Multimode Sensor Research Articles

Product Design Method Based on Data Fusion and Transmission Based on Multimode Sensor

With the progress of society and the improvement of economic level, the traditional manufacturing industry is gradually transformed and upgraded in the changing times. In addition to the need for innovation in production technology, product design also plays a vital role in the sustainable development of the entire industry. However, the existing design methods have been unable to meet the high-quality requirements of consumers for material life. Therefore, this paper integrates multimodal sensor data fusion and transmission into product design. The multimodal sensor data fusion and transmission technology is developed on the basis of the human organs’ ability to comprehensively judge the environmental information. This paper gives a brief overview of product design methods on the basis of this theory. Among them, the generation, development, classification, attribute level, and emotional level of products of product design methods are studied. And through the research on multimodal data fusion algorithm, the design method based on multimodal sensor data fusion and transmission technology is designed and practiced, and compared with the traditional QFD technology design method. The experimental results show that the design method proposed in this paper has the highest market demand adaptability of 86.37%, which proves its effectiveness. Popularizing this technology and method in the current stage of manufacturing industry product design can effectively improve the quality and efficiency of the design process. This has practical significance for enhancing the core competitiveness of products in the market.

Self-powered and flexible piezo-sensors based on conductivity-controlled GaN nanowire-arrays for mimicking rapid- and slow-adapting mechanoreceptors

Human skin contains slowly adaptive (SA) and rapidly adaptive (RA) mechanoreceptors, which respond differently to external stimuli. Based on human tactile perception principles, the fabrication of a self-powered electronic skin (e-skin) that simultaneously mimics SA- and RA-mechanoreceptors is a prime need for robots and artificial prosthetics to interact with the surrounding environment. However, the complex process of merging multimode sensors to mimic SA- and RA-mechanoreceptors hinders their utilization in e-skins. We proposed SA- and RA-mechanoreceptors based on n-type and semi-insulating GaN nanowire arrays. The SA- and RA-mechanoreceptors demonstrated distinguished features such as grasping of objects and detection of their surface textures. Based on piezoelectric sensing principles, the proposed e-skin can simultaneously mimic static and dynamic pressure signals. Mechanoreceptors further detected several stimuli of various pressures with low and high frequencies. The response and reset times showed by SA-mechanoreceptors were 11 and 18 ms under 1-Hz frequency, which are rapid enough for practical e-skin applications.

Studies on characterization and enhanced magnetic field sensing performance of Bi1-xKxMn1-yCoyO3 nanopowders as a fiber optic clad modified region

Optical fiber combined with the pristine BiMnO3 (BMO), and K, Co co-doped BiMnO3 provides a good magnetic field sensing character. The different concentrations (5%, 10%, and 15%) of K and Co co-doped BiMnO3 (Bi1-xKxMn1-yCoyO3) nanopowders coated on the clad modified optical fiber. The Evanescent-based multimode sensor coated with a sensor element is established to detect a different range (17.2 mT to 190.6 mT) of applied magnetic fields at room temperature. The 5% of co-doped BiMnO3 has good sensitivity at 17.2 mT (∼14.3%) and 190.6 mT (∼78.3%) at 693 nm. The 5% co-doped BMO is calculated as an optical band gap of 0.82 eV, and an enhanced dielectric constant. And, 10% of co-doped BMO nanoparticles has the better magnetic field sensing characterization with LSPR and magnetic-optic effect at 693 and 772 nm.

Fluorescent markable multi-mode pressure sensors achieved by sandwich-structured electrospun P(VDF-HFP) nanocomposite films

The development of multi-functional piezoelectric polymer film is of great significance to many application fields, such as those involving wearable functional devices, flexible sensors, and actuators. In this study, multilayer P(VDF-HFP) nanocomposite films were prepared using electrospinning technology with the MWCNTs-COOH and Eu complexes as fillers to achieve a fluorescent labeled multimode pressure sensor. The sandwich-structured devices were prepared using both electrospun polyurethane (PU) nanofiber films and P(VDF-HFP) composite nanofiber films, where the P(VDF-HFP) composite nanofiber film was used as the core electroactive layer and the PU nanofiber film was used for the skin layers. The resulting sandwich-structured devices showed high sensitivity at ultra-low-pressure (<1 kPa), high piezoelectric output (2.1V), fluorescence functionality, excellent flexibility, and good thermal properties. Our results suggest that sandwich-structured devices based on fluorescent labeled electroactive P(VDF-HFP) composite nanofiber films have great potential for application in the fields of multi-functional flexible sensors and intelligent wearables. • Fluorescent markable multi-mode flexible pressure sensors were fabricated. • Synergistic effect of MWCNTs-COOH and Eu complexes greatly improves the piezoelectric outputs. • The sensors with high electric outputs exhibit high pressure sensitivity at ultra-low-pressure. • The nanocomposites can be applied as multifunctional flexible sensors and intelligent wearables.

Numerical analysis of the broadband interferometric sensor in the planar gradient-step index configuration

In the paper the model of an optical sensor based on a two-mode interference in a planar gradient-step index configuration is presented. The analyzed structure consists of a single-mode gradient index waveguide, made by Ag+-Na+ ion exchange, which is partially covered by a step-index SU-8 polymer layer. This step and gradient index structure forms a two-mode waveguide which is excited by a broadband light source from a selected spectral range. The refractive index variation of measured external surrounding affects the modal properties of multimode waveguide and the spectral field distribution at the output of the structure. Full Text: PDF ReferencesM. Błahut, "Numerical analysis of planar multimode optical sensor with active nanolayer", Opt. Appl. 50, 377 (2020). CrossRef M. Nordstrom et al J. Light. Technol. 25, 1284 (2007). CrossRef K. Gut, "Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides", Nanomaterials, 9, 729 (2019). CrossRef M. Błahut, "Numerical characteristics of the polarimetric interferometer made by K+-Na+ ion exchange", Opt. Appl. 27, 3 (1998). CrossRef https://www.filmetrics.com/refractive-index-database/BK7/Float-Glass DirectLink M. Błahut, "Model of the broadband interferometric optical biosensor in a planar configuration", Phot. Lett. Pol. 12, 28 (2020). CrossRef K. Gut, "Broad-band difference interferometer as a refractive index sensor", Opt. Express, 25, 31111 (2017). CrossRef

Dual-channel step multimode fiber SPR sensor based on sawtooth structure

The fiber SPR sensor with a single sensing channel can not detect multiple analytes at the same time and introduce the reference channel to eliminate nonspecific interference. Hereby we proposed a sawtooth dual-channel fiber SPR sensor based on WDM technology. By CO2 laser, multiple V-shaped grooves are processed on the step multimode fiber to form a sawtooth structure. The first stage of the sensor was fabricated by coating gold film on the sawtooth area, and the second stage was fabricated by coating gold film on the cladding area 2 cm behind the sawtooth area. The sensitivity and dynamic range of the two channels are 3114.86 nm/RIU and 1584.23 nm/RIU, 719.93 nm-854.2 nm, and 584.24 nm-667.62 nm, respectively. The proposed fiber SPR sensor employs the sawtooth structure to adjust the SPR resonance wavelength, so as to realize dual-channel sensing, which is of significance in the fields of simultaneous detection of multiple analytes and temperature compensation of reference channels.

Transfer learning and generalization of a neural-network-based multimode fiber position and imaging sensor under thermal perturbations

Fiber specklegrams created through multimode fibers have been utilized in a wide variety of imaging and sensing applications. In a practical environment it is useful to have a system that, after an initial calibration, produces reconstructed images and tracks the current state of relevant physical quantities such as the position or shape of the fiber. Neural networks provide the ability to extract and generalize the information contained in the specklegrams in order to produce accurate predictions even when experimental conditions are altered from their calibration state. Using a single-layer fully-connected network, we demonstrate the capability to perform robust image reconstruction under discrete position and temperature perturbations, as well as to classify the fiber position for different reconstructed images and thermal perturbations. On a test set with the same thermal state and bend configuration as for the training data, the network achieves near-perfect reconstruction and classification accuracy. Further, our neural network can generalize its position classification and image reconstruction capabilities across a 30 °C temperature perturbation with a high degree of accuracy, providing measurements that are robust to these variations, as well as calibrations that are stable and effective for several days. Moreover, using a low-temperature training set to initialize network weights, transfer learning is demonstrated by re-calibrating on a small set of data and shown to significantly improve robustness and performance of the imaging system on a high-temperature perturbation test set.

Cognitive sensor systems for NDE 4.0: Technology, AI embedding, validation and qualification

AbstractCognitive sensor systems (CSS) determine the future of inspection and monitoring systems for the nondestructive evaluation (NDE) of material states and their properties and key enabler of NDE 4.0 activities. CSS generate a complete NDE 4.0 data and information ecosystem, i. e. they are part of the materials data space and they are integrated in the concepts of Industry 4.0 (I4.0). Thus, they are elements of the Industrial Internet of Things (IIoT) and of the required interfaces. Applied Artificial Intelligence (AI) is a key element for the development of cognitive NDE 4.0 sensor systems. On the one side, AI can be embedded in the sensor’s microelectronics (e. g. neuromorphic hardware architectures) and on the other side, applied AI is essential for software modules in order to produce end-user-information by fusing multi-mode sensor data and measurements. Besides of applied AI, trusted AI also plays an important role in CSS, as it is able to provide reliable and trustworthy data evaluation decisions for the end user. For this recently rapidly growing demand of performant and reliable CSS, specific requirements have to be fulfilled for validation and qualification of their correct function. The concept for quality assurance of NDE 4.0 sensor and inspection systems has to cover all of the functional sub-systems, i. e. data acquisition, data processing, data evaluation and data transfer, etc. Approaches to these objectives are presented in this paper after giving an overview on the most important elements of CSS for NDE 4.0 applications. Reliable and safe microelectronics is a further issue in the qualification process for CSS.

Wearable multimode sensor with a seamless integrated structure for recognition of different joint motion states with the assistance of a deep learning algorithm

Accurate motion feature extraction and recognition provide critical information for many scientific problems. Herein, a new paradigm for a wearable seamless multimode sensor with the ability to decouple pressure and strain stimuli and recognize the different joint motion states is reported. This wearable sensor is integrated into a unique seamless structure consisting of two main parts (a resistive component and a capacitive component) to decouple the different stimuli by an independent resistance-capacitance sensing mechanism. The sensor exhibits both high strain sensitivity (GF = 7.62, 0–140% strain) under the resistance mechanism and high linear pressure sensitivity (S = 3.4 kPa−1, 0–14 kPa) under the capacitive mechanism. The sensor can differentiate the motion characteristics of the positions and states of different joints with precise recognition (97.13%) with the assistance of machine learning algorithms. The unique integrated seamless structure is achieved by developing a layer-by-layer casting process that is suitable for large-scale manufacturing. The proposed wearable seamless multimode sensor and the convenient process are expected to contribute significantly to developing essential components in various emerging research fields, including soft robotics, electronic skin, health care, and innovative sports systems applications.

Low-doped LaVO4:Eu3+ phosphor for multimode optical thermal sensing.

In the last decade much attention has been paid to the development of novel approaches in luminescence thermometry, which could allow contactless and noninvasive temperature sensing when traditional thermometers are useless. Typically, an optical thermometer exploits a distinct luminescence parameter to define temperature. However, the use of multimode sensors can significantly broaden the working range and improve the reliability of the temperature measurements. In this work, a Eu3+-doped LaVO4 sample was successfully utilized as a thermal sensor within a wide temperature range of 98-723 K based on monitoring various temperature-sensitive luminescence features. Different thermal sensing strategies were assessed and compared in terms of thermal sensitivity and temperature resolution. The best thermometric performances of the Eu3+-doped LaVO4 sensor reached an Sr = 1.49% K-1 and a ΔT = 0.6 K at room temperature. All the studies performed showed that the LaVO4:Eu3+ phosphor is a prospective multimode optical thermometer.

Optical Waveguide Sensors for Measuring Human Temperature and Humidity with Gel Polymer Electrolytes.

In this work, multimodal responsive optical waveguide sensors using a stable cross-linking gel polymer electrolyte are successfully designed and fabricated by bottom metal-printing technology. Temperature and humidity sensing characterization based on the polymer electrolyte is simulated and analyzed. The multimodal responsive properties of the photonic chip are defined based on the analysis of ion relaxation dynamics: optical phase variable to monitor temperature and optical attenuation variable to detect humidity. In the supervising temperature (36.0-38.0 °C) and relative humidity (45-65%) range, the temperature and humidity sensitivities of the device are measured as 0.5π rad/°C and 1.14 dB/% RH, respectively. The fast-response time for both temperature and humidity of the multifunctional sensor can be obtained as 4.21 ms and 1.32 s, respectively. These findings provide a feasible scheme for the design and application of temperature and humidity sensors in potential medical treatment. From gel polymer electrolytes to multimode monitoring applications, the application exploration of high stability and ultrafast response multimode waveguide sensors is gradually being carried out. This study has great significance for the comprehensive monitoring of sophisticated human physical signs by multimodal responsive waveguide sensors.

Distribution and function of TRP ion channels in stem cells

<p indent=0mm>Transient receptor potential (TRP) ion channels are nonselective, cationic permeable proteins located on the plasma membrane. They serve as multimode cellular sensors for the perception of physical or chemical stimuli, such as changes in temperature and osmotic pressure, and the perception of pungent and irritant chemicals. Increasing studies showed that these ion channels are not only involved in sensory function but also expressed in different stem cells and involved in regulating their biological characteristics. These studies indicated the potential roles of TRP ion channels in stem cells. This review summarizes the current studies and prospects of the distribution and function of TRP ion channels in stem cells.

Fiber-optic multimode interferometric curvature sensor based on small-inner-diameter hollow core fiber

A highly sensitive fiber-optic curvature sensor based on single mode fiber (SMF) and hollow core fiber (HCF) in an SMF–HCF–SMF multimode interferometric (MMI) structure is proposed. The sensor can be simply manufactured by fusing a short section of small-inner-diameter HCF between two SMFs. As the inner diameter of the HCF is smaller than the core diameters of the SMFs, multiple guiding modes can be excited directly in the sidewall of the HCF without any additional structures. Curvature can then be measured by monitoring the transmission spectrum shift caused by the bending-sensitive MMI effect. Experiments show that a high sensitivity of ∼19.88 nm/m−1 can be achieved in a curvature range of 0.48–1.52 m−1. The sensor also has low-temperature sensitivity.

Significantly enhanced coupling effect and gap plasmon resonance in a MIM-cavity based sensing structure

Herein, we design a high sensitivity with a multi-mode plasmonic sensor based on the square ring-shaped resonators containing silver nanorods together with a metal–insulator-metal bus waveguide. The finite element method can analyze the structure's transmittance properties and electromagnetic field distributions in detail. Results show that the coupling effect between the bus waveguide and the side-coupled resonator can enhance by generating gap plasmon resonance among the silver nanorods, increasing the cavity plasmon mode in the resonator. The suggested structure obtained a relatively high sensitivity and acceptable figure of merit and quality factor of about 2473 nm/RIU (refractive index unit), 34.18 1/RIU, and 56.35, respectively. Thus, the plasmonic sensor is ideal for lab-on-chip in gas and biochemical analysis and can significantly enhance the sensitivity by 177% compared to the regular one. Furthermore, the designed structure can apply in nanophotonic devices, and the range of the detected refractive index is suitable for gases and fluids (e.g., gas, isopropanol, optical oil, and glucose solution).

Exposed-core fiber multimode interference sensor

In this manuscript, we report on, to the best of our knowledge, the first experimental realization of a multimode interference device based on self-image phenomenon accomplished by using a microstructured-cladding exposed-core fiber set in a singlemode-multimode-singlemode (SMS) configuration. Its application as a refractive index sensor is also demonstrated. The specialty multimode fiber studied herein exhibits a holey microstructure that surrounds and defines the fiber core. The latter, in turn, interfaces the external fiber environment thanks to lateral access along the entire fiber length. To explore the device's sensing capabilities, numerical simulations have been carried out, and the system sensitivity and spectral characteristics were evaluated. The experimental results demonstrate a refractive index sensitivity of 890 nm/RIU in the refractive index range from 1.41 to 1.43 with a detection limit of 2.7 × 10−3 RIU. This novel SMS configuration has the potential to extend the capabilities of current multimode interference-based sensors by providing an additional path to the realization of refractive index monitoring in liquid samples.

The Recent Progress on Halide Perovskite-Based Self-Powered Sensors Enabled by Piezoelectric and Triboelectric Effects

Sensors have recently gathered significant attention owing to the rapid growth of the Internet of Things (IoT) technology for the real-time monitoring of surroundings and human activities. Particularly, recently discovered nanogenerator-based self-powered sensors are potential candidates to overcome the existing problems of the conventional sensors, including regular monitoring, lifetime of a power unit, and portability. Halide perovskites (HPs), with an excellent photoactive nature, dielectric, piezoelectric, ferroelectric, and pyroelectric properties, have been potential candidates for obtaining flexible and self-powered sensors including light, pressure, and temperature. Additionally, the photo-stimulated dielectric, piezoelectric, and triboelectric properties of HPs make them efficient entrants for developing bimodal and multimode sensors to sense multi-physical signals individually or simultaneously. Therefore, we provide an update on the recent progress in self-powered sensors based on pyroelectric, piezoelectric, and triboelectric effects of HP materials. First, the detailed working mechanism of HP-based piezoelectric, triboelectric, and pyroelectric nanogenerators—operated as self-powered sensors—is presented. Additionally, the effect of light on piezoelectric and triboelectric effects of HPs, which is indispensable in multimode sensor application, is also systematically discussed. Furthermore, the recent advances in nanogenerator-based self-powered bimodal sensors comprising HPs as light-active materials are summarized. Finally, the perspectives and continuing challenges of HP-based self-powered sensors are presented with some opportunities for future development in self-powered multimode sensors.

An ASIC-Based Miniaturized System for Online Multi-Measurand Monitoring of Lithium-Ion Batteries

To better asses the ageing and to reduce the hazards involved in the use of Lithium-Ion Batteries, multi-measurand monitoring units and strategies are urged. In this paper, a Cell Management Unit, based on the SENSIPLUS chip, a recently introduced multichannel, multi-mode sensor interface, is described. SENSIPLUS is a single System on a Chip combined with a reduced number of external components, resulting in a highly miniaturized device, built on 20 × 8 mm2 printed circuit board. Thanks to SENSIPLUS’ versatility, the proposed system is capable of performing direct measurements (EIS, cell voltage) on the cell it is applied to, and reading different kinds of sensors. The SENSIPLUS versatile digital communication interface, combined with a digital isolator, enable connection of several devices to a single bus for parallel monitoring a large number of cells connected in series. Experiments performed by connecting the proposed system to a commercial Lithium-Ion Battery and to capacitive and resistive sensors are described. In particular, the capability of measuring the cell internal impedance with a resolution of 120 μΩ is demonstrated.

Numerical and experimental study of a multimode optical fiber sensor based on Fresnel reflection at the fiber tip for refractive index measurement

This paper presents the numerical and experimental study of a multimode optical fiber (MMF) sensor based on Fresnel reflection at the fiber tip. Considering different modal power distributions (uniform mode distribution, gaussian and equilibrium mode distribution), the effective fraction of the incident light reflected at the interface between the end of the fiber and the surrounding medium is first calculated numerically with a ray model. Even when considering modal power distribution and non-normal incidence influence, simplifying assumptions such as normal incidence hypothesis can be made to facilitate experimental data exploitation, with a maximum error on the deduced medium refractive index of the 10-4 order. A statistical analysis of noise is then made, to study the influence of a random noise between 0.1% and 5% noise level: results show that the approximation error made by using normal incidence formula for a Fresnel sensor based on a MMF is significantly smaller than the repeatability error. These assumptions are then verified experimentally with two experimental setups by measuring the refractive index at 1550 nm of reference solutions (distilled water-isopropanol and distilled water-sodium chloride mixtures) with a Fresnel based on a multimode fiber, and a Fresnel based on single-mode fiber for comparison. Good agreement is found with refractive index values from the literature with a maximum relative difference of only 0.1%, and the maximum experimental uncertainties in this work is 1.1×10-4. Differences between refractive index measured with a Fresnel based on single-mode and multimode fiber are found to be in accordance with values from the statistical study.

Modified fiber optic sensor for highly precise identification of mercuric ion (Hg2+) concentrations in aqueous solution

A fiber optic sensor for monitoring mercuric (Hg2+) ions in the aqueous sample have been developed based on modified cladding. To fabricate a D-shaped sensing zone onto the multimode optical fiber lengthwise polishing was utilized using a mechanical end and edge polishing system. The produced sensing region has dimensions of 10 mm × 125 μm × 62 μm (l × w × h). A 2 μm thin layer of Al2O3 nanoparticles sensitized with 4-(2-pyridylazo)-resorcinol was deposited onto the sensing element of multimode fiber optic sensor to make it sensitive and selective for Hg2+ ions. The analytical results demonstrate that the sensing device has a linear response for Hg2+ ions concentration over a range from 4 to 16 ppm along with a 4 ppm limit of detection in an aqueous sample at room temperature. The selectivity of the sensor is examined for the recognition of Hg2+ ions in presence of other cations such as zinc and/or lead ions up to 16 ppm in an aqueous solution. The main merits of this fabricated sensor are easy and safe installation, rapid response, enhanced linear response range, and better selectivity towards Hg2+ ions.

Fiber microsphere SPR sensor and its detection of low concentration Hg2+

We propose and demonstrate a fibre surface plasmon resonance (SPR) sensor based on a microsphere structure. By employing the microsphere fibre, the cladding mode of the fibre is excited and provides an evanescent field for the SPR sensing structure. The relationship between the diameter of the microsphere, the diameter of the fibre core, the types of fibres, and the sensing performance of the sensing probe are studied experimentally. Based on the experimental results, optimum parameters are obtained that result in the sensitivity of refractive index testing reaching 3570.46 nm/RIU, much higher than that of other common multimode SPR sensors. Furthermore, to detect Hg2+ in solution, we chemically modified the sensing film of the sensor with 1, 6-hexanedithiol. The resultant sensor can detect a 5 pM Hg2+ solution target, which demonstrates the sensor’s low chemical detection limit. The proposed fibre microsphere SPR sensor has a simple and stable structure which greatly increases evanescent field leakage. When the sensing film is functionalised accordingly, the sensor can be used in food security, medicine, biochemistry, etc.