Friday 6 September 2019

08:30-09:00 - Closing Session - Amphi Lavoisier

09:00-10:30 - Plenary Sessions - Amphi Lavoisier

Chairperson: Jérôme Tignon

09:00 Th-Pl-9

High-Resolution THz Spectroscopy With QCLs: From Lab To Space

Heinz-Wilhelm HÜBERS, German Aerospace Center, Berlin, Germany

09:45 Th-Pl-10

Fast And Sensitive Bolometric Terahertz Detection At Room Temperature Through Thermomechanical Transduction

Kazuhiko HIRAKAWA, Tokyo University, Japan

10:30-11:00 - Coffee Break

11:00-12:45 Parallel sessions Fr-AM

11:00-12:45 - Fr-AM-1 - Instrum. Astro 2 - Room 151

Chairperson: Paul F. Goldsmith

11:00 Fr-AM-1-1
Demonstration Of A Frequency-Agile Quantum Well Based THz Heterodyne Detector
Boris Karasik¹; Jonathan Kawamura¹; Changyun Yoo²; Mark Sherwin²; Mengchen Huang²; Ken West³; Loren Pfeiffer^3
1Jet Propulsion Laboratory, California Institute of Technology, United States; ²University of California at Santa Barbara, Physics Department, Inst. for Terahertz Science and Technology, United States; ³Princeton University, Dept. of Elec. Eng., United States

The field of THz mixers for astrophysics is dominated by superconducting hot-electron bolometers (HEBs), whereas Schottky-diode mixers have been the only devices suitable for planetary instruments. The Schottky mixers operate at ambient emperature, which is a great advantage for planetary applications, but are much less sensitive than the state-of-the art HEBs and require a 10^3 higher local oscillator (LO) power. Here, we have demonstrated a novel THz mixer which offers the best of both worlds: it operates at ~ 60 K (accessible by passive cooling on space), requires ~ ?W LO power, and has a potential to be as sensitive as the HEB mixer.

11:30 Fr-AM-1-2
Comprehensive Description Of Sideband Ratio Of 2SB SIS Receiver
Andrey Khudchenko¹; Ronald Hesper¹; F. Patricio Mena²; Andrey Baryshev^1
1University of Groningen / NOVA, Netherlands; ²Electrical Engineering Department, University of Chile, Chile

Sideband Ratio or so called Image Rejection Ration (IRR), is one of the key figures of merit of sideband separating (2SB) receivers. Although these kind of receivers are widely used in ground-based astronomy, a full description of their IRR pattern has not been performed yet. To solve this problem we have simulated the entire 2SB SIS receiver by combining models of RF and IF chains. It was found that the bottle neck of the IRR performance is not in the imbalance of individual RF and IF components, but in system imbalances determined by parasitic reflections in the RF and IF chains. Using that knowledge we have built a 2SB receiver based on SIS mixers for the APEX telescope in Chile, which has a state-of-the-art performance at frequencies 600-720 GHz.

11:45 Fr-AM-1-3
Wideband Sub-mm Wave Superconducting Integrated Filter-bank Spectrometer
Alejandro Pascual Laguna¹; Kenichi Karatsu¹; Andrea Neto²; Akira Endo²; Jochem Baselmans^1
1SRON, Netherlands; ²TUDelft, Netherlands

The design of an octave bandwidth sub-mm wave superconducting on-chip filter-bank spectrometer for Astronomy is presented. An array of THz band-pass filters subdivides the bandwidth 220-440 GHz into channels with a spectral resolution f/Δf of 400 and an average maximum coupling strength of 40%. The filter-bank performance is assessed by means of a transmission line formalism that approximates its behavior. The chip is under fabrication and its measurements will follow.

12:00 Fr-AM-1-4
Highly Sensitive And Compact THz Heterodyne Receiver Based On HEB And QCL At 2.7 THz
F Joint¹; G Gay²; PB Vigneron³; T Vacelet²; S Pirotta⁴; R Lefevre²; Y Jin⁴; L Lu⁵; AG Davies⁵; E Linfield⁵; Y Delorme⁶; Raffaele Colombelli^4
1C2N and LERMA, France; ²LERMA, France; ³C2N, France; ⁴Centre de Nanosciences et Nanotechnologies, France; ⁵University of Leeds, United Kingdom; ⁶LERMA, United Kingdom

We present the development of a highly sensitive and compact HEB/QCL heterodyne detection system. The HEB mixer is a NbN nano-bridge mounted in an integrated lens-antenna configuration. The local oscillator is a low power consumption and low beam divergence 3rd order distributed feedback quantum cascade laser with single mode emission at the target frequency of 2.7 THz. A new quasi-optical coupling scheme between the mixer and the local oscillator has been developed that allows the removal of the beam splitter and therefore a better transmission of the RF signal and a more compact detection system. The lowest uncorrected double side band receiver noise temperature of this system is about 880 K.

12:15 Fr-AM-1-5
Scanning Lens Phased Array For Submillimeter Wavelengths
Sjoerd Bosma¹; Maria Alonso-delPino²; Cecile Jung-Kubiak²; Darwin Blanco¹; Nuria Llombart^1
1Delft University of Technology, Netherlands; ²Jet Propulsion Laboratory, United States

In this contribution, we propose a hybrid electromechanical scanning antenna array architecture suitable for highly directive phased arrays at submillimeter wavelengths with field-of-views (FoV) of +/-30 degrees. The concept relies on combining electrical phase shifting of a sparse array with a mechanical translation of an array of lenses. The use of a sparse phased array significantly simplifies the RF front-end, while the translation of a lens array steers the element patterns to angles off-broadside, reducing the impact of grating lobes over a wide FoV. The mechanical movement of the lens array can be done using a low-weight, low-power piezo-actuators. In order to achieve wide bandwidth and steering angles, a novel leaky wave feed concept is also introduced. A 540 GHz prototype is currently under fabrication.

12:30 Fr-AM-1-6
Terahertz Schottky Mixers For Atmospheric And Planetary Sciences
Alain Maestrini¹; Lina Gatilova¹; Jeanne Treuttel¹; Yong Jin²; Antonella Cavanna²; Jérôme Valentin¹; Thibaut Vacelet¹; Alexandre Féret¹; Sylvain Caroopen¹; Grégory Gay¹; Sabrina Mignoni¹; Jean-Michel Krieg¹; Peter De Maagt³; Christophe Goldstein^4
1Observatoire de Paris, France; ²Centre of Nanoscience and Nanotechnology, France; ³ESA-ESTEC, Netherlands; ⁴Centre National d'Etudes Spatiales, France

Schottky Mixers are key components for building THz compact low-noise high-spectral resolution receivers dedicated to atmospheric and planetary sciences. This paper presents the state-of-the-art THz Schottky mixers developed by LERMA and C2N for space instruments and discuss receiver frontend architecture for future missions above 1THz.

11:00-12:45 - Fr-AM-2 - Defense and Security - Room 101

Chairperson: Bernard Fischer

11:00 Fr-AM-2-1
Terahertz Tag Identifiable Through Shielding Material
Ryoya Mitsuhashi; Toshinari Horiuchi; Kosuke Murate; Kodo Kawase
Nagoya University, Japan

In this study, a terahertz tag identifiable through a shielding material was developed. We propose a tag that employs a color-coded system, which is comprised of several plates of varying thickness placed two-dimensionally, wherein their thickness and location provide identification information. We also made a less expensive tag that uses polyethylene (PE) sprayed with a metal on both sides. Furthermore, we compared three machine-learning methods (support vector machine [SVM], K-nearest neighbor [KNN], and principal component analysis [PCA]-SVM) to improve the precision of identification.

11:30 Fr-AM-2-2
Terahertz Information Tag System With Over-100-bit/s Reading Speed
Tadao Nagatsuma; Yusuke Kujime; Masayuki Fujita; Tomoki Sagisaka; Li Yi
Osaka University, Japan

For secure and cost-effective information tags, terahertz tags based on photonic crystal slabs with a capacity of 108 bit/square centimeter are presented. Also, high-speed tag reader system using frequency and beam scanning techniques is successfully demonstrated at a bit rate of 131 bit/s in order to meet a need of practical applications.

11:45 Fr-AM-2-3
SAR Imaging Using Coprime Measurements At Millimeter Wave Band
Xu Zhu; Hiroki Mori
Toshiba Coporation, Research & Development Center, Japan

Some exiting imaging apparatuses for public security require a large number of measurements and thus put a stringent requirement on hardware design. In this paper, we propose a mmWave-based scanning method which applies SAR technology and coprime measurements, to reduce the number of measurements and the amount of data. The numerical results indicate that the proposed method significantly reduces the number of measurements and the amount of data to less than 16% of the standard SAR, thus it greatly reduces software and hardware costs.

12:00 Fr-AM-2-4
Security Screening System Based On Spectral Detection Of Gas Molecules By Tunable Terahertz-wave
Kouji Nawata; Yuma Takida; Yu Tokizane; Takashi Notake; Zhengli Han; Hiroaki Minamide
RIKEN Center for Advanced Photonics, Japan

We have developed a gate-type passenger screening system with throughput capability within one second for a passenger. A passenger attached methanol as a phantom chemical agent and passed in front of the gas sensing system. The system took in the atmosphere including naturally vaporized methanol and detected it as THz-wave absorption. The results indicate that THz-wave gas sensing system with high throughput capability provides a passenger screening technology without disrupting foot traffic.

12:15 Fr-AM-2-5
Fast Equivalent Monostatic Imaging Algorithm Of A Standoff MIMO Screening System At Terahertz Band
Hang Gao¹; Chao Li²; Shiyou Wu²; Guangyou Fang^2
1University of Chinese Academy of Sciences, China; ²Institute of Electronics, Chinese Academy of Sciences, China

Real-time imaging technology is receiving more and more attention in medical imaging, non-destructive testing, especially security screening. In this paper, a fast equivalent monostatic range migration algorithm (RMA) based on a standoff Multi-input multi-out (MIMO) Screening system is proposed at terahertz (THz) band. The collected multistatic data is calibrated approximately firstly to be transformed into the monostatic one. Then a high-efficiency RMA is adopted to realize the near real-time imaging. The performance and efficiency of the proposed algorithm are validated in the simulation, which demonstrate a potential of real-time imaging application in THz standoff MIMO screening systems.

12:30 Fr-AM-2-6
Enhanced THz Tags Authentication Using Multivariate Statistical Analysis
Salma Salhi¹; Florent Bonnefoy¹; Stephane Girard²; Maxime Bernier¹; Nicolas Barbot³; Romain Siragusa³; Etienne Perret³; Frederic Garet^1
1University of Savoie Mont Blanc, Laboratory IMEP-LAHC, France; ²University of Grenoble Alpes, Inria, LJK, France; ³University of Grenoble Alpes, LCIS, France

In this paper, we report on the unitary authentication of identically realized diffraction grating-based tags structures in the THz domain by using multivariate statistical analysis. We proceed to a dimension reduction with Principal Component Analysis (PCA) as a preprocessing step before a Gaussian classification and we evaluate the error rates. We then classify the tags using a Linear Discriminant Analysis (LDA). We demonstrate that PCA gives average error rates lower than 0.5% whereas LDA is able to classify the tags with error rates lower than 6.10-5 considering its 3 first axes.

11:00-12:45 - Fr-AM-3 - Radars - Room 269

Chairperson:

11:00 Fr-AM-3-1
Ultra-Compact Micromachined Beam-Steering Antenna Front-End For High-Resolution Sub-Terahertz Radar
Umer Shah; Adrian Gomez; Joachim Oberhammer
KTH Royal Institute of Technology, Sweden

KTH Royal Institute of Technology, KTH Royal Institute of Technology, Malvinas väg 10, plan 5, Sweden
This paper reports on an ultra-compact sub-THz frequency based beam-steering radar front end implementation utilizing a micromachined parallel plate waveguide based leaky wave antenna. In addition to achieving a high range resolution, we show a signal post-processing technique to achieve high angular resolution by splitting the measurement frequency range into smaller sections to isolate similar-range close-proximity targets into different frequency-scanning sections. This compact, 24x24x0.9 mm3, beam-steering front-end has a 28 dBi gain and achieves a range resolution of better than 1 cm for scanning over 220-300 GHz with a 45Ãfâ?sÃ,° field of view.

11:30 Fr-AM-3-2
Amplitude-modulated Continuous-wave Radar In The Terahertz Band Using A Resonant-tunneling-diode Oscillator
Adrian Dobroiu; Ryotaka Wakasugi; Yusuke Shirakawa; Safumi Suzuki; Masahiro Asada
Tokyo Tech, Japan

We present a terahertz-wave radar based on a resonant-tunneling diode (RTD) and capable to measure absolute distances with high precision. The RTD emits a continuous wave in the terahertz range and its output power can be easily modulated. By using two modulation frequencies and measuring the phase of the wave returning from the target, we achieved a precise distance measurement, with an error of 0.063 mm.

11:45 Fr-AM-3-3
A Novel Airborne Microwave Sounder Radiometer (HYMS)
Olivier Auriacombe
STFC, Harwell Campus, United Kingdom

An airborne heterodyne radiometer has been developed at the Rutherford Appleton Laboratory in order to observe oxygen spectral signatures around 60 GHz at an altitude above 40 km with high spectral resolution. It comprises low noise millimeter-wave amplifiers and a diplexer to split the channel into the lower side band (50.3 GHz - 57.3 GHz) and the upper side band (63.3 GHz - 67.9 GHz). A Schottky mixer in each band dowconverts the incoming signal into the Intermediate Frequencies (IF) and is then processed using a novel wideband fast Fourier transform digital spectrometer, which has an instantaneous bandwidth of 8 GHz and spectral resolution of 3 MHz. For this radiometer, we have measured a double sideband system noise temperature of 250 K and a noise equivalent differential temperature of 0.3 K with a spectral bandwidth of 10 MHz and an integration time of 300 ms.

12:00 Fr-AM-3-4
Engineering Qualification Model (EQM) Front-End Receivers For The Microwave Imager And Microwave Sounder Instruments Onboard MetOp-SG Satellites
Olivier Auriacombe
STFC, Harwell Campus, United Kingdom

Rutherford Appleton Laboratory Space Department (RAL Space) and Radiometer Physics GmbH are responsible for the provision of millimetre-wave front-end receivers operating from 165 GHz to 664 GHz for three instruments on board the MetOp Second Generation (MetOp-SG) satellites. Qualification of the Engineering Qualification Models (EQMs) is recently completed. This paper presents the results of the EQM qualification for receivers operating at 165 GHz, 183 GHz and 229 GHz for the MWS and MWI instruments.

12:15 Fr-AM-3-5
Signal To Noise Ratio Budget Of A Pico-Seconds Pulsed Radar System For Stand-Off Imaging
Arturo Fiorellini Bernardis; Paolo Sberna; Andrea Neto; Nuria Llombart
Delft University of Technology, Netherlands

Recently, powerful, reliable and cost-effective THz radiation photoconductive-emitters have been developed, providing up to 1mW of pulsed power in the range of frequencies between 0.1 and 0.7 THz. In this paper we study the potential use of such sources for future pulsed radar systems aiming at stand-off imaging applications. Specifically, we investigate the image frame rate and Signal to Noise Ratio budget that can be obtained using these photoconductive sources. It emerges that adopting a receiving array of 14 X 14? 200 elements, a 3D image with a Field of View (FoV) of 6cm X 6cm X 100cm and resolution of 4mm X 4mm X 1mm can be generated in 80Hz with a minimum SNR = 30dB, including realistic quasi-optical channel efficiencies.

12:30 Fr-AM-3-6
Accurate Terahertz Three-dimensional Subsurface Imaging By Range Points Migration Method
Takamaru Matsui; Shouhei Kidera
The University of Electro-Communications, Japan

This paper proposes the novel imaging algorithm based on the range points migration (RPM) for the terahertz (THz) subsurface three-dimensional imaging, which is suitable for general THz-time domain spectroscopic (THz-TDS) measurement. The effectiveness of the proposed method has been demonstrated by the THz-TDS measured data.

11:00-12:45 - Fr-AM-4 - THz Detectors 2 - Petit Amphi

Chairperson: Roger Lewis

11:00 Fr-AM-4-1
Carbon Nanotube Film Terahertz Detectors With Multiple PN Junctions
Ryogo Utaki; Kou Li; Meiling Sun; Yu Tokumoto; Yukio Kawano
Tokyo Institute of Technology, Japan

Carbon nanotube (CNT) films have been gradually focused on as the flexible absorbers of the terahertz (THz) imaging device to realize various kinds of THz applications regardless the shape/size of inspection objects. Despite its flexibility, the device structure optimization of the CNT film-based THz imagers has not been fully studied and further performance improvements are strongly required toward the social implementation. Here we developed the novel type CNT film THz detectors by integrating multiple PN junctions and successfully enhanced the THz response by a factor of 10 compared to conventional CNT film THz imagers.

11:30 Fr-AM-4-2
Terahertz Detectors Based On Plasmonic Excitations in Double CdTe/CdMgTe Quantum Wells
Dmitriy Yavorskiy¹; Maria Szola¹; Krzysztof Karpierz¹; Igor Wlasny¹; Rafal Bozek¹; Rafal Rudniewski²; Dawid Sniezek²; Piotr Nowicki²; Jerzy Wrobel²; Sergij Chusnutdinow²; Grzegorz Karczewski²; Tomasz Wojtowicz²; Jerzy Lusakowski^1
1University of Warsaw, Poland; ²Institut of Physics PAS, Poland

Double CdTe/CdMgTe quantum wells modulation doped with Iodine were etched to fabricate grids with a period of 8 µm and a geometrical aspect ratio (?) between 0.2 and 0.7. Etching removed only the well closer to the sample's surface. Transmission of terahertz radiation as a function of magnetic field (B) up to 10 T was measured at 2 K. The spectra show a single magnetoplasmon resonance (MPR) which position in B depends on ?. A huge amplitude of MPR, comparable to that of the cyclotron resonance, allows us to propose such structures as perfectly adapted for tuneable plasmonic terahertz detectors.

11:45 Fr-AM-4-3
The Optical Absorption Properties Of Metallic Gratings/GaAs-based Blocked Impurity Band (BIB) Hybrid Structure Detector
Yulu Chen¹; Wulin Tong¹; Xiong Yang²; Bingbing Wang¹; Chuansheng Zhang¹; Haoxing Zhang¹; Yongshan Hu¹; Liwei Hou¹; Xiaodong Wang^1
1The 50th Research Institute of China Electronics Technology Group Corporation, China; ²Shanghai Institute of Microsystem and Information Technology, China

A novel Terahertz (THz) detector based on metallic gratings/GaAs-based Blocked Impurity Band (BIB) hybrid structure was designed and simulated in this work. By setting the periodic metallic gratings as 100µm with 50µm width, the absorption peak of the hybrid structure detector exists at the wavelength of 249 µm, which is 4.84 times larger than the conventional BIB detector. Also, the resonate absorption peak can be modulated by changing the period of metallic gratings. Our design and simulation result provide a new scheme to fabricate the high-performance THz detector for the practical applications such as security check, biomedical treatment etc.

12:00 Fr-AM-4-4
THz Plasmon Resonance Absorption In CVD Graphene For Photodetection Applications
Elena Titova; Andrey Bylinkin; Vitaly Mikheev; Mikhail Kashchenko; Dmitry Svintsov
MIPT, Russian Federation

We demonstrate the experimental study of the gate-tunable surface plasmon resonance in a large area CVD graphene. The interesting result is that despite the small carrier mobility in graphene (~10^3 cm^2/V/s), the effect is clearly distinguishable above the Drude absorption background in the THz range (5-10 THz). We discovered that the proximity of the metal grating to graphene modifies the plasmon spectrum in the way that it depends on the metal stripes width, and not on the grating period. We formulated a simple theory that describes our experimental data.

12:15 Fr-AM-4-5
THz Detectors Based On Electromechanical Meta-atoms
Allegra Calabrese¹; Yanko Todorov¹; Djamal Gacemi¹; Mathieu Jeannin¹; Stéphan Suffit²; Angela Vasanelli¹; Carlo Sirtori^1
1Laboratoire de Physique de l'Ecole Normale Superieure, France; ²Laboratoire Matériaux et Phénomènes Quantiques, France

We will present a THz electromechanical meta-atom that can be used as a fast, room-temperature detector for THz waves. Contrary to the majority of infrared and THz electromechanical devices, our meta-atom is based on electric interactions instead of photothermal forces. We can thus overcome the finite response time imposed by heat diffusion and realize detectors with virtually no upper limit in the modulation bandwidth.

12:30 Fr-AM-4-6
Fabrication Of Electro-Optic Polymer Waveguide Devices For Continuous-Wave Terahertz Detection
Takahiro Kaji; Isao Morohashi; Yukihiro Tominari; Yoh Ogawa; Norihiko Sekine; Toshiki Yamada; Akira Otomo
National Institute of Information and Communications Technology (NICT), Japan

Organic electro-optic (EO) polymers have attracted attentions as materials for highly efficient and broadband terahertz wave generation and detection. In this study, we aim to develop continuous-wave (CW) terahertz detection devices and fabricated the devices consisting of EO polymer waveguides and gold antenna array.

11:00-12:45 - Fr-AM-5 - FEL 3 - Amphi Lavoisier

Chairperson: Vitaly Kubarev

11:00 Fr-AM-5-1
Real-time Terahertz Waveform Measurement By Using Relativistic Electron Streak Camera
In Hyung Baek¹; Hyun Woo Kim¹; Key Young Oang¹; Sunjeong Park¹; Hyeon Sang Bark¹; Junho Shin²; Jungwon Kim²; Kyu-Ha Jang¹; Kitae Lee¹; Young Uk Jeong^1
1Korea Atomic Energy Research Institute, Republic of Korea; ²Korea Advanced Institute of Science and Technology, Republic of Korea

In this talk, we introduce the novel technique for real-time measurement of a ultrafast optical field by utilizing the relativistic electron beam. The direct electron-field interaction of our real-time oscilloscope guarantees the signal integrity of THz waveform measurement with a sampling rate of 75 Ts/s.

11:15 Fr-AM-5-2
Upgrade Projects Of Mid-Infrared Free Electron Laser At Kyoto University For High Peak Power And Ultra-short Pulse Operation
Heishun Zen¹; Hideaki Ohgaki¹; Ryoichi Hajima^2
1Institute of Advanced Energy, Kyoto University, Japan; ²National Institutes for Quantum and Radiological Science and Technology, Japan

A mid-infrared Free Electron Laser (MIR-FEL) is a candidate to realize a high-repetition-rate attosecond hard X-ray source based on the high harmonic generation (HHG). A new project to conduct proof of principle experiment of HHG driven by a MIR-FEL has been started from November 2018. For this purpose, upgrade projects of MIR-FEL at Kyoto University (KU-FEL) has been started to achieve high peak power and ultra-short pulse operation.

11:30 Fr-AM-5-3
Electron Cyclotron Emission With Helical Wavefront In Millimeter Wave Regime
Yuki Goto¹; Shin Kubo²; Toru Tsujimura^2
1Nagoya University, Japan; ²National Institution for Fusion Science, Japan

Recently it has been shown that the radiation from a charged particle in spiral motion has a helical wavefront. Although the cyclotron emission exists universally in nature, the vortex property has not been featured because this property is normally canceled out due to the randomness in the gyro-phase of electrons. In order to generate the ECE with helical wavefront from multi-electron in cyclotron motion, we are developing a method to control the gyro-phase by the high power Right Handed Circularly Polarized (RHCP) wave. The electrons which have cyclotron motion around the magnetic field can be phase-matched by interaction with the external RHCP wave. The coherent radiation can be obtained from these phase matched electrons.

11:45 Fr-AM-5-4
THz-driven Bunch Compression And Timing Stabilization Of A Relativistic Electron Beam
Emma Snively; Mohamed Othman; Michael Kozina; Benjamin Ofori-Okai; Stephen Weathersby; Suji Park; Xiaozhe Shen; Xijie Wang; Matthias Hoffmann; Renkai Li; Emilio Nanni
SLAC National Accelerator Laboratory, United States

We demonstrate THz-driven bunch compression and timing stabilization of a relativistic electron beam in a shorted parallel plate structure. Coupling between the electron beam and orthogonally propagating quasi-single-cycle THz pulse produces an energy chirp and time-dependent change of the average energy which compresses the bunch length and compensates for the initial time-of-arrival jitter after a drift. Significant bunch compression down to < 40 fs rms and timing jitter reduction by up to a factor of 3 are measured 1 m downstream with a transverse deflecting structure driven by a parallel THz source.

12:00 Fr-AM-5-5
Pulse And Field-resolved Photon Diagnostics At A Superradiant THz User Facility
Min Chen¹; Michael Gensch²; Sergey Kovalev¹; Bertram Green¹; Jan Deinert¹; Zhe Wang¹; Igor Ilyakov¹; Nilesh Awari¹; Mohammed Bawatna¹; Semyon Germanskiy^1
1Helmholtz-Zentrum Dresden Rossendorf, Germany; ²Deutsches Zentrum für Luft und Raumfahrt (DLR), Terahertz und Laserspektroskopie, Germany

In this work we demonstrate an approach of double arrival time monitors (ATM), which is employed to increase synchronization level between external femtosecond laser systems and 4th generation light sources. With comparison to the single arrival time monitor technique, which is in routine operation supporting user's pulse resolved pump-probe experiments in superradiant THz facility (TELBE), we demonstrate more than twice increase in the temporal resolution from 50 fs to 20 fs (RMS) and elimination of temporal drifts, by applying the double ATM approach. The proposed technique opens a way for sub femtosecond synchronization within large-scale facilities and laser systems.

12:15 Fr-AM-5-6
Powerful Long-pulse THz-band Bragg FEL Based On Linear Induction Accelerator
Andrey Arzhannikov¹; Naum Ginzburg²; Andrey Malkin²; Nikolai Peskov²; Eugene Sandalov¹; Andrey Savilov²; Stanislav Sinitsky¹; Dmitry Skovorodin¹; Alexander Starostenko¹; Vladislav Zaslavsky^2
1Budker Institute of Nuclear Physics RAS, Russian Federation; ²Institute of Applied Physics RAS, Russian Federation

Project of high-power long-pulse THz FEL is initiated in collaboration between BINP and IAP RAS based on the linac 5 - 10 MeV / 2 kA / 200 ns of the new generation. The aim of this project is to achieve a record power level of ~ 100 MW and pulse energy content up to 10 J in the THz band. An advanced Bragg resonator capable to provide stable narrow-band generation in strongly oversized interaction space is one of the key components of this FEL. Proof-of-principle operation of FEM with the resonator of such type has been already demonstrated up to W-band and narrow band generation at multi-MW power level has been observed for the transverse oversize factor of ~ 5 wavelengths. The paper presents design parameters and results of simulations of novel THz-band FEL.

12:30 Fr-AM-5-7
Magnetic Field Measurement And Shimming Of Undulator For Terahertz Super-radiation Source
Longgang Yan; Derong Deng; Hao Zhang
Institute of Applied Electronics, China Academy of Engineer Physics, China

Magnetic field of undulator for super-radiation source was measured and shimmed using magnetic field measurement bench to satisfy requirements of specifications. In this paper, the method and results were introduced. Finally, the radiation characteristic was calculated and analyzed.

11:00-12:45 - Fr-AM-6 - Biomedical Imaging - Room 162

Chairperson: Gian-Piero Gallerano

11:00 Fr-AM-6-1
Infrared Nanoscopy Of Alive Biological Cells
Fritz Keilmann; Yasin Durmaz; Alexandra Goetz
Ludwig-Maximilians-Universität München, Germany

We report sealing alive cells in their native, wet environment by single-layer graphene, where graphene stabilizes the cell by tightly conforming with its surface and thus enables topographic AFM maps of the cell's surface. Furthermore, graphene's transparency to infrared near-fields enables local chemical recognition, at nominally 20-nm spatial resolution, by scattering scanning mid-infrared microscopy (s-SNOM) and spectroscopy (nano-FTIR). Here we demonstrate first infrared nanoscopy results of the surface of native E. coli cells that show rich spatial and spectral contrasts. Our achievement opens a new door into characterizing subcellular structures and components, of any alive cells. Infrared nanoscopy is certainly free of any need for labelling as in super-resolution fluorescence microscopy, and free of fixation and metallization procedures as in electron microscopy that kill and distort cells.

11:30 Fr-AM-6-2
Development Of A THz-TDS Scanner For Topographic Corneal Imaging
Arjun Virk; Zachery B. Harris; M. Hassan Arbab
State University of New York at Stony Brook, United States

Topographic imaging of corneal tissue would be a prominent indicator of many ocular diseases. Using the time of arrival of a reflected THz beam from the surface, we develop a setup where depth profiles can be extracted from a spherical target. Topographic information associated with the contour of corneal tissue can be extracted, such as radius, surface height and thickness variations. In this study we image several 3D printed spherical targets to determine the lateral and axial resolutions, and asymmetrical characteristics of our imaging system.

11:45 Fr-AM-6-3
Evaluation Of The Psychoemotional Human State Via Terahertz Image Of The Face
Ilya Ozheredov¹; Elena Berlovskaya¹; Olga Cherkasova²; Alexander Shkurinov¹; Dmitry Nikolaev³; Timofey Adamovich¹; Sergey Isaychev¹; Evgeniy Isaychev¹; Alexander Makurenkov¹; Alexander Varaksin⁴; Sergey Gatilov⁴; Nikolay Kurenkov⁴; Alexander Chernorizov^1
1Lomonosov Moscow State University, Russian Federation; ²Institute of Laser Physics, Russian Federation; ³Institute for Information Transmission Problems of the RAS (Kharkevich Institute), Russian Federation; ⁴CJSC Pattern Recognition Research Company, Russian Federation

An approach to evaluation of the psychoemotional human state is discussed. The approach is based on an analysis of simultaneously registering infrared (IR) and terahertz (THz) emissions of the human body. Simultaneous registration of IR - THz images of a human face and psycho physiological indicators is carried out in situations of physical stress (short-term intensive physical exercise - functional squat test), electrical stimulation and informational stress (cognitive load - simple arithmetic mental calculations). Using the special analysis of IR - THz images, subjects can be divided into classes according to the type of reaction under stressful conditions.

12:00 Fr-AM-6-4
Substrate-enhanced THz Nanoscopic Recognition Of Single Bacteria
Stephan Schäffer; Anna Katharina Wigger; Peter Haring Bolívar
University of Siegen, Germany

We report on 600GHz nano imaging of a single dried Pseudomonas fluorescens bacterium with a scattering-type THz nanoscope (THz-s-SNOM). The conserved bacterium, deposited and immobilized on a microscope slide, is resolved in the near field images. Contrast improvements of nearly one order of magnitude by appropriately choosing the supporting substrate are predicted from theoretical considerations.

12:15 Fr-AM-6-5
Relating Nanoparticle Geometry And Terahertz Reflectivity
Nicholas Lawler; Vincent Wallace; Tristan Clemons; Killugudi Swaminatha Iyer
University of Western Australia, Australia

We conducted terahertz thermometry using a terahertz time domain spectroscopy system (THz-TDS) with several different gold nanoparticle sizes and shapes, and surface plasmon resonance (SPR) induced by a 520nm laser. The change in terahertz reflectivity due to induction of SPR was related to nanoparticle geometry and is consistent with temperature changes measured by infrared imaging. This work allows for optimization of terahertz thermometry techniques via design of appropriate nanoparticles.

12:30 Fr-AM-6-6
Stretchable Terahertz Imagers For Wearable Bio-monitoring Applications
Yu Tokumoto¹; Kou Li¹; Teppei Araki²; Yoshiko Harada²; Tsuyoshi Sekitani²; Yukio Kawano^1
1Tokyo Institute of Technology, Japan; ²Osaka University, Japan

Imaging technology in the field of terahertz (THz) waves have great potential for powerful non-invasive methods. However, most real objects including human body have three-dimensional curvatures and existing THz technologies often encounter difficulties in imaging such configurations, which limits the useful range of THz imaging applications. The recent progress in the terahertz imaging device is a carbon nanotube (CNT)-based device that shows the high absorption ratio in the broadband frequency region under mechanical bending. In this report, the mechanical flexibility is enhanced for the THz imager which enables the THz wave detection under mechanical stretching. The developed techniques are highly possible to contribute to non-stressful and wearable applications for bio-monitoring.