Sunday, 28 May 2017

Terahertz transmission vs reflection imaging and model-based characterization for excised breast carcinomas

Bowman, Tyler, Magda El-Shenawee, and Lucas K. Campbell. "Terahertz transmission vs reflection imaging and model-based characterization for excised breast carcinomas."  Biomedical Optics Express 7, no. 9 (2016): 3756-3783.
Abstract 
This work presents experimental and analytical comparison of terahertz transmission and reflection imaging modes for assessing breast carcinoma in excised paraffin-embedded human breast tissue. Modeling for both transmission and reflection imaging is developed. The refractive index and absorption coefficient of the tissue samples are obtained. The reflection measurements taken at the system’s fixed oblique angle of 30° are shown to be a hybridization of TE and TM modes. The models are validated with transmission spectroscopy at fixed points on fresh bovine muscle and fat tissues. Images based on the calculated absorption coefficient and index of refraction of bovine tissue are successfully compared with the terahertz magnitude and phase measured in the reflection mode. The validated techniques are extended to 20 and 30 μm slices of fixed human lobular carcinoma and infiltrating ductal carcinoma mounted on polystyrene microscope slides in order to investigate the terahertz differentiation of the carcinoma with non-cancerous tissue. Both transmission and reflection imaging show clear differentiation in carcinoma versus healthy tissue. However, when using the reflection mode, in the calculation of the thin tissue properties, the absorption is shown to be sensitive to small phase variations that arise due to deviations in slide and tissue thickness and non-ideal tissue adhesion. On the other hand, the results show that the transmission mode is much less sensitive to these phase variations. The results also demonstrate that reflection imaging provides higher resolution and more clear margins between cancerous and fibroglandular regions, cancerous and fatty regions, and fibroglandular and fatty tissue regions. In addition, more features consistent with high power pathology images are exhibited in the reflection mode images.


... work. 2. Methodology. 2.1 Pulsed terahertz system. The measurements in this work make use of the TPS 3000 pulsed terahertz imaging and spectroscopy system from TeraVIEW, Ltd. The system diagram can be seen in Fig. 1 ...

for full paper see https://www.osapublishing.org/boe/abstract.cfm?uri=boe-7-9-3756
for more information about TeraView see http://www.azom.com/equipment-details.aspx?EquipID=4411

Saturday, 27 May 2017

Frequency domain penetration loss in the terahertz band

Kokkoniemi, Joonas, Janne Lehtomäki, Vitaly Petrov, Dmitri Moltchanov, and Markku Juntti. "Frequency domain penetration loss in the terahertz band." In Millimeter Waves (GSMM) & ESA Workshop on Millimetre-Wave Technology and Applications, 2016 Global Symposium on, pp. 1-4. IEEE, 2016.

Abstract:
Results on penetration loss measurements in the THz frequencies between 0.1-2 THz are reported. The measurements were conducted with time domain spectroscopy using the TeraView TeraPulse 4000 measurement equipment. We concentrate on the frequency-dependent penetration characteristics of various materials typical for indoor environments, providing both qualitative and quantitative assessment. The results show that the lower end of the THz band (<; 0.5 THz) suffers only modest loss in comparison to the higher frequencies. For the materials considered in this paper, plastic, glass and hard-board, the exact penetration properties are both frequency- and material-dependent. The incident angle to the material increases the penetration loss through increased path length inside the material. The exact values of these losses are provided.

... The measurements were conducted with time domain spectroscopy using the TeraView TeraPulse 4000 measurement equipment. ... II. MEASUREMENT SETUP The measurements were made with the TeraView TeraPulse 4000 device. ...

for full paper see http://ieeexplore.ieee.org/abstract/document/7500309/

for more information about TeraView see http://www.azom.com/equipment-details.aspx?EquipID=4411

Friday, 26 May 2017

Terahertz Time-Domain Spectroscopy for In Situ Monitoring of Ceramic Nuclear Waste Forms

Clark, Braeden M., and S. K. Sundaram. "Terahertz Time-Domain Spectroscopy for In Situ Monitoring of Ceramic Nuclear Waste Forms." Journal of Infrared, Millimeter, and Terahertz Waves 37, no. 10 (2016): 993-1000.

Abstract
The use of terahertz time-domain spectroscopy (THz-TDS) is presented as a non-contact method for in situ monitoring of ceramic waste forms. Single-phase materials of zirconolite (CaZrTi2O7), pyrochlore (Nd2Ti2O7), and hollandite (BaCs0.3Cr2.3Ti5.7O16 and BaCs0.3CrFeAl0.3Ti5.7O16) were characterized. The refractive index and dielectric properties in THz frequencies demonstrate the ability to distinguish between these materials. Differences in processing methods show distinct changes in both the THz-TDS spectra and optical and dielectric properties of these ceramic phases. The temperature dependence of the refractive index and relative permittivity of pyrochlore and zirconolite materials in the range of 25–200 °C is found to follow an exponential increasing trend. This can also be used to monitor the temperature of the ceramic waste forms on storage over extended geological time scales.
... A Teraview TPS 3000 (Teraview, UK) was used to measure the spectra of the samplesfrom 0.1 to 1.2 THz at room temperature in transmission mode. A reference measurementwas made in pure nitrogen prior to the sample measurements. ...
for full paper see https://link.springer.com/article/10.1007/s10762-016-0289-2
for more information about TeraView see http://www.azom.com/equipment-details.aspx?EquipID=4411

Thursday, 25 May 2017

Call for papers Photonics West 2018


Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XI
This conference has an open call for papers:


Important
Dates

SHOW | HIDE
Abstract Due:
17 July 2017

Author Notification:
25 September 2017

Manuscript Due Date:
3 January 2018

Conference
Committee

SHOW | HIDE
Conference Chairs

Program Committee
  • René Beigang, Technische Univ. Kaiserslautern (Germany)
  • Jianji Dong, Huazhong Univ. of Science and Technology (China)
  • Frank Ellrich, Univ. of Applied Sciences Bingen (Germany)
  • Fabian Friederich, Fraunhofer-Institut für Physikalische Messtechnik (Germany)
  • Robert H. Giles, Univ. of Massachusetts Lowell (United States)
  • R. Jennifer Hwu, InnoSys, Inc. (United States)
Program Committee continued...
Call for
Papers
This conference brings together researchers and engineers from academia, industry, and government laboratories to explore and present work in the frequency range covering approximately less than 1 GHz (300 mm) to greater than 3 THz (100 μm). Papers on RF and millimeter technology including advances in wireless communications, radar, lidar, microwave and mm-wave photonics, metamaterials, antennas, phased array radar, modulation, security, monitoring, detection, imaging are encouraged. Papers in photonic-related fields including, but not limited to, radio over fiber (RoF) RF photonics including photonic generation of microwave signals, photonic processing of microwave signals, and photonic distribution of microwave signals and semiconductor (including Si, SiC, SOI, GaAs, GaN, InP, SiGe, diamond, graphene and other materials) RF, mm-wave and terahertz devices and related applications are also encouraged, as well as the hybrid photonic systems and applications. Terahertz (THz) technology deals with the generation and utilization of electromagnetic energy covering what is also known as the sub-millimeter wave region of the spectrum. In this region, which lies between the millimeter wave and far infrared spectral regions, materials exhibit properties that can be exploited to advantage for use over a broad range of important technologies and applications. Papers on terahertz photonics including photonic generation and detection of terahertz waves, THz lasers are also encouraged. 

This conference includes low- to high-power sources, detectors, systems, including both photonic and electronic modulated sources, detectors, and systems. At THz frequencies, the primary difficulty encountered by scientists and engineers working in this field is the lack of convenient and affordable sources and detectors of terahertz radiation, but this difficulty is gradually changing as new sources and improved detectors are being developed as the technology continues to mature and broaden. At RF and millimeter frequencies, more and more hybrid systems are being integrated with photonic devices that enhance the functions, specifications and stabilities tremendously compared to their traditional counterpart systems. The purpose of this conference is to gather scientists and engineers from a diverse set of disciplines, who are interested in either learning more about terahertz and sub-millimeter and millimeter wave and RF technology and related and coupled technologies, or who are contributing to the field through their own research, development, or manufacturing activities. 

Disciplines utilizing terahertz technology include physical chemistry (certain molecules or molecular segments exhibit strong resonances in the 10 cm-1 to 100 cm-1 spectral region), military, and homeland security (terahertz radiation can penetrate clothing and packing materials but is reflected by metals and other materials), biomedical technology (tissue exhibits reflection and absorption properties that change dramatically with tissue characteristics), medical and dental, secure short-distance wireless communications (atmospheric water content prevents terahertz radiation from traveling very far), astronomy (the cold background of the universe exhibits a peak in this spectral region), space communications (where the terahertz region is wide open for use) and other disciplines where new, yet-to-be-discovered applications will undoubtedly come forth. Since the low energy associated with terahertz radiation is expected to be no more harmful than infrared or microwave radiation, safety issues are not expected to limit the use of terahertz radiation at low-power levels. 

Papers on power supplies and electronic power conditioners and associated power protection systems including energy-efficient power supplies are also encouraged. 

Papers are solicited in the following and related areas: 

Terahertz sources

  • solid-state sources, electron-beam sources, vacuum electronics sources, frequency mixers, frequency multipliers, parametric oscillators, hybrids, graphene, FET and HEMT sources, gas lasers, quantum cascade lasers and related sources, p-germanium sources, photoconductive switches, resonant tunneling diodes, backward wave oscillators
  • novel stabilized photonic THz sources
  • fabrication processes
  • systems and systems integration.
RF, sub-millimeter-wave and millimeter-wave sources
  • power sources of all types in the range of 1 GHz to 300 GHz and 300 GHz and higher (i.e. from S-band to the higher end of the millimeter-wave frequencies and all of the sub-millimeter-wave frequency region)
  • novel stabilized photonic RF, millimeter-wave, sub-millimeter-wave sources.
Detectors
  • bolometers and other thermal detectors, Schottky and other mixers, thermopiles, quantum devices, antenna integrated detectors, heterodyne detection techniques, hybrid detection, direct detection techniques
  • transistor-based detectors including graphene, silicon, III-V, II-VI, nitride-based, etc.
  • theoretical modeling
  • novel detectors.
High-power sources, modules, and systems
  • THz, RF, millimeter-wave and sub-millimeter-wave high power sources
  • THz, RF, millimeter-wave and sub-millimeter-wave modules
  • THz, RF, millimeter-wave and sub-millimeter-wave systems
  • power supplies and support circuits, electronics, optoelectronics, systems.
Terahertz, RF, millimeter-wave, and sub-millimeter-wave passive components
  • optics, lenses, gratings, waveguides, photonic crystal structures and metamaterials, couplers, wire guides, other components.
Materials for THz and GHz devices
  • linear and nonlinear optical materials and devices
  • organic and inorganic source and modulator materials and devices
  • RF, millimeter-wave and sub-millimeter-wave materials, devices and fabrication processes
  • THz material systems
  • silicon (Si)-based
  • silicon carbide (SiC)-based
  • silicon-on-insulator (SOI)-based
  • gallium arsenide (GaAs)-based
  • gallium nitride (GaN)-based
  • indium phosphide (InP)-based
  • silicon germanium (SiGe)-based
  • quantum dot-(QD) based including for QDs for sensors, detectors and sources
  • diamond-based
  • graphene-based
  • other-based.
Enhancements, improvements and advances in RF, millimeter-wave and sub-millimeter wave generation, modulation and detection
  • RF, millimeter-wave and sub-millimeter-wave integrated photonic devices
  • RF, millimeter-wave and sub-millimeter-wave and photonic integration process development
  • RF, millimeter-wave and sub-millimeter-wave performance characterization
  • phased-array and single-element photonically-driven antennas
  • phased-array and single-element antennas, systems, concepts, approaches
  • low-Vp and wide-bandwidth modulators
  • direct-driven millimeter-wave lasers and amplifiers
  • millimeter-wave, sub-millimeter and THz photonic crystal devices and applications
  • RF, millimeter-wave, sub-millimeter-wave and THz photonic up- and down-converters
  • photonic phase locked loops
  • RF, millimeter-wave, sub-millimeter-wave, and THz MMICs
  • RF, millimeter-wave, sub-millimeter-wave, high power solid-state and electronic vacuum devices.
Simulations and modeling
  • simulations and/or modeling of RF devices, components, and/or systems
  • simulations and/or modeling of millimeter-wave devices, components, and/or systems
  • simulations and/or modeling of sub-millimeter-wave devices, components, and/or systems
  • simulations and/or modeling of THz devices, components, and/or systems
  • modeling of optical components, optical systems, imaging systems, wave propagation, modes, Gaussian beam characteristics, couplers, antennas, performance limitations, software designs.
Spectroscopy
  • terahertz and/or sub-millimeter spectroscopy, DNA segment identification, cell abnormalities, cancer identification and screening, imaging, medical and dental detection
  • identification of biological and chemical detection and fingerprinting
  • identification of hazardous, explosive, and/or dangerous materials
  • identification of chemical or biological threats
  • scalar and vector network analysis at sub-millimeter and terahertz frequencies
  • measurement techniques at sub-millimeter, millimeter, and terahertz frequencies
  • identification of organic and inorganic compounds using terahertz and/or sub-millimeter wave spectroscopy
  • high-speed and/or high-resolution spectroscopic techniques, methods, approaches
  • novel approaches, systems, designs, techniques, reflection, sensitivity, applications.
Biomedical applications
  • DNA identification, burn analysis, tissue abnormality identification, pharmaceutical, dentistry, medical, clinical, commercial applications
  • cancer, burn, and/or water content detection; high sensitivity, high contrast, etc.
  • biological and/or physiological aspects and/or related effects of RF, millimeter-wave, sub-millimeter-wave and/or THz
  • imaging techniques, methods, hardware design, strategies, technologies and techniques.
Communication and sensing systems
  • terahertz, RF, millimeter-wave and sub-millimeter-wave communications, media characteristics, wireless communications, inspection systems, detection systems, screening systems
  • RF, millimeter, sub-millimeter-wave and microwave links
  • RF, millimeter-wave, sub-millimeter-wave photonic communication and sensing systems
  • Internet of things (IOT) sensors, detectors and communication interfaces, protocols and implementations including but not limited to wireless sensors and wireless communications.
Imaging and security
  • RF imaging devices, components, and/or systems
  • millimeter-wave imaging devices, components, and/or systems
  • sub-millimeter-wave imaging devices, components, and/or systems
  • THz imaging devices, components, and/or systems
  • RF, millimeter-wave and sub-millimeter-wave active and passive imaging systems
  • x-ray imaging including components, systems, power supplies, applications, techniques, etc.
Astronomy and space and other areas of photonics, light, and matter
  • imaging techniques, ultra-sensitive detection, applications, programs
  • satellite communications
  • space based electronics and devices
  • satellite components and systems
  • space and satellite qualifications and testing
  • radiation hard electronics
  • high-energy physics and related topics
  • fusion and related topics
  • fission and related topics.
Innovations
  • new or novel terahertz, RF, millimeter-wave and sub-millimeter, microwave concepts, systems, applications
  • new or novel developments in THz or sub-millimeter waves including teaching, instruction, course offerings, simulations, conceptional and/or experimental procedures, implementations, concepts, etc.
Power supplies and electronic power conditioners
  • high-power power supplies
  • low- and ultra-low-power power supplies
  • low-noise power supplies
  • high- and ultra-efficient power supplies
  • associated power protection systems
  • energy-efficient power supplies
  • novel designs and architectures
  • specialized power electronics
  • portable power supplies
  • power supplies tailored for photonics and/or RF, mm-wave and/or THz applications
  • power supplies for lighting applications including solid state lighting such as LEDs, OLEDs and quantum dots.
Organic electronics
  • DC and low frequency
  • high frequency
  • novel designs and architectures
  • passive and active addressable arrays
  • low power
  • modulated configurations
  • sensing, detection and/or emitting
  • organic light emitting diodes and associated electronics
  • lighting therapy using solid state lighting including OLEDs.

Wednesday, 24 May 2017

Structural changes of Bombyx mori fibroin from silk gland to fiber as evidenced by Terahertz spectroscopy and other methods

Wu, Xu, Xiaodong Wu, Min Shao, and Bin Yang. "Structural changes of Bombyx mori fibroin from silk gland to fiber as evidenced by Terahertz spectroscopy and other methods." International Journal of Biological Macromolecules (2017).

Abstract
Here we investigated the structural changes of silk fibroin during Bombyx mori silkworm spinning and reconstitution process. X-ray diffraction, Fourier transform infrared spectroscopy, polarized optical microscopy, and terahertz (THz) spectroscopy were applied to monitor the structural features of silk fibroin from posterior, middle silk glands, to cocoons, and then to reconstituted silk. Results show that from silk gland to cocoon, fibroin experiences a significant transformation in crystal structure from a typical silk I, to a silk I-rich mixed structure, and finally to a typical silk II state, accompanied with a change in secondary structure from α-helix and random coil structures to preferential orientation β-sheets. Compared with natural silk fibroins, the reconstituted silk fibroin lacks β-sheet conformation and orientation crystallization. Terahertz spectroscopy readily follows these silk fibroin structural changes. Two characteristic peaks for silk fibroin is observed in 2–10 THz. Their strength ratio is strongly correlated with the β-sheet conformation. The absorbance properties in 0.2–2.0 THz also significantly change as a function of changing their crystal structures caused by diverse sources. All of these observations will help in the study of overall structure in silk fibroin to understand more completely the fibroin assembly process in natural spinning and reconstitution process.

for full paper see http://www.sciencedirect.com/science/article/pii/S0141813017311303


... THz spectra in the frequency range of 0.2-2.5 THz were recorded on a TPS spectra 3000 (TeraView Ltd., UK) equipped with an Erbium-doped fiber laser  ...


for more information about TeraView see http://www.azom.com/equipment-details.aspx?EquipID=4411