We demonstrated a high-sensitivity strain sensor based on an in-fiber Fabry-Perot interferometer (FPI) with air cavity, which was created by splicing together two sections of standard single-mode fibers. The sensitivity this enhanced to 6.0 pm/με improving the cavity length FPI means repeating arc discharges for reshaping cavity. Moreover, such has very low temperature 1.1 pm/°C, reduces cross between tensile and temperature.

Abstract We demonstrated a unique rectangular air bubble by means of splicing two sections standard single mode fibers together and tapering the joint. Such an can be used to develop promising high-sensitivity strain sensor based on Fabry-Perot interference. The sensitivity with cavity length about 61 μm wall thickness 1 was measured up 43.0 pm/με is highest among in-fiber FPI-based sensors cavities reported so far. Moreover, our has very low temperature 2.0 pm/°C. Thus, temperature-induced...

We demonstrated a compact and highly-sensitive curvature sensor based on Mach-Zehnder interferometer created in photonic crystal fiber. Such consisted of peanut-like section an abrupt taper achieved by use optimized electrical arc discharge technique, where only one dominating cladding mode was excited interfered with the fundamental mode. The unique structure exhibited high sensitivity 50.5 nm/m-1 within range from 0 to 2.8 m-1, which made it suitable for high-sensitivity sensing harsh...

We demonstrated a high-sensitivity strain sensor based on an inflated long period fiber grating (I-LPFG). The I-LPFG was inscribed, for the first time to best of our knowledge, by use pressure-assisted CO(2) laser beam scanning technique inflate periodically air holes photonic crystal fiber. Such periodic inflations enhanced sensitivity LPFG-based -5.62 pm/με. After high temperature annealing, achieved good repeatability and stability response with 11.92 pm/°C.

Recent advances in the Medical Internet of Things (MIoT) and big data enable a prospering platform for pervasive healthcare facilitate transformation from hospital-centered to human-centered healthcare. Wearable devices as human interfaces provide first-hand real-time monitoring, which are key technologies MIoT. Several remarkable surveys have been conducted summarize recent progress wearable sensors systems MIoT medicine. However, few focused on optical sensing (WOS) technologies, is an...

The fabrication of fiber Bragg gratings was here demonstrated using ultrashort pulse laser point-by-point inscription. This is a very convenient means creating with different grating periods and works by changing the translation speed fiber. energy first optimized in order to improve spectral properties gratings. Then, were formed into D-shaped fibers for use as refractive index sensors. A nonlinear relationship observed between wavelength liquid index, sensitivity ∼30 nm/RIU at 1.450. shows...

Background Early diagnosis of non-union fractures is vital for treatment planning, yet studies using bone morphometric parameters this purpose are scarce. This study aims to create a fracture micro-CT image dataset, design deep learning algorithm segmentation, and develop an early model non-union. Methods Using animal models, images from 12 rats at various healing stages (days 1, 7, 14, 21, 28, 35) were analyzed. Fracture lesion frames annotated high-resolution dataset. We proposed the...

We demonstrate a highly birefringent phase-shifted fiber Bragg grating (PS-FBG) inscribed in H2-free with near-infrared femtosecond Gaussian laser beam and uniform phase mask. The PS-FBG was fabricated from an ordinary (FBG) case which overexposure applied. spectral evolution FBG to FS-FBG observed experimentally decrease transmission loss at dip wavelength, blueshift of the cladding mode loss, increase insertion loss. A high birefringence demonstrated existence only TM polarization....

Continuous respiratory monitoring is extensively important in clinical applications. To effectively assess respiration rate (RR), tidal volume (TV), and minute ventilation (MV), we propose experimentally demonstrate a system using an in-line few-mode fiber Mach-Zehnder interferometer (FMF-MZI), which the first to introduce MZI into optimal wearable design for monitoring. The linear region of proposed sensor analyzed positioned by flexible arch structure with curvature sensitivity up 8.53...

Active control of metasurfaces has attracted widespread attention because the adjustable electromagnetic properties obtained. Here we designed and experimentally studied a dynamically controllable polarization converter in terahertz band. By designing structural parameters utilizing insulator-to-metal phase transition vanadium dioxide principle current resonance, dynamic tunability conversion function from dual-broadband (0.45∼0.77 THz 0.97∼1.2 THz) to ultra-broadband (0.38∼1.20 can be...

Rationale The volatile organic compounds (VOCs) of Lonicerae Japonicae flos (LJF) and Lonicera (LF) play a pivotal role in determining their sensory characteristics, medicinal properties, subsequent impact on market pricing consumer preferences. However, the differences specificity these VOCs remain obscure. Hence, it is crucial to conduct comprehensive characterization LJF LF pinpoint potential differential VOCs. Methods In this study, headspace gas chromatography–ion mobility spectrometry...

Electric power operation, as one of the key fields in world, faces particularly prominent safety issues. Ensuring operators has become most fundamental requirement operation. However, there are some hazards construction. These mainly due to weak awareness among staff and failure standardize wearing helmets. In order effectively address this situation, technical means such video surveillance technology computer vision can be utilized monitor whether helmets provide timely feedback. Such...

We demonstrated a fast mechanical wheel lapping technique to fabricate convenient and low-cost side-polished fiber (SPF) with rough, rather than smooth, polished surface. Such bare SPF can be directly used develop promising sensing device, because Mach-Zehnder interference pattern high fringe contrast above 10 dB in transmission spectrum was achieved due the macro scratches on rough Fabrication parameters, e.g., thickness of remaining fiber, length, roughness abrasive paper, were optimized....

We demonstrate a simple, robust, and highly sensitive temperature sensor based on the resonant excitation of whispering gallery modes in coated single-mode fiber (SMF) loop that was created by means bending standard SMF into with radius 5 mm. Clear interference fringes were observed transmission spectrum coated-SMF loop. The wavelength exhibits linear response at range from -60° to 10 °C, quadratic 10° 140 °C. Moreover, an ultrahigh sensitivity up -5.22 nm/°C 120 (i.e., -4.01 80 °C) is two...

We demonstrate a high-sensitivity gas pressure sensor by use of an in-fiber Fabry-Pérot interferometer (FPI) based on hollow-core photonic bandgap fiber (HC-PBF) with side-opened channel. The FPI was constructed splicing thin piece HC-PBF between two stander single-mode fibers. Then, channel drilled through the hollow core femtosecond laser. Such greatly enhanced sensitivity up to 4.24 nm/MPa, which is orders magnitude higher than that enclosed cavity. In addition, effects cavity length...

Abstract Hyperbolic metasurfaces with unique dispersion properties can manipulate light–matter interactions according to the demands. However, due their inherent physical properties, topological transitions (flat bands) exist only in orthogonal directions, which greatly limit application. Here, we unveil rich engineering and hyperbolic metasurfaces. Based on effective medium theory, rotation matrix is introduced into relation explain distorted energy band diagrams, iso-frequency contours...

We reported a gas pressure sensor based on CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -laser-induced long-period fiber grating (LPFG) in an air-core photonic bandgap (PBF). The LPFG was inscribed PBF by the use of improved laser system with ultraprecision 2-D scanning technique, which induced periodic collapses air holes along axis PBF. Such could be used to develop promising sensitivity -137 pm/MPa. Moreover, simplified model...

In this paper, we propose an approach to improve the sensitivity of optical fiber surface plasmon resonance (SPR) sensor with a pure higher-order mode excited by designed selective coupler (MSC). We calculate proportion power in cladding. Compared LP01 mode, LP11 (LP21 mode) cladding theoretically improves 100% (150%). To generate relatively or LP21 (MSC, 430–580 nm) is designed. The coupling efficiency LP01–LP11 over 80%, and that LP01–LP21 50%. simulation results show increases...

Diffuse correlation spectroscopy (DCS) is a noninvasive technique that derives blood flow information from measurements of the temporal intensity fluctuations multiply scattered light. Blood index (BFI) and especially its variation was demonstrated to be approximately proportional absolute flow. We investigated assessed utility long short-term memory (LSTM) architecture for quantification BFI in DCS. Phantom vivo experiments were established measure normalized autocorrelation function data....

Objective: Small molecules in snow chrysanthemum such as flavonoids, phenolic compounds and amino acids have been extensively investigated. No study to date has focused on water-soluble oligosaccharides. The objective of this is identification determination oligosaccharides chrysanthemum. Methods: were identified by high performance thin layer chromatography (HPTLC), liquid chromatography-mass spectrometry (LC-MS) combined MS library methylation analysis for the first time. Subsequently...

Various kinds of metasurfaces have been proposed because they can be tailored to achieve the desired modulations on electromagnetic wave that do not occur in nature. Compared conventional metamaterials, coding integrated with information science theory possess numerous distinctive advantages - simple design, time-saving and compatibility digital devices. Here we propose terahertz multifunctional anisotropic reflective a metal-insulator-metal cavity structure whose top constructional layer...