Observation of giant room-temperature anisotropic magnetoresistance in the topological insulator β-AgTe.

Achieving room-temperature high anisotropic magnetoresistance ratios is highly desirable for magnetic sensors with scaled supply voltages and high sensitivities. However, the ratios in heterojunction-free thin films are currently limited to only a few percent at room temperature. Here, we observe a high anisotropic magnetoresistance ratio of -39% and a giant planar Hall effect (520 μΩ⋅cm) at room temperature under 9 T in β-AgTe crystals grown by chemical vapor deposition.

Advancing Sensitivity in Guided-Wave Surface Plasmon Resonance Sensor through Integration of 2D BlueP/MoS Hybrid Layers.

The surface plasmon resonance (SPR) signal, generated from the Kretschmann configuration, has been developed as an effective detection technology in chemical and biological sensors. The sensitivity of SPR signals to changes in the surrounding media makes it a valuable tool, as even a slight variation in refractive index can cause a significant change in SPR signals, such as phase, intensity, and resonance angle. However, the detection of ultralow changes in refractive index, which occur in chemical reactions or biological actions, remains a challenge for conventional SPR sensors due to their limited sensitivity.

High-efficiency Ge-based waveguide photodetector integrated with a grating coupler on silicon-on-insulator.

We propose the design of a composite device structure with germanium-based (Ge-based) waveguide photodetectors integrated with grating couplers on a silicon-on-insulator platform. The finite-difference time-domain method is used to establish simulation models and optimize the design of the waveguide detector and grating coupler. For the grating coupler, by adjusting the size parameters to the optimal value and combining the advantages of the nonuniform grating and the Bragg reflector structure, the peak coupling efficiency reaches 85% at 1550 nm and 75.

Influence of metal-semiconductor junction on the performances of mixed-dimensional MoS/Ge heterostructure avalanche photodetector.

The two-dimensional/three-dimensional van der Waals heterostructures provide novel optoelectronic properties for the next-generation of information devices. Herein, MoS/Ge heterojunction avalanche photodetectors are readily obtained. The device with an Ag electrode at MoS side exhibits more stable rectification characteristics than that with an Au electrode.

Severity Assessment of COVID-19 Based on Feature Extraction and V-Descriptors.

Digital image feature recognition is significant to industrial information applications, such as bioengineering, medical diagnosis, and machinery industry. In order to supply an effective and reasonable technology of the severity assessment mission of coronavirus disease (COVID-19), in this article, we propose a new method that identifies rich features of lung infections from a chest computed tomography (CT) image, and then assesses the severity of COVID-19 based on the extracted features. First, in a chest CT image, the lung contours are corrected for the segmentation of bilateral lungs.

Recent Advances of Spatial Self-Phase Modulation in 2D Materials and Passive Photonic Device Applications.

Optical nonlinearity in 2D materials excited by spatial Gaussian laser beam is a novel and peculiar optical phenomenon, which exhibits many novel and interesting applications in optical nonlinear devices. Passive photonic devices, such as optical switches, optical logical gates, photonic diodes, and optical modulators, are the key compositions in the future all-optical signal-processing technologies. Passive photonic devices using 2D materials to achieve the device functionality have attracted widespread concern in the past decade.