TechXplore February 1, 2021 Researchers in Japan configured a two-channel terahertz transmitter (Tx) by modulating the output of a laser pair with wavelengths in the 1.55-micron band, which was set so that the frequency difference was in the 300-GHz band, with an 8K video signal source using an intensity modulator and converting it into terahertz waves using an ultrafast photodiode. After the wirelessly transmitted terahertz waves were detected by sensitive terahertz coherent receivers (Rxs) using resonant tunnel diodes (RTDs) they were split from the two channels into four channels and connected to an 8K monitor via HDMI cable. Using this […]
Tag Archives: S&T Japan
Atomic-scale nanowires can now be produced at scale
Phys.org December 24, 2020 Transition-metal chalcogenide (TMC) nanowires, which are one-dimensional structures having three-atom diameters and van der Waals surfaces, have been reported to possess a 1D metallic nature with great potential in electronics and energy devices. To mass produce TMC researchers in Japan have demonstrated a wafer-scale synthesis of highly crystalline transition-metal telluride nanowires by chemical vapor deposition. The technique enables formation of either aligned, atomically thin two-dimensional (2D) sheets or random networks of three-dimensional (3D) bundles, both composed of individual nanowires. These nanowires exhibit an anisotropic 1D optical response and superior conducting properties. The findings not only shed […]
Extremely energy efficient microprocessor developed using superconductors
EurekAlert December 28, 2020 Using the adiabatic quantum-flux-parametron (AQFP), as a building block researchers in Japan have developed and demonstrated a prototype 4-bit AQFP microprocessor called MANA (Monolithic Adiabatic iNtegration Architecture). The AQFP is capable of data processing and data storage, it can operate up to a clock frequency of 2.5 GHz making this on par with today’s computing technologies. They expect this to increase to 5-10 GHz as they make improvements in design methodology and experimental setup. According to the researchers even when taking this cooling overhead into account, the AQFP is still about 80 times more energy-efficient when […]
New quantum nanodevice can simultaneously act as a heat engine and a refrigerator
Phys.org December 28, 2020 An international team of researchers (Japan, Ukraine, USA – University of Michigan) has experimentally demonstrated the quantum version of the heat engine which uses an electron in a transistor. The electron has two possible energy states. The team could increase or decrease the gap between these energy states by applying an electric field and microwaves. This can be analogous to the periodic expanding–compressing operation of a fluid in a chamber. The device also emitted microwaves when the electron went from the high-energy level to the lower one. By monitoring whether the upper energy level was occupied, […]
Shapeshifting crystals: Varying stability in different forms of gallium selenide monolayers
Phys.org December 24, 2020 Gallium selenide monolayer has been recently discovered to have an alternative crystal structure and has diverse potential applications in electronics. Researchers in Japan studied the structural stability and electronic states of GaSe monolayer with trigonal-antiprismatic (AP) structure by first-principles calculations. The AP-phase GaSe monolayer was found stable, and the differences in energy and lattice constant were small when compared to those calculated for a GaSe monolayer with conventional trigonal-prismatic (P) structure which was found to be the ground state. Moreover, it was revealed that the relative stability of P-phase and AP-phase GaSe monolayers reverses under tensile […]
Toward imperceptible electronics that you cannot see or feel
Phys.org December 14, 2020 Transparent electronics—such as head-up displays that allow pilots to read flight data while keeping their eyes ahead of them. For healthcare applications the electronics should be sufficiently flexible to conform to skin. Although silver nanowire networks meet these criteria, the current methods of development create random nanowire alignment that is insufficient for advanced applications. Researchers in Japan used high-resolution printing to fabricate centimeter-scale cross-aligned silver nanowire arrays, with reproducible feature sizes from 20 to 250 micrometers. The microelectrodes-based organic field-effect transistors exhibited excellent multi-functionality. The sheets were well-suited for transparent electronics. As a proof-of-concept for functionality, […]
World’s First Successful Transmission of 1 Petabit per Second Using a Single-core Multimode Optical Fiber
NICT Japan December 18, 2020 Researchers in Japan have demonstrated the possibility of combining highly spectral efficient wideband optical transmission with an optical fiber guiding 15 fiber modes that had a cladding diameter in agreement with the current industry standard of 0.125 mm. This was enabled by mode multiplexers and an optical fiber that supported wideband transmission of more than 80 nm over 23 km. The study highlights the large potential of single-core multi-mode fibers for high-capacity transmission using fiber manufacturing processes like those used in the production of standard multi-mode fibers. The results of this study were accepted for […]
Within a hair’s breadth–forensic identification of single dyed hair strand now possible
EurekAlert December 9, 2020 Researchers in Japan developed a strategy for identifying criminals from a single strand of hair, leveraging the fact that hair dyes are becoming increasingly common. Their approach involves finding out if two individual strands of hair belong to the same person based on the composition of hair dye products found on them. They used surface-enhanced Raman spectroscopy (SERS) and X-ray fluorescence (XRF) analysis. SERS can easily detect the overall differences in composition between different types of hair dyes, such as permanent, semi-permanent, or natural dyes. However, it is not enough to distinguish between hair coloring products […]
Molecules convert visible light into ultraviolet light with record efficiency
EurekAlert December 4, 2020 To directly convert visible light with wavelengths longer than 400 nm into higher-energy ultraviolet light researchers in Japan focused on triplet-triplet annihilation where triplets are formed on molecules following absorption of visible light. These “donor” molecules then give their triplets to “acceptor” molecules that can combine two triplets to create a single, higher-energy state that is released as ultraviolet light. They developed an acceptor molecule TIPS-naphthalene that has a high triplet-triplet-annihilation efficiency and a low enough triplet energy to easily accept triplets from a molecule called Ir(C6)2(acac). The combination of TIPS-naphthalene and Ir(C6)2(acac) successfully achieved the […]
Improving quantum dot interactions, one layer at a time
Science Daily November 20, 2020 Controlling interaction between quantum dots could greatly improve charge transport, leading to more efficient solar cells. Researchers fabricated CdTe quantum dot superlattices via the layer-by-layer assembly of positively charged polyelectrolytes and negatively charged CdTe quantum dots to control the dimension of the quantum resonance by independently changing the distances between quantum dots in the stacking (out-of-plane) and in-plane directions. They experimentally verified the miniband formation. The fabrication method can be used with other types of water-soluble quantum dots and nanoparticles. Combining different types of semiconductor quantum dots, or combining semiconductor quantum dots with other nanoparticles, […]