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Thermal Nanosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
In view of the penetration capability of terahertz radiation through clothes, dust, smoke, and biological materials being better than that of infrared or visible light, terahertz imagers are useful for detecting concealed weapons, illicit drugs, and biological materials. Are HEB devices useful for applications requiring low noise temperatures at frequencies from 0.5 to 10THz? How do they utilize the effect of electron heating by the incoming terahertz radiation? Discuss the salient features of HEB technology.
Introduction—Electricity’s Attributes
Published in Clark W. Gellings, 2 Emissions with Electricity, 2020
Terahertz radiation is a region of the spectrum between infrared and microwaves. Recently, applications such as imaging and communications are appearing in this frequency range. Scientists are also looking to apply terahertz technology in the armed forces, where high-frequency waves might be directed at enemy troops to incapacitate their electronic equipment (Wikipedia—Electromagnetic Spectrum).
Electromagnetic Nanonetworks
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2019
Md. Humaun Kabir, Kyung Sup Kwak
Falling in between infrared radiation and microwave radiation in the electromagnetic spectrum, some properties of terahertz radiation are found to be common with each of these. As in the case of infrared and microwave radiation, terahertz radiation also propagates in a line of sight and is nonionizing. Terahertz radiation can also penetrate a wide variety of nonconducting materials as microwave radiation does. Nonionizing terahertz radiation can pass through clothing, paper, cardboard, wood, masonry, plastic and ceramics. The penetration depth is, in particular, less than that of microwave radiation. Terahertz radiation has limited penetration through fog and clouds and cannot penetrate liquid water or metal. Unlike X-rays, terahertz radiation is not ionizing radiation, and its low photon energies generally do not cause any harm to living tissues and DNA (Deoxyribonucleic acid) (Choudhury, Sonde, & Jha, 2016). It can penetrate some distance through body tissue, so it is of great interest as a replacement for medical X-rays. However, due to its longer wavelength, images made using terahertz have lower resolution than X-rays and need to be enhanced.
Effects of the surrounding medium on terahertz wave scattering loss in intrabody communication
Published in Waves in Random and Complex Media, 2022
As a promising candidate for wireless intrabody communications, terahertz generation and propagation have been under development [9–15]. The viability of terahertz waves for developing a feasible intrabody communication technique has been recently demonstrated [2]. It has been shown that terahertz band could provide more compact and cost-effective alternative approach with relatively less complexity, less energy consumption, higher rate transmission (in order of terabits per second) compared with that at RF frequencies [16]. Moreover, terahertz radiation is expected to significantly contribute to future nanoscale communication compared to the infrared and optical spectral regions. Non-ionizing terahertz waves could provide fingerprint coincidence with molecular resonance, more dependable data quality and time delay, and less susceptibility to propagation losses such as spreading effect and Rayleigh scattering, without hazard consideration for the biological tissues [2, 8, 17–19]. However, the application of terahertz waves for nanocommunication networks would significantly suffer from absorption loss and small transmission time which is comparable with the processing time [8, 20]. Therefore, a complete analysis of terahertz propagation in biological tissues and layers is required to pave the way toward efficient intrabody THz communication.
Three-dimensional modelling and terahertz imaging of malignant cells with convolutional time-reversed FDTD method
Published in Electromagnetics, 2022
Terahertz pulsed imaging (TPI) and spectroscopy (TPS) have a growing interest in biomedical applications such as cancer diagnosis (Ashworth et al. 2009; Fitzgerald et al. 2006; Han, Cho, and Zhang 2000; Markelz 2008; Pickwell et al. 2004; Woodward et al. 2003) and characterization of DNA (Nagel, Först, and Kurz 2006), proteins with intermolecular reactions (Knabet al. 2007), and glucose levels in diabetic’s blood (Chen et al. 2018). Thanks to the unique characteristics of the terahertz region that lies from 0.1 THz to 10 THz (the corresponding wavelength of to ), the terahertz radiation is non-ionizing on healthy tissue, thus making it a future diagnosis method in medical imaging. Developments in terahertz technologies such as designing metamaterial biosensors will influence new generation medical imaging systems (Sugumaran et al. 2018; Zhang et al. 2018). One of the most important features is the low photon energy of the radiation, thereby not causing any ionization, thus resulting in no chemical damage to living cells. Another physical feature of the terahertz signal is its sensitivity to polar materials like water content. Therefore, terahertz imaging provides a higher contrast to soft tissues (Yu et al. 2012). By comparing these features to the X-ray imaging systems, the nondestructive effect of terahertz signals on healthy tissue provides a promising medical imaging technique for the next generation of diagnostic systems.
Dispersion of electromagnetic waves in coaxial cylindrical rippled-wall waveguide including plasma layer
Published in Waves in Random and Complex Media, 2022
F. Asadiamiri, K. Chaudhary, J. Ali, M. Bahadoran, Malihe Nejati, P. P. Yupapin, A. R. Niknam
The applications of electromagnetic fields in the microwave (MW) and terahertz (THz) frequency ranges are of great importance to many areas of engineering and science. The high-power electromagnetic radiation in the terahertz frequency range is used as a source for a variety of technological applications such as terahertz spectroscopy, chemical detection, material characterization, medical and biological imaging, remote sensing, studies of plasmas and the measurement of relativistic electron bunches [1–8]. Therefore, the study of coherent radiations in the THz region is of great importance as compared to lower frequency ranges (radio to microwave) and higher frequency ranges (infrared to visible region). Several mechanisms are used to generate terahertz radiation such as ultra-short intense lasers interaction with plasmas, terahertz free-electron lasers, short single pulse electron beam based sources and by nonlinear optical techniques [9–15].