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Investigation of optimal THz band for corneal water content quantification
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Baggio M., Tamminen A., Presnyakov S., Kravchenko N., Nefedova I., Ala-laurinaho J., Brown E., Deng S., Wallace V., Taylor Z.
Terahertz imaging and sensing is currently being explored as a method for corneal disease detection as systems operating in this spectrum are sensitive to corneal-water content and thickness. The free-space wavelength of the low-frequency THz band is close to the typical human corneal central thickness (CCT, 540 μm) and the water content is distributed in an approximately linear gradient increasing from anterior (front) to posterior (back). The cornea presents as a lossy thin film at THz frequencies, thus the resolution of longitudinal modes via broadband reflectometry should allow for the extraction of thickness, corneal anterior water content (CAWC) and corneal posterior water content (CPWC) [1] . The implementation of this sensing technology requires identification of an optimal THz frequency band.
Shurakov A., Lvov A., Belikov I. et al., , in: 2024 IEEE 9th All-Russian Microwave Conference (RMC).: IEEE, 2024. P. 196–199.
Terahertz frequency range attracts the attention of the scientific community in different fields, including data transfer, imaging, and spectral analysis. In the context of astronomical instrumentation, the utilization of the 7–14 THz spectral band opens up opportunities for advanced studies of exoplanet formation and the energy balance in the interstellar medium from the Earth surface. ...
Added: January 24, 2025
Prikhodko A., Khakimov A., Mokrov E. et al., Lecture Notes in Computer Science 2024 Vol. 14123 P. 423–434
The future 6G cellular systems are expected to utilize the lower part of the terahertz frequency band, 100–300 GHz. As a result of high path losses, the coverage of such systems will be limited to a few tens of meters making them suitable for indoor environments. As compared to outdoor deployments, indoor usage of THz systems ...
Added: September 25, 2024
Khakimov A., Prikhodko A., Mokrov E. et al., Lecture Notes in Computer Science 2024 Vol. 14542 P. 181–193
Blockage detection is a critical functionality for the air interface in modern 5G and future 6G systems operating in millimeter wave (mmWave, 30–300 GHz) and terahertz (0.3–3 THz) frequency bands. In operational systems, blockage has to be detected prior to its occurrence to allow for time to take some actions to avoid the loss of ...
Added: September 25, 2024
Kirill Shein, Zharkova E., Kashchenko M. et al., Nano Letters 2024 Vol. 24 No. 7 P. 2282–2288
The rapid development of infrared spectroscopy, observational astronomy, and scanning near-field microscopy has been enabled by the emergence of sensitive mid- and far-infrared photodetectors. Superconducting hot-electron bolometers (HEBs), known for their exceptional signal-to-noise ratio and fast photoresponse, play a crucial role in these applications. While superconducting HEBs are traditionally crafted from sputtered thin films such ...
Added: February 13, 2024
Gayduchenko I., M.: Our Style, 2023.
The abstracts of reports of the 5th International Conference “Terahertz and Microwave Radiation: Generation, Detec- tion and Applications” (TERA-2023). TERA-2023 conference is devoted to the discussion of fundamental and applied problems related to the generation and detection of terahertz and microwave radiation as well as its interaction with matter. The purpose of the conference is ...
Added: February 12, 2024
Shurakov A., Belikov I., Prikhodko A. et al., Applied Sciences (Switzerland) 2023 Vol. 13 No. 10 Article 5892
Terahertz photonic integrated circuits are becoming popular in ultrafast on-chip signal generation and processing. They outperform assemblies of electronic devices making use of metallic waveguides in term of both fabrication complexity and system losses. In this study, we report on a nearly all-dielectric hot electron bolometer mixer compatible with the technology of integrated Si photonic ...
Added: May 11, 2023
E. Khorov, A. Krasilov, M. Susloparov et al., IEEE Communications Surveys and Tutorials 2023 Vol. 25 No. 4 P. 2862–2891
Emerging wireless systems target to provide multi-Gbps data rates for each user, which can be achieved by utilizing ultra-wide channels available at mmWave, terahertz, and lightwave frequencies. In contrast to the traditional spectrum below 6 GHz, these high-frequency bands raise many issues, complicating their usage. For example, because of high signal attenuation and blockage by ...
Added: December 23, 2022
Stepanov N., Moltchanov D., Begishev V. et al., IEEE Transactions on Vehicular Technology 2022 Vol. 71 No. 1 P. 725–738
Terahertz (THz, 0.3!!-!!3 THz) wireless access is nowadays considered as a major enabling technology for sixth generation (6G) cellular systems. To compensate for high propagation losses, these systems will utilize antenna arrays with extremely directional beams. The performance of such systems will thus be heavily affected by micromobility such as shakes and rotations of user ...
Added: October 27, 2022
Vinnichenko M. Y., Makhov I., Ustimenko R. V. et al., , in: 2022 47th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz).: IEEE, 2022. P. 1–2.
Added: October 25, 2022
Baggio M., Tamminen A., Presnyakov S. et al., , in: Optics InfoBase Conference Papers.: The Optical Society, 2021.
Added: December 14, 2021
Makhov I. S., Panevin V. Y., Firsov D. A. et al., Journal of Luminescence 2019 Vol. 210 P. 352–357
The low-temperature terahertz and near-infrared photoluminescence from the near-infrared laser nanostructure with GaAs/AlGaAs quantum wells doped with shallow donors is studied under intense interband optical excitation. The optical electron transitions involving excited and ground donor states in quantum wells are revealed in terahertz and near-infrared photoluminescence spectra. Impurity assisted near-infrared stimulated emission under interband optical ...
Added: October 15, 2021
Gayduchenko I., Xu S. G., Alymov G. et al., Nature Communications 2021 Vol. 12 No. 1 Article 543
The rectification of electromagnetic waves to direct currents is a crucial process for energy harvesting, beyond-5G wireless communications, ultra-fast science, and observational astronomy. As the radiation frequency is raised to the sub-terahertz (THz) domain, ac-to-dc conversion by conventional electronics becomes challenging and requires alternative rectification protocols. Here, we address this challenge by tunnel field-effect transistors ...
Added: September 27, 2021
Tamminen A., Baggio M., Nefedova I. et al., IEEE Transactions on Terahertz Science and Technology 2021 Vol. 11 No. 6 P. 647–659
Absolute thickness and free water content gradients in gelatin-based corneal phantoms with physiologically accurate radii of curvature, and aqueous backing were extracted via coherent submillimeter wave reflectometry at 220 330 GHz. Fourier-domain based calibration methods, utilizing temporal and spatial gating, were developed and yielded peak-to-peak amplitude and phase clutter of 10-3 and 0.1, respectively for ...
Added: September 14, 2021
Petrov V., M. Komarov, D. Moltchanov et al., IEEE Transactions on Wireless Communications 2017 Vol. 16 No. 3 P. 1791–1808
The fifth generation wireless systems are expected to rely on a large number of small cells to massively offload traffic from the cellular and even from the wireless local area networks. To enable this functionality, mm-wave (EHF) and Terahertz (THF) bands are being actively explored. These bands are characterized by unique propagation properties compared with ...
Added: March 12, 2018
Ozhegov R., Gorshkov K. N., Goltsman G. et al., Superconductor Science and Technology 2011 Vol. 24 No. 3 P. 1–4
We present the results of stability testing of a terahertz radiometer based on a superconducting receiver with a SIS tunnel junction as the mixer and a flux-flow oscillator as the local oscillator. In the continuum mode, the receiver with a noise temperature of 95 K at 510 GHz measured over the intermediate frequency (IF) passband ...
Added: October 12, 2017
Iomdina E., Goltsman G., Seliverstov S. et al., Journal of Biomedical Optics 2016 Vol. 21 No. 9 P. 097002
An adequate water balance (hydration extent) is one of the basic factors of normal eye function, including its external shells: the cornea and the sclera. Adequate control of corneal and scleral hydration is very important for early diagnosis of a variety of eye diseases, stating indications for and contraindications against keratorefractive surgeries and the choice ...
Added: October 19, 2016
Komarov M. M., , in: Proceedings of the 17th IEEE Conference on Business Informatics (CBI 2015).: Los Alamitos: IEEE Computer Society, 2015. Ch. 1 P. 27–36.
Big data is a term used to describe data sets so large and/or complex that traditional data processing algorithms and applications are inadequate. There are numerous challenges when handling these data including analysis, capture, search, sharing, storage, transfer, visualization and privacy. A significant portion of big data is expected to be generated by special types ...
Added: September 19, 2015