We experimentally study the thickness dependence of the terahertz (THz) response in {110}-oriented GaAs crystals for free space electro-optic sampling at 1.55 microm. The THz response bandwidths are analyzed and simulated under phase-matching condition with a model frequency response function. The results indicate that the detection bandwidth increases from 2 THz to 3 THz when the thickness of GaAs is reduced from 2 mm to 1 mm. Below 1 mm, the detected bandwidth is increasingly limited by the emitter characteristics and the finite probe pulse duration. The broadest bandwidth in experiment reaches 3.3 THz when using a 0.2 mm thick crystal, while it exceeds 5 THz in theory. The THz response sensitivity was studied experimentally and modeled taking into account the absorption of the THz radiation in the GaAs crystal. While absorption was found to be negligible for the crystal thickness range studied here, strong saturation is predicted theoretically for crystal thicknesses exceeding 5 mm.
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http://dx.doi.org/10.1364/OE.18.015956 | DOI Listing |
Sensors (Basel)
January 2025
Department of Information Engineering, Electronics and Telecommunications (DIET), "La Sapienza" University of Rome, 00184 Rome, Italy.
This research proposes an all-metal metamaterial-based absorber with a novel geometry capable of refractive index sensing in the terahertz (THz) range. The structure consists of four concentric diamond-shaped gold resonators on the top of a gold metal plate; the resonators increase in height by 2 µm moving from the outer to the inner resonators, making the design distinctive. This novel configuration has played a very significant role in achieving multiple ultra-narrow resonant absorption peaks that produce very high sensitivity when employed as a refractive index sensor.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
New Cornerstone Science Laboratory, Tsinghua-Peking Joint Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
The technology of native chemical ligation and postligation desulfurization has greatly expanded the scope of modern chemical protein synthesis. Here, we report that ultrasonic energy can trigger robust and clean protein desulfurization, and we developed an ultrasound-induced desulfurization (USID) strategy that is simple to use and generally applicable to peptides and proteins. The USID strategy involves a simple ultrasonic cleaning bath and an easy-to-use and easy-to-remove sonosensitizer, titanium dioxide.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Advanced Micro-/Nano- Devices Lab, Department of Systems Design Engineering, University of Waterloo, 200 University Ave West, Waterloo, Ontario N2L 3G1, Canada.
Existing biomedical imaging modalities are often restricted by their substantial size, high costs, and potential risks associated with ionizing radiation exposure. Given these challenges, there is an urgent need for innovative imaging systems that not only excel in detection performance but are also compact, cost-effective, and ensure safety for biomedical applications. In response to these requirements, our research introduces an advanced terahertz (THz) microbolometer array imaging system (MAIS), specifically engineered for biomedical detection.
View Article and Find Full Text PDFBiochim Biophys Acta Mol Cell Biol Lipids
January 2025
Budker Institute of Nuclear Physics SB RAS, Acad. Lavrentiev Ave.,9, 630090 Novosibirsk, Russia.
Terahertz (THz) radiation has gained attention due to technological advancements, but its biological effects remain unclear. We investigated the impact of 2.3 THz radiation on SK-MEL-28 cells using metabolomic and gene network analysis.
View Article and Find Full Text PDFACS Photonics
January 2025
Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (FORTH-IESL), GR-70013 Heraklion, Crete, Greece.
THz metamaterials present unique opportunities for next-generation technologies and applications as they can fill the "THz gap" originating from the weak response of natural materials in this regime, providing a variety of novel or advanced electromagnetic wave control components and systems. Here, we propose a novel metamaterial design made of three-dimensional, metallic, "cactus-like" meta-atoms, showing electromagnetically induced transparency (EIT) and enhanced refractive index sensing performance at low THz frequencies. Following a detailed theoretical analysis, the structure is realized experimentally using multiphoton polymerization and electroless silver plating.
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