahertz irradiation, both electron velocity and density modulations may become strongly nonlinear. In this talk, preliminary results on such nonlinearity will be discussed based on autocorrelation measurements with terahertz free-electron laser pulses.
	Stefan Schlauderer, University of Regensburg, Germany Title: Terahertz Subcycle Control of Charge, Spin & Pseudospin Abstract: Utilizing the carrier wave of terahertz pulses, we drive all-ballistic Dirac currents on topological insulators and control the valley pseudospin in monolayer WSe2. Antenna-enhanced single-cycle terahertz pulses ballistically switch the antiferromagnetic spin order in TmFeO3.
	Kaushik Sengupta, Princeton University, USA Title: Towards Universality in Chip-scale Terahertz Systems Abstract: Silicon-based Terahertz systems is a field that is only about a decade old. In this time, we have seen a phenomenal growth of silicon systems operating at THz frequencies for a wide range of applications in sensing, imaging and communication. It can be argued that both the ‘THz gap’ and the ‘technology and applications gap’ is closing in meaningful ways in the THz range. Technologies beyond 100 GHz focusing on sensing, imaging and wireless back-haul links are getting attractive as we enter into a new area of highly dense network of autonomous systems requiring ultra-high speed and reliable links.
	Mostafa Shalaby, Capital Normal University, China & Swiss Terahertz LLC, Switzerland Title: Ultrafast Magnetic Recording in GdFe with Terahertz Light Abstract: we report on the first demonstration of ultrafast magnetisation switching of a spin-ordered material using single-cycle, intense THz pulses at a central frequency of 2 THz "
	Zhigao Sheng, High Magnetic Field Laboratory, CAS, China Title: THz Magneto-optic System and its Application in 2D Materials Abstract:Terahertz (THz) generally refers to sub-millimeter electromagnetic waves with frequencies between 1011 and 1013 Hz. Benefit from its excellent spectral performance, terahertz-related technology possesses great application potential in fields of communication, sensing, national security, and especially fundamental research. Here, we will briefly introduce our self-built THz magneto-optic measurement system and its functions. Afterwards, studies of mechanical THz modulation effect and possible THz emission in 2D materials will be presented. For the first work, a device prototype based on single-layered graphene is constructed and systematically studied and presents excellent modulation effect. For the second work, a phonon related THz oscillation in a ferromagnetic 2D materials was discovered.
	Wei Shi, Xi'an University of Technology, China Title: Study on Carrier Avalanche Quenching and Terahertz Radiation of GaAs in Strong Electric Field Triggered by Weak Light Abstract: Terahertz time domain spectroscopy (THz-TDS) has broad application prospects in material properties, material testing, sample identification, environmental monitoring, non-destructive testing, food safety and other fields. GaAs photoconductive antenna has been widely used in THz-TDS system as a THz emitter, but its power has not yet met people's expectations. Higher power terahertz sources are needed to enable THz-TDS system to measure water-bearing samples such as cells and nerves in vivo, to achieve ps time-resolved transient testing and to detect samples in the order of femoral magnitude. In this paper, the research progress of the nonlinear photoconductive terahertz radiation source is reported. Through theoretical analysis and experimental research, we found that GaAs photoconductive antenna could work with carrier avalanche multiplication mode when it was triggered by femtosecond laser with nJ order energy; the duration of carrier avalanche multiplication can be shortened by using the quenching mode of photo-excited charge domain; and a GaAs photoconductive antenna with the nonlinear effect of carrier avalanche quenching can be used to generate strong terahertz electromagnetic radiation.
	Alexander Shkurinov, Lomonosov Moscow State University, Russia Title: Terahertz Non-linear Phenomena in Liquid Gas Abstract: I present the results of research, on the generation of terahertz (THz) radiation under the action of femtosecond laser pulses on liquid nitrogen (LN). Our experimental results supported by theoretical interpretation, showed that under femtosecond laser radiation, liquid and gas emit THz waves in a very different way.
	Jun Takeda, Yokohama National University, Japan Title: Ultrafast Electron Manipulation Using THz Scanning Tunneling Microscopy with Tailor-made Near Fields Abstract: We successfully demonstrate the ultrafast phase-resolved and sub-cycle electron manipulation using terahertz (THz) scanning tunneling microscopy with tailor-made near fields tuned by a THz phase shifter.
	Kejia Wang, Huazhong University of Science and Technology, China Title: THz Computed Tomography and its Application on the Cultural Relices Abstract: We employ the THz computed tomography to solve a problem, i.e. how to display the hidden contents in a scrolled painting and calligraphy without truly opening them
	Nanlin Wang, Peking University, China Title: Photo-induced Nonequilibrium Response in Cuprate Superconductors Probed by Time-resolved Terahertz Spectroscopy Abstract: We present our recent work on the construction of an ulstrafast broadband infrared (ranging from 1.2 mm - 15 mm and beyond) pump - THz probe system in a reflection geometry and its application to the c-axis charge dynamics of cuprate superconductors La2-xBaxCuO4 (LBCO) and YBa2Cu3O6.45 (YBCO).
	Yang Wu, National University of Singapore, Singapore Title: THz Spintronics: From THz Generation to Novel Material Characterization Abstract: The talk will start from the introduction of new spintronics THz emitter, and then discussing about material characterization through the THz emission from novel materials, eventually, extending to functioning devices and systems.
	Xinlong Xu, Northwest University, China Title: Terahertz Technology for Two-dimensional Materials Abstract: THz spectroscopic technology has been used to characterize two-dimensional layered materials. The impedance matching property, THz emission mechanism, and ultrafast carrier dynamics of the two-dimensional materials in THz region are also discussed.
	Lixin Yan, Tsinghua University, China Title: Generation of Chirped THz Radiation with Ultrashort Electron Bunches Abstract: In this presentation, we will report on high power coherent THz development via different mechnism based on Linac beam line at Tsinghua University. A new beam line for novel tunable THz generation study is under design and will be bulit soon.
	Chao Zhang, University of Wollongong,  Australia Title: Transverse Electric Surface Plasmon Polaritons in a Dielectric-Graphene-Dielectric Structure in Sub-terahertz Regime " Abstract: We demonstrate a new low-frequency transverse electric SPP in the terahertz (THz)/subTHz regime in a dielectric-graphene-dielectric structure. The TE SPP is generated by the strong nonlinear response in graphene. Furthermore, unlike any other known SPPs located outside the radiation zone, a significant part of the low frequency TE SPP mode falls in the radiation zone. "
	Dongwen Zhang, National University of Defense Technology, China Title: Conductivity of Warm-dense Matter in Terahertz Range Abstract: Single-shot terahertz time-domain spectroscopy is developed experimentally to measure precisely the conductivity of warm dense golden plasma with temporal resolution while the ab-initial principle-based theoretical models and simulation approaches are established to predict exactly the structures and the dynamics of warm dense matter.
	Weili Zhang, Oklahoma State University, USA & Tianjin University, China Title: Dielectric Function of Terahertz Meta-devices Abstract: We study dielectric metasurfaces using the state-of-the-art terahertz time-domain spectroscopy and terahertz near-field spectroscopy in both fee space and near-field with an ultimate goal of developing high-efficiency next-generation integrated terahertz devices and components.
	Yan Zhang, Capital Normal University, China Title: Active Terahertz Wave Front Modulator Based on Metasurface Abstract: Active metasurface devices formed with photo-induced carriers in a silicon wafer are employed to dynamically modulate the wave-front of terahertz radiation. Proof of concept experiments are carried out to demonstrate the validity of this method.
	Yaxin Zhang, University of Electronic Science and Technology of China, China Title: High Speed THz Modulator within 2DEG Active Metasurface Abstract:In this presentation, we present different kinds of Spatial THz modulators based on the active 2DEG metasurface. The high speed modulator with various mechanisms such as resonant mode conversion, tunable collectivization- atomization state conversion and mode coupling have been shown. The amplitude modulator with up to 93% modulation depth and more than 3GHz modulation speed; the phase modulator with 137 degree phase shift in the THz transmission mode have been achieved.
	Zheng Zheng, Beihang University, China Title: 50 MHz-resolution Terahertz Time-domain Spectroscopy Based on a Simple Fiber Laser Abstract: Ultrahigh resolution terahertz time-domain spectroscopy (TDS) is realized by a low-complexity system featuring a dual-comb mode-locked fiber laser and adaptive sampling. It breaks the TDS's long-time performance bottleneck in spectral resolution with an affordable platform.
	Liguo Zhu, China Academy of Engineering Physics, China Title: Terahertz Wave Microscope with a Spatial Resolution of Over λ/100 Enabled by Near-field Compressive Sensing Abstract: In this talk, I’ll present a novel THz wave sub-diffraction-limited near-field microscopy. It is realized with reconfigurablely spatial modulating the near-field image and single-pixel detection in far field.