T-Ray Sensing and Imaging

Terahertz (THz) radiation occupies part of the electromagnetic spectrum between the infrared and microwave bands. Until recently, technology at THz frequencies was under-developed compared to the rest of the electromagnetic spectrum, leaving a gap between millimeter waves and the far-infrared (FIR). In the past decade, interest in the THz gap has been increased by the development of ultrafast laser-based T-ray systems and their demonstration of diffraction-limited spatial resolution, picosecond temporal resolution, DC-THz spectral bandwidth and signal-to-noise ratios above 104. This chapter reviews the development, the state of the art and the applications of T-ray spectrometers. Continuous-wave (CW) THz-frequency sources and detectors are briefly introduced in comparison to ultrafast pulsed THz systems. An emphasis is placed on experimental applications of T-rays to sensing and imaging, with a view to the continuing advance of technologies and applications in the THz band.

Download Full-text

Celebrating 30 years of science from the James Clerk Maxwell Telescope

Royal Society Open Science ◽

10.1098/rsos.170754 ◽

2017 ◽

Vol 4 (9) ◽

pp. 170754

Author(s):

Ian Robson ◽

Wayne S. Holland ◽

Per Friberg

Keyword(s):

State Of The Art ◽

Large Fraction ◽

Far Infrared ◽

Review Article ◽

Single Element ◽

James Clerk Maxwell ◽

The Past ◽

Look Back ◽

Infrared Background ◽

Nearby Stars

The James Clerk Maxwell Telescope (JCMT) has been the world’s most successful single-dish telescope at submillimetre wavelengths since it began operations in 1987. From the pioneering days of single-element photometers and mixers, through to the state-of-the-art imaging and spectroscopic cameras, the JCMT has been associated with a number of major scientific discoveries. Famous for the discovery of ‘SCUBA’ galaxies, which are responsible for a large fraction of the far-infrared background, the JCMT has pushed the sensitivity limits arguably more than any other facility in this most difficult of wavebands in which to observe. Closer to home, the first images of huge discs of cool debris around nearby stars gave us clues to the evolution of planetary systems, further evidence of the importance of studying astrophysics in the submillimetre region. Now approaching the 30th anniversary of the first observations, the telescope continues to carry out unique and innovative science. In this review article, we look back on some of the major scientific highlights from the past 30 years.

Download Full-text

Non-scanning systems for far-infrared radiation detection from laser-induced plasmas

High Power Laser Science and Engineering ◽

10.1017/hpl.2015.10 ◽

2015 ◽

Vol 3 ◽

Cited By ~ 2

Author(s):

Chun Li ◽

Guo-Qian Liao ◽

Yu-Tong Li

Keyword(s):

State Of The Art ◽

Radiation Detection ◽

Far Infrared ◽

Detection Methods ◽

Thz Radiation ◽

Single Shot ◽

Laser Plasma Interactions ◽

Shot Detection ◽

Laser Systems ◽

Scanning Systems

With the development of ultraintense terawatt (TW) and petawatt (PW) laser systems, powerful terahertz (THz) radiation from laser–plasma interactions has been reported. Plasma-based THz systems, which are usually operated at extremely low repetition rates, call for single-shot diagnostics. In this paper, various state-of-the-art single-shot detection methods are introduced or designed for measurements and applications involved in high-power plasma-based THz sciences.

Download Full-text

Intersubband Rabi Oscillations in Asymmetric Nanoheterostructures: Implications for a Tunable Continuous-Wave Source of a Far-Infrared and THz Radiation

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2012.6221 ◽

2012 ◽

Vol 12 (6) ◽

pp. 4650-4657

Author(s):

V. A. Kukushkin

Keyword(s):

Continuous Wave ◽

Far Infrared ◽

Thz Radiation ◽

Rabi Oscillations ◽

Wave Source

Download Full-text

A Macintosh Interface for the Cameca Camebax-Micro Electron Microprobe

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010018094x ◽

1990 ◽

Vol 48 (1) ◽

pp. 438-439

Author(s):

Carl E. Henderson

Keyword(s):

Electron Microprobe ◽

Processing Speed ◽

Word Processing ◽

State Of The Art ◽

Computer Control ◽

Third Party ◽

Disk Storage ◽

The Past ◽

User Facility ◽

Instrument Control

Over the past few years it has become apparent in our multi-user facility that the computer system and software supplied in 1985 with our CAMECA CAMEBAX-MICRO electron microprobe analyzer has the greatest potential for improvement and updating of any component of the instrument. While the standard CAMECA software running on a DEC PDP-11/23+ computer under the RSX-11M operating system can perform almost any task required of the instrument, the commands are not always intuitive and can be difficult to remember for the casual user (of which our laboratory has many). Given the widespread and growing use of other microcomputers (such as PC’s and Macintoshes) by users of the microprobe, the PDP has become the “oddball” and has also fallen behind the state-of-the-art in terms of processing speed and disk storage capabilities. Upgrade paths within products available from DEC are considered to be too expensive for the benefits received. After using a Macintosh for other tasks in the laboratory, such as instrument use and billing records, word processing, and graphics display, its unique and “friendly” user interface suggested an easier-to-use system for computer control of the electron microprobe automation. Specifically a Macintosh IIx was chosen for its capacity for third-party add-on cards used in instrument control.

Download Full-text

Broadband spectroscopy of astrophysical ice analogues

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935619 ◽

2019 ◽

Vol 629 ◽

pp. A112 ◽

Cited By ~ 8

Author(s):

B. M. Giuliano ◽

A. A. Gavdush ◽

B. Müller ◽

K. I. Zaytsev ◽

T. Grassi ◽

...

Keyword(s):

Refractive Index ◽

Optical Properties ◽

Time Domain ◽

Complex Refractive Index ◽

Far Infrared ◽

Infrared Region ◽

Thz Radiation ◽

The Real ◽

Thz Range ◽

The Time Domain

Context. Reliable, directly measured optical properties of astrophysical ice analogues in the infrared and terahertz (THz) range are missing from the literature. These parameters are of great importance to model the dust continuum radiative transfer in dense and cold regions, where thick ice mantles are present, and are necessary for the interpretation of future observations planned in the far-infrared region. Aims. Coherent THz radiation allows for direct measurement of the complex dielectric function (refractive index) of astrophysically relevant ice species in the THz range. Methods. We recorded the time-domain waveforms and the frequency-domain spectra of reference samples of CO ice, deposited at a temperature of 28.5 K and annealed to 33 K at different thicknesses. We developed a new algorithm to reconstruct the real and imaginary parts of the refractive index from the time-domain THz data. Results. The complex refractive index in the wavelength range 1 mm–150 μm (0.3–2.0 THz) was determined for the studied ice samples, and this index was compared with available data found in the literature. Conclusions. The developed algorithm of reconstructing the real and imaginary parts of the refractive index from the time-domain THz data enables us, for the first time, to determine the optical properties of astrophysical ice analogues without using the Kramers–Kronig relations. The obtained data provide a benchmark to interpret the observational data from current ground-based facilities as well as future space telescope missions, and we used these data to estimate the opacities of the dust grains in presence of CO ice mantles.

Download Full-text

Multifunctional Optical Crystals for All-Solid-State Raman Lasers

Crystals ◽

10.3390/cryst11020114 ◽

2021 ◽

Vol 11 (2) ◽

pp. 114

Author(s):

Hui Zhao ◽

Shibo Dai ◽

Siqi Zhu ◽

Hao Yin ◽

Zhen Li ◽

...

Keyword(s):

Solid State ◽

Continuous Wave ◽

Frequency Doubling ◽

Raman Laser ◽

Rare Earth Ions ◽

Excellent Performance ◽

The Past ◽

Raman Lasers ◽

Optical Crystals ◽

Laser Crystals

In the past few decades, the multifunctional optical crystals for all-solid-state Raman lasers have been widely studied by many scholars due to their compactness, convenience and excellent performance. In this review, we briefly show two kinds of multifunctional Raman crystals: self-Raman (laser and Raman effects) crystals and self-frequency-doubled Raman (frequency-doubling and Raman effects) crystals. We firstly introduce the properties of the self-Raman laser crystals, including vanadate, tungstate, molybdate and silicate doped with rare earth ions, as well as self-frequency-doubled Raman crystals, including KTiOAsO4 (KTA) and BaTeMo2O9 (BTM). Additionally, the domestic and international progress in research on multifunctional Raman crystals is summarized in the continuous wave, passively Q-switched, actively Q-switched and mode-locked regimes. Finally, we present the bottleneck in multifunctional Raman crystals and the outlook for future development. Through this review, we contribute to a general understanding of multifunctional Raman crystals.

Download Full-text

Inflammation, epigenetics, and metabolism converge to cell senescence and ageing: the regulation and intervention

Signal Transduction and Targeted Therapy ◽

10.1038/s41392-021-00646-9 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Xudong Zhu ◽

Zhiyang Chen ◽

Weiyan Shen ◽

Gang Huang ◽

John M. Sedivy ◽

...

Keyword(s):

Cell Fate ◽

Cellular Response ◽

State Of The Art ◽

Cell Senescence ◽

Therapeutic Interventions ◽

Cell Fate Decision ◽

The Past ◽

Fate Decision ◽

The Individual ◽

Remarkable Progress

AbstractRemarkable progress in ageing research has been achieved over the past decades. General perceptions and experimental evidence pinpoint that the decline of physical function often initiates by cell senescence and organ ageing. Epigenetic dynamics and immunometabolic reprogramming link to the alterations of cellular response to intrinsic and extrinsic stimuli, representing current hotspots as they not only (re-)shape the individual cell identity, but also involve in cell fate decision. This review focuses on the present findings and emerging concepts in epigenetic, inflammatory, and metabolic regulations and the consequences of the ageing process. Potential therapeutic interventions targeting cell senescence and regulatory mechanisms, using state-of-the-art techniques are also discussed.

Download Full-text

Security assurance cases—state of the art of an emerging approach

Empirical Software Engineering ◽

10.1007/s10664-021-09971-7 ◽

2021 ◽

Vol 26 (4) ◽

Author(s):

Mazen Mohamad ◽

Jan-Philipp Steghöfer ◽

Riccardo Scandariato

Keyword(s):

State Of The Art ◽

Tool Support ◽

Security Assurance ◽

The Past ◽

Depth Analysis ◽

Structured Argumentation ◽

Security Properties ◽

Standards And Regulations ◽

Assurance Cases ◽

Security Standards

AbstractSecurity Assurance Cases (SAC) are a form of structured argumentation used to reason about the security properties of a system. After the successful adoption of assurance cases for safety, SAC are getting significant traction in recent years, especially in safety-critical industries (e.g., automotive), where there is an increasing pressure to be compliant with several security standards and regulations. Accordingly, research in the field of SAC has flourished in the past decade, with different approaches being investigated. In an effort to systematize this active field of research, we conducted a systematic literature review (SLR) of the existing academic studies on SAC. Our review resulted in an in-depth analysis and comparison of 51 papers. Our results indicate that, while there are numerous papers discussing the importance of SAC and their usage scenarios, the literature is still immature with respect to concrete support for practitioners on how to build and maintain a SAC. More importantly, even though some methodologies are available, their validation and tool support is still lacking.

Download Full-text

The state of the art in soybean transcriptomics resources and gene coexpression networks

in silico Plants ◽

10.1093/insilicoplants/diab005 ◽

2021 ◽

Author(s):

Fabricio Almeida-Silva ◽

Kanhu C Moharana ◽

Thiago M Venancio

Keyword(s):

State Of The Art ◽

The State ◽

Gene Coexpression Network ◽

Rna Seq ◽

Transcriptomic Data ◽

The Past ◽

Gene Coexpression ◽

Genomics Research ◽

Public Repositories ◽

Coexpression Networks

Abstract In the past decade, over 3000 samples of soybean transcriptomic data have accumulated in public repositories. Here, we review the state of the art in soybean transcriptomics, highlighting the major microarray and RNA-seq studies that investigated soybean transcriptional programs in different tissues and conditions. Further, we propose approaches for integrating such big data using gene coexpression network and outline important web resources that may facilitate soybean data acquisition and analysis, contributing to the acceleration of soybean breeding and functional genomics research.

Download Full-text