THz Opportunities for Industry: ABSTRACTS & PRESENTATIONS

 

Feb 11, 13:45-15:00

Director of Business Development, Zomega TeraHertz Corporation

Fundamentals of THz spectroscopy, applications, and technology

THz time-domain spectroscopy (or THz TDS) is the most widely used technique to characterize the spectral properties of materials in the THz band. In particular, most materials, especially organic ones, have their vibration and rotational modes in the THz band. Therefore, THz TDS is suitable technique to study such modes and obtain an understanding of molecular structure and dynamics. In this lecture, the principle of operation of a THz TDS, sample characteristics, and data analysis will be explained, including best practices for a proper measurement. The lecture will also review the most important applications and provide an overview of current technology. Applications have been developed for security and explosive and related compounds (ERCs). Technological development for these security applications has greatly improved the integration and user friendliness of THz spectrometers and current TDS spectrometers can be applied to other applications in the pharmaceutical and food safety industries.

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Feb 11, 15:30-16:45

TeraView's terahertz pulsed spectroscopy (TPS) measurements obtained in both transmission and reflectance modes advance the current state-of-the-art for elucidating solid state crystalline structures such as polymorphs, hydrates, and solvates by providing fundamental spectra-structure correlations for hydrogen-bonding and other organic moieties.

Terahertz pulsed imaging (TPI) provides a quick and non destructive 3D mapping technique for determining the composition and integrity of intact materials.  TPI yields unique information about materials.  These may arrange from NDE of

More recently, TeraView has been designing the next generation of time-domain reflectrometers (TDR) for use in semiconductor failure analysis as a non-destructive method for the location of defects in semiconductor device packages. An overview of terahertz technology and practical implementation considerations for TPS and TPI applications in industry will be discussed.  

 

Feb 11, 16:45-18:00

Department of Systems Innovation, Osaka University, Japan

Present and Future of Terahertz Communications

Recently, there has been an increasing interest in the application of terahertz waves to broadband wireless communications. In particular, the use of frequencies above 275 GHz is one of the strong concerns among radio scientists and engineers, because these frequency bands have not yet allocated at specific active services, and there is a possibility to employ extremely large bandwidths for ultra-broadband wireless communications. With steady increase in the operation frequency of semiconductor devices approaching the terahertz region, wireless communications using terahertz waves have become a real possibility. This lecture reviews recent progress in the research of terahertz communications using carrier frequencies from 100 GHz to 1 THz, including device development, envisioned applications, frequency allocation issues, future directions, etc.

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Feb 12, 9:00-10:10

Business Development Manager, Communications & Power Industries Canada, Inc. Georgetown, Ontario, Canada

Extended Interaction Klystrons for THz Applications

CPI Canada has produced EIKs and EIOs at frequencies from 9.6 GHz up to 264 GHz. The concepts of Klystron technology is described plus the modifications in the EIK that enable performance at medium power into the THz range. Recent studies indicate that the technology now exists to design and build Extended Interaction devices at frequencies up to 700 GHz. This paper describes current and predicted performance of EIK devices, the design challenges and solutions to enable performance specified by the requirements of various  applications.

 

 

Feb 12, 10:10-10:20

MENLO System GmbH, Martinsried, Germany

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Feb 12, 10:50-12:00

Senior Scientist, Centre de Recherche en Physique des Plasmas, EPFL, Lausanne, Switzerland

Gyrotrons from magnetic fusion to THz applications

Since more than three decades the research and development of gyrotrons has been driven from the need of high-power MW-level sources in the 100GHz range for electron cyclotron resonance heating of magnetically confined plasmas. A more recent spin-off research activity has led to the development of lower power (1-100W) gyrotrons with frequencies belonging to the THz domain. One of the main applications in the THz domain is in the field of DNP/NMR spectroscopy, but other applications such as ESR spectroscopy, plasma scattering diagnostics, X-ray detected magnetic resonance, etc. are also actively pursued.

Novel operational regimes have been recently experimentally demonstrated in which the non-linear interaction excites a finite number of side-bands and eventually ends in a chaotic dynamics of the THz radiation field. This novel regimes are consistent with numerical simulations and may open new applications for gyrotrons. 

These coherent sources are based on the cyclotron maser instability, the underlying physics and the basic concepts will be given in this course. A particular emphasis is placed on the design features for application for DNP/NMR spectroscopy were the continuous frequency tunability and/or a broad band radiation may be of interest.

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Feb 12, 13:45-15:00

Head of Solid State Probe Development, Bruker Biospin GmbH, Rheinstetten, Germany

NMR Signals Enhanced by Dynamic Nuclear Polarization. Application to Structural Biology and Material Science

 

     Nuclear Magnetic Resonance (NMR) is a very versatile method to study liquids and solids materials, e.g., the molecular, crystalline, or amorphous structure, and dynamics and has found widespread application, for example,  in analytical chemistry, physical chemistry, molecular biology, pharmacology, solid-state physics, and many other fields. Because of physical constraints (static magnetic fields available, low resonance frequencies in the radiofrequency range arising from the low gyromagnetic ratio of nuclear spins) NMR signals are inherently weak. Thus, much effort has been made to improve the strength of NMR signals. One technique to enhance NMR signals by one or two orders of magnitude relies on dynamic nuclear polarization, DNP, where the much higher polarization of  unpaired electron spins in the sample  is transferred to nuclear spins, e.g., to protons or 13C nuclei in the target molecules of interest. DNP requires the exposition of the electron spins by an electromagnetic field oscillating at electron spin resonance (ESR) frequencies that are in the range of approximately  10 to 500 GHz, depending on the applied constant magnetic field (0,3 to 19 Tesla).

   The talk introduces the basic concepts of magnetic resonance (NMR and ESR) and explains the fundamental processes of dynamic nuclear polarization. Several of these processes are briefly dicussed and their boundary constraints are highlighted as they determine the details of the DNP hardware necessary.  The instrumental requirements for DNP NMR are derived comprising the NMR hardware (magnet, rf system, NMR probe) and the DNP hardware (microwave source, waveguides, DNP hardware in the NMR probe).

   Finally, the motivation of all DNP developments consist in performing NMR experiments, which without DNP would either require excessive measurement times (weeks, months) or, as for the case of phenomena on solid surfaces, would not be possible at all. The examples discussed here are drawn from structural biology, particularly from structural proteomics, and from material sciences.

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Feb 12, 15:35-16:45

University College London, UK

Terahertz waveguide and waveguide characterization technologies

Technology of THz waveguides has seen a rapid progress in the last 10 years. Understanding of material absorption at THz frequencies, both on metallic surfaces and in dielectrics, has lead to demonstration of THz waveguides in which the major problem of very high transmission losses is mitigated. The level of transmission losses has been decreased from over 100 dB/m in early THz waveguides to below 1 dB/m in recent waveguides  [1].

Among several low-loss THz waveguide designs is the dielectric-lined hollow metallic waveguide [1]. The dominant mode profile in this waveguide allows realizing the general principle for achieving low transmission losses: the transmitted energy must be distributed in hollow regions. As a result, very low attenuation (1 dB/m) and relatively low dispersion (6 ps/THz/m) can be achieved in this waveguide. Another attractive characteristic of the dielectric-lined hollow cylindrical waveguides is the profile of the dominant HE11 mode. This mode can be coupled to free-space propagating beams very efficiently (~95%).

To minimize the impact of material absorption, low-loss THz waveguides are typically designed as multimode waveguides. The multimode designs however create a new challenge: precise characterisation of modal properties. Recently developed THz near-field microscopy methods in combination with the time-resolved capability of pulsed THz spectroscopy systems opened the possibility of waveguide characterization with modal analysis. The time-resolved near-field imaging allows distinguishing the waveguide normal modes and mapping their spatial profiles. This approach avoids the problem of mode interference occurring in the frequency domain characterisation techniques. Experimental studies allow evaluating the impact of the waveguide structure on the mode profile, whereas knowledge of the mode profiles provide intuitive understanding of waveguide losses and dispersion [3]. High spatial resolution of near-field probe also allows measurements of dispersion and losses for individual modes by positioning the probe in a location where the mode of interest has high amplitude whereas other modes have minimal amplitudes.

Recent THz waveguide research has been focused on fabrication of good quality waveguides, modeling, on waveguide characterization. Further development of the field will benefit from discoveries of more transparent dielectric materials for porous and photonic crystal waveguides and development of fabrication methods. Efficient coupling of THz waves from sources and detectors to THz waveguides is another challenging problem that must be solved to enable integration of THz waveguides with THz devices, such a quantum cascade lasers and photonic mixers. Recent developments and future challenges for THz waveguide technologies will be overviewed.

References

[1] O. Mitrofanov et al., IEEE Trans. on Terahertz Sci. and Technology, 1, 124, 2011.

[2] O. Mitrofanov et al., Appl. Phys. Lett., 94, 171104, 2009.

[3] O. Mitrofanov and J.A. Harrington, Optics Express, 18, 1898, 2010.

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Feb 12, 16:45-18:00

CTO – Virginia Diodes Inc.

Solid State Sources and Transceivers for High Dynamic Range THz Measurements

 

This talk will focus on the development of Schottky diode based solid-state THz sources and transceivers with state-of-the-art sensitivity. Schottky diodes have long been used to extend the capabilities of MMIC-based microwave technology into the THz. The use of microwave synthesizers combined with a heterodyne system architecture allows for measurement systems with 150 dB of dynamic range at 100 GHz and 100 dB at 750 GHz. This high dynamic range is a key enabling technology for a wide variety of applications ranging from molecular spectroscopy, active radar for imaging, communications, and general THz test and measurement. Topics that will be discussed during the talk include:

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Feb 13, 9:00-10:10

Institute of Electronics Microelectronics and Nanotechnology (IEMN), UMR CNRS 8520, Lille University, Villeneuve d’Ascq France

Optoelectronic terahertz generation

 

One solution for terahertz generation consists in using a non-linear phenomenon to down convert optical sources in the targeted range. A combination of a semiconductor photodetector and an antenna fabricated thanks to microelectronics techniques can be used for such frequency conversion. In this course we will describe the principle, the fabrication process, the characterisation and the performances of such systems. We will discuss the advantages and the limitations of this technique. We will describe also some applications in the spectroscopy, imagery and telecommunications domains.

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Feb 13, 10:10-10:25

LETI, CEA, Grenoble, France

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Feb 13, 10:50-12:00

Senior Research Scientist, Quantum Optoelectronics Group, Institute of Quantum Electronics, ETH Zurich

Terahertz quantum cascade lasers

 

In this talk we will review the current trends in the research on quantum cascade lasers (QCL) for emission in the THz portion of the electromagnetic spectrum. After reviewing the basics of quantum cascade lasers principles we will discuss high performance THz QCLs focussing of active region design and waveguide architecture. Then we will move to frequency control and tunability of the devices, discussing  distributed feedback lasers, photonic crystal cavities and microcavity lasers. Broadband operation and mode-locking of THz qcls will be also presented and  finally we will discuss some applications of these devices.

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