JournalTOCs

Photonic Sensors
Journal Prestige (SJR): 0.432

Citation Impact (citeScore): 2
Number of Followers: 7

This is an Open Access Journal

Open Access journal
ISSN (Print) 1674-9251 - ISSN (Online) 2190-7439
Published by SpringerOpen

[229 journals]

Au-Nanocoated Twisted-SMF for Multiparameter Sensor
- Abstract: In this paper, we experimentally demonstrated the application of the Au-nanocoated twisted single-mode fiber (Au-TSMF) structure for the response of the multiparameter. Firstly, we fabricated an Au-TSMF, which achieved high sensitivity to refractive index (RI) and torsion. Additionally, based on the theory of polarization interference, we amplified its polarization sensitivity and induced the phase factor caused by polarization as a wavelength shift. Ultimately, we achieved the response of the Au-TSMF structure to the multiparameter, which had the sensitivity of −0.436 dB/(deg/m) for clockwise torsion, −0.156 dB/(deg/m) for anticlockwise torsion, 0.391 5 nm/rad for the left-handed circularly polarized state, −0.926 nm/rad for the right-handed circularly polarized state, and −692.9 dB/RIU for RI. Due to the advantages of the all-fiber integrated system, this work holds great potential for facilitating fiber optic integrated devices for optical fiber biosensors and biomedical diagnostic applications.
  PubDate: 2025-03-17
Remarks of Optical Fibers and Devices for Microfluidic Sensing:
Preparation and Processing
- Abstract: With the gradual maturity of the microfluidic technology, the integration of the microfluidic chip technology and optofluidic methods in microstructured optical fibers (MOFs) has gradually formed a highly attractive new research direction. In this paper, we summarize our recent work focusing on the microfluidic sensing technology based on microhole fibers. The design and fabrication of such microfluidic fibers, device processing and fabrication techniques based on microfluidic fibers, and surface modification and coating methods for fibers are systematically introduced. Finally, several typical cases combining the optical fiber and microfluidic substance detection are presented.
  PubDate: 2025-02-17
Three-Dimensional Reconstruction Method Based on Infrared Deflectometry
- Abstract: Deflectometry is a non-contact and rapid detection method with high sensitivity, which can be utilized in the areas of three-dimensional (3D) reconstruction, surface quality detection, and defect location. It has important applications in the automotive industry, optical parts manufacturing, and other fields. Classical deflectometry methods require the integration of slope data to reconstruct the absolute surface shape. However, the integration procedure is error-prone due to the accumulation of random errors into large shape deviations, resulting in inaccurate measurement results. In this paper, we extract the position of the centerline of the bright fringe from the stripe image and find the center of the fringe line point by point. Using the principle of triangulation, the 3D data for the object’s shaped surface can be obtained. In addition, infrared light enhances specular reflection, resulting in better deflectometry performance than that of visible light. Experiments show that the proposed method is sensitive to the changes in height and can roughly restore the surface topography of the object without calibration.
  PubDate: 2025-02-11
Artificial Neural Networks as Digital Twins for Whispering Gallery Mode
Optical Sensors in Robotics Applications
- Abstract: This paper investigates the use of artificial neural networks (ANNs) as a viable digital twin or alternative to the typical whispering gallery mode (WGM) optical sensors in engineering systems, especially in dynamic environments like robotics. Because of its fragility and limited endurance, the WGM sensor which is based on micro-optical resonators is inappropriate in these kinds of situations. In order to address these issues, the paper suggests an ANN that is specifically designed for the system and makes use of the WGM sensor’s high-quality factor (Q-factor). By extending the applicability and endurance to dynamic contexts and reducing fragility problems, the ANN seeks to give high-resolution measurement. In order to minimize post-processing requirements and maintain system robustness, the study goal is for the ANN to function as a representative predictor of the WGM sensor output. The GUCnoid 1.0 humanoid robot is used in the paper as an example to show how the WGM optical sensors may improve humanoid robot performance for a variety of applications. The results of the experiments demonstrate that the sensitivity, precision, and resolution of ANN outputs and actual WGM shifts are equivalent. As a consequence, current obstacles to the widespread use of high-precision sensing in the robotics industry are removed, and the potential of ANNs as virtual substitutes or the digital twin for genuine WGM sensors in robotics systems is validated. So, this paper can be very beneficial not only to the sensing technologies that are used in robotics, which are subjected to the dynamic environments, but also to the industrial automation and human-machine interface.
  PubDate: 2025-02-07
Synthetic Receptors Decorated on Nanoparticles for Selective and Sensitive
Glyphosate Detection
- Abstract: Herein, an innovative glyphosate imprinted poly(hydroxyethyl methacrylate-N-methacroyl-(L)-phenylalanine methyl ester nanoparticles (MIP@NPs) based plasmonic nanosensor featured with high sensitivity and selectivity was constructed by using the molecular imprinting technique and used for real-time glyphosate detection. The characterization of nanoparticles was performed by the nano Zetasizer and scanning electron microscopy (SEM), while nanosensors were characterized by the Fourier transform infrared-attenuated total reflection (FTIR-ATR) and contact angle measurement. Control experiments were conducted to evaluate the imprinting efficiency on the signal response using a non-imprinted surface plasmon resonance (NIP SPR) nanosensor prepared without adding glyphosate pesticide into the polymerization mixture. The MIP@NPs integrated molecularly imprinted surface plasmon resonance (MIP SPR) nanosensor having synthetic molecular recognition elements yielded a novel biosensing platform for label-free detection and real-time monitoring of glyphosate pesticide. The MIP SPR nanosensor detected the target glyphosate molecule 4.950 times more selectively than the competitor molecule malathion while 3.918 times more selectively than the competitor molecule malaoxon. In addition, the imprinting efficiency factor was found to be 6.76, indicating that the molecular imprinting process was successful. In addition, the imprinting factor was found to be 6.76. Kinetic studies and adsorption characteristics of glycosate adsorption were carried out to assess adsorption dynamics. The linear concentration range for glyphosate detection was 0.001 ppm–10.000 ppm of pesticide, and the detection limit was found to be 0.120 ppb. Studies on the repeatability of the MIP SPR nanosensor revealed that even after five cycles, the signal response for glyphosate detection did not change significantly with relative standard deviation, RSD
  PubDate: 2025-01-30
FBG-Based UV-Curing Kinetics Analysis by Exothermic Behavior
- Abstract: Since photo-induced polymerization of the ultra-violet (UV)-curing adhesive from a fluid state to a solid state is an exothermic process, the UV curing exothermic behavior can be regarded as a potential evaluation methodology to analyze UV-curing kinetics. Herein, a fiber Bragg grating (FBG)-based UV curing exothermic behavior monitoring is proposed to evaluate the UV-curing dynamic process and analyze a series of thermal and mechanical properties changes during curing. The exothermic behavior of the UV curing adhesive during curing and the feasibility of FBG-based curing kinetic analysis scheme are verified experimentally, full cycle cure monitoring of the UV curing adhesive can be realized by this FBG-based curing kinetic analysis scheme, and the UV-curing kinetics of four different types of the UV curing adhesive are corresponding to different exothermic behaviors. Compared with curing process evaluation based on refractive index variation, this FBG-based exothermic behavior monitoring has the ability to extract more details of the curing process, and some curing stages with negligible refractive index changes also can be distinguished. By using this proposed scheme, the UV-curing dynamic process and multiple characteristic parameters, such as curing time, time constant, transient temperature rise, and residual stress, can be evaluated, which may contribute to evaluating and analyzing UV-curing kinetics more comprehensively.
  PubDate: 2025-01-22
Two-Dimensional Reconstructed Image of a Subsurface Structure Using
Continuous Scanned Photothermal Imaging
- Abstract: This study presents the two-dimensional (2D) image of a subsurface structure reconstructed using an imaging method based on the photothermal effect. The photothermal imaging method is based on the deflection method using two lasers: pump and probe lasers. A continuous scanning technique is proposed for 2D (x- and y-directions) surface scanning. The continuous scanning method is compared with the conventional point-by-point scanning technique, and a low-pass fast Fourier transform filter and a Marr-Hildreth detector are found to produce significant results. The photothermal imaging method with continuous 2D surface scanning is performed on three copper-resin double-layer samples with different subsurface structures. The subsurface structures of the copper-resin double-layer samples comprise a square block of 5×5 mm2 area and blocks shaped as the alphabet letters “T” and “F”. The letters are 3 mm wide and 10×13 mm2 in area. All three shapes are 1 mm thick and located at a depth of 0.5 mm from the surface of the copper block. The reconstructed photothermal images show an absolute error within 0.122 mm compared with the actual subsurface structure, equivalent to a 2.3% relative error.
  PubDate: 2025-01-21
Optical Fiber Hydrogen Sensor Based on π-Phase-Shifted Grating and
Sputtered Pd/Hf Composite Film
- Abstract: A novel optical fiber hydrogen sensor based on the π-phase-shifted grating and partial coated Pd/Hf composite film is proposed and experimentally demonstrated in this paper. The hydrogen sensitive Pd/Hf film with the length of 4 mm is successfully deposited in the π-phase-shifted grating region by the magnetron sputtering process and rotating fixture technology. Since the hydrogen sensitivity between the notch and flank wavelengths of the π-phase-shifted grating is different due to the partial coating only on the π-phase-shifted grating region, the relative shift between the notch and flank wavelengths is employed to characterize the hydrogen concentration in this paper. The hydrogen calibration results show that the sensor shows the good response and repeatability. At the temperature of 20 °C and the hydrogen concentration of 2%, the wavelength distance shifts of 200 nm and 500 nm Pd/Hf coatings are 12.6 pm and 33.5 pm, respectively.
  PubDate: 2025-01-21
Humidity Sensor Based on a Hollow Core Fiber Anti-Resonant Reflection
Optical Waveguide
- Abstract: In this paper, a graphene oxide (GO) composite film-coated humidity sensor is proposed based on the hollow core fiber (HCF). A segment of the HCF is spliced between two segments of the single-mode fiber (SMF). The relative humidity (RH) sensing characteristics of the sensor are experimentally investigated by observing the intensity shift of resonant dips in the transmission spectrum, which shows the GO composite film-coated HCF has the good stability in the measurement of humidity. The maximum humidity sensitivity of 0.12 dB/%RH is obtained in the RH range of 30%–78%. The proposed sensor has the advantages of the simple structure, easy fabrication, good stability, and high performance, which can be applied to marine climate detection, tunnel air humidity detection, agricultural testing, and other fields.
  PubDate: 2025-01-21
Enhancing Gas Diffusion in Antiresonant Hollow-Core Fiber Gas Sensors
Using Microchannels
- Abstract: In this paper, we analyze the performance of diffusion-based gas distribution in antiresonant hollow-core fiber-based gas absorption cells. Performed theoretical analysis was based on Fick’s second law using the OpenFOAM® software and finite volume method (FVM), followed by an experimental verification of the obtained simulations. The diffusion time was tested for a 1.25 m long fiber, with laser-micromachined microchannels. Full analysis of the correlation between the microchannel count, position, and separation on the rate at which the fiber-based gas cell was filled with the target gas was presented. Experimental results showed that with the proper microchannel configuration, the purely-diffusion-based gas exchange time in the 1.25 m fiber could be reduced from 6 h, down to 330 s. Obtained results correlated with the simulations, giving perspective for the development and implementation of novel miniaturized passively filled gas absorption cells for compact laser spectrometers.
  PubDate: 2025-01-04
Review of Optical Fiber Optofluidic Chemical Sensors and Biosensors
- Abstract: Optical fiber sensors have gained significant attention in recent years owing to their remarkable advantages of remote operation and rapid response. The integration of optical fiber sensing with the microfluidics technology has paved the way for the establishment of optical fiber optofluidic sensing. Optical fiber optofluidic systems possess the advantages of the low invasiveness, compact structure, excellent biocompatibility, and the ability to handle small analyte volumes, rendering them particularly suitable for serving as chemical sensors and biosensors. In this paper, we present an in-depth overview of optical fiber optofluidic chemical sensors and biosensors. Firstly, we provide a comprehensive summary of the types of optical fibers commonly employed in optofluidic chemical and biosensing, elucidating their distinct attributes and performance characteristics. Subsequently, we introduce and thoroughly analyze several representative sensing mechanisms employed in optical fiber optofluidic systems and main performance parameters. Furthermore, this review delves into the modification and functionalization of optical fibers. Additionally, we showcase typical biosensing and chemical sensing applications to demonstrate the practicality and versatility of optical fiber optofluidic sensing. Finally, the conclusion and outlook are given.
  PubDate: 2024-12-19
Polymer-Dispersed Liquid Crystal Gas Sensor for Acetone Detection Using
Correlated Laser Speckles
- Abstract: Acetone is a widely used volatile organic compound in various industries, and several gas sensors have been developed for its detection and real-time monitoring. This study reported a novel method for determining the acetone vapor concentration based on correlated laser speckles using polymer-dispersed liquid crystals (PDLCs). Here, PDLC films comprising a mixture of the thermotropic nematic liquid crystal (LC) and ultraviolet-curable polymers were fabricated using different LC mass ratios and ultraviolet curing conditions. The laser beam was transmitted through the PDLC film to generate scattered light and speckles. When the PDLC film was exposed to the acetone vapor, the acetone molecules diffused into the PDLC film and interacted with the LC molecules, modifying the orientation of the LC molecules and the equivalent refractive index of the LC droplets. This in turn decreased the correlation coefficient of the speckle images. The experimental results indicated that the PDLC gas sensor was selectively sensitive to different concentrations of the acetone vapor, ranging from 1 800 ppm to 3 200 ppm. In comparison with traditional LC gas sensors that use a polarizing microscope to detect the change in brightness of the modulated light field, the proposed method is simpler, less expensive, and more robust under external disturbances such as vibrations.
  PubDate: 2024-12-19
Electropolymerized Dopamine Film-Modified Optical Fiber LMR Biosensor for
Immunoassay
- Abstract: In producing high-performance optical biosensors, the selected coupling agent and its fixation mode play an essential role as one of the decisive conditions for antibody incubation. In this work, we designed optical fiber biosensors by electrochemical polymerization to enable low detection limit (LOD) immunoassay. Based on the optical fiber lossy mode resonance (OF-LMR) achieved by In2O3-SnO2-90/10 wt% (ITO), we have simultaneously implemented the electropolymerized dopamine (ePDA) film on the ITO-coated fiber via the electrochemical method, utilizing the excellent electrical conductivity of ITO. After that, the immunoglobulin G (IgG) antibody layer was immobilized on the entire sensing region with the assistance of the ePDA film. The results of immunoassay were analyzed by recording the shift of the LMR resonance wavelength to verify the sensor performance. The LOD was evaluated as the lowest concentration of human IgG detected by the OF-LMR sensor, which was confirmed to be 4.20 ng·mL−1. Furthermore, the sensor achieved selective detection for specific antigens and exhibited a good recovery capability in chicken serum samples. The developed scheme provides a feasible opportunity to enhance the intersection of electrochemistry and optics subjects and also offers a new promising solution to achieve the immunoassay.
  PubDate: 2024-11-29
Seven-Core Fiber Composite Structures-Based Mach-Zehnder Interferometer
for Bending and Temperature Measurement
- Abstract: In the paper, an optical fiber sensor based on a seven-core fiber composite structure is presented, which enables dual-parameter sensing of bending and temperature. The proposed structure is fabricated by combining the strongly-coupled seven-core fibers (SC-SCFs) and a weakly-coupled seven-core fiber (WC-SCF). The SC-SCF acts as a beam coupler and enhances the Mach-Zehnder interference, while the WC-SCF serves as the enhanced section of another Mach-Zehnder interference. Therefore, the spectrum response of the fiber structure mentioned above exhibits a superposition effect of two Mach-Zehnder interferometers (MZIs). Among them, two dips corresponding to different MZIs are used to measure bending and temperature. The experimental results show the bending sensitivity and temperature sensitivity of the two MZIs are −4.238 nm/m−1, −2.263 nm/m−1, 0.047 nm/°C, and 0.064 nm/°C, respectively. It proves that our sensor is very sensitive to bending. Through the dual-wavelength matrix method, the bending and temperature can be measured simultaneously. With the benefit of the composite structure, low cost, and ease of fabrication, the proposed sensor can be used in harsh environments.
  PubDate: 2024-11-12
Surface Functionalized Plasmonic Sensors for Uric Acid Detection With
Gold-Graphene Stacked Nanocomposites
- Abstract: This study presented a surface-functionalized sensor probe using 3-aminopropyltriethoxysilane (APTES) self-assembled monolayers on a Kretschmann-configured plasmonic platform. The probe featured stacked nanocomposites of gold (via sputtering) and graphene quantum dots (GQD, via spin-coating) for highly sensitive and accurate uric acid (UA) detection within the physiological ranges. Characterization encompassed the field emission scanning electron microscopy for detailed imaging, energy-dispersive X-ray spectroscopy for elemental analysis, and Fourier transform infrared spectroscopy for molecular identification. Surface functionalization increased sensor sensitivity by 60.64%, achieving 0.0221 °/(mg/dL) for the gold-GQD probe and 0.035 5 °/(mg/dL) for the gold-APTES-GQD probe, with linear correlation coefficients of 0.8249 and 0.8509, respectively. The highest sensitivity was 0.070 6 °/(mg/dL), with a linear correlation coefficient of 0.993 and a low limit of detection of 0.2 mg/dL. Furthermore, binding affinity increased dramatically, with the Langmuir constants of 14.29 µM−1 for the gold-GQD probe and 0.000 1 µM−1 for the gold-APTES-GQD probe, representing a 142 900-fold increase. The probe demonstrated notable reproducibility and repeatability with relative standard deviations of 0.166% and 0.013%, respectively, and exceptional temporal stability of 99.66%. These findings represented a transformative leap in plasmonic UA sensors, characterized by enhanced precision, reliability, sensitivity, and increased surface binding capacity, synergistically fostering unprecedented practicality.
  PubDate: 2024-11-12
Review on In-Situ Marine Monitoring Using Physical and Chemical Optical
Fiber Sensors
- Abstract: Optical fiber sensors (OFSs) have attracted more and more attention in the field of in-situ ocean observation because of their advantages of the small size, light weight, low cost, and intrinsic immunity to electromagnetic interference. Here, we comprehensively reviewed the development of various advanced physical and chemical OFSs for in-situ measurement of ocean key parameters, including temperature, salinity, pressure, acoustics, flow velocity and turbulence, potential of hydrogen (pH), heavy metal ions, nitrates, and gases. Moreover, the performances of different kinds of OFSs and their practical sea trial reports for in-situ measurement in the marine environment are provided. As we discussed, the field of OFS is rapidly evolving and is poised to make essential breakthroughs in marine monitoring, leading to better utility of marine resources.
  PubDate: 2024-10-25
Femto-Laser Processed Metasurface With Fano Response: Applications to a
High Performance Refractometric Sensor
- Abstract: The practical development of compact modern nanophotonic devices relies on the availability of fast and low-cost fabrication techniques applicable to a wide variety of materials and designs. We have engraved a split grating geometry on stainless steel using femtosecond laser processing. This structure serves as a template to fabricate efficient plasmonic sensors, where a thick gold layer is grown conformally on it. The scanning electron microscope (SEM) images confirm the generation of the split laser-induced periodic spatial structures. The optical reflectance of our sensors shows two dips corresponding to the excitation of surface plasmon resonances (SPRs) at two different wavelengths. Furthermore, the asymmetric shape of these spectral responses reveals a strong and narrow Fano resonance. Our computational electromagnetism models accurately reproduce the reflectivity of the fabricated structure. The spectral responses of both the simulated and fabricated structures are fitted to the Fano model that coherently combines the narrow SPRs with the broad continuum background caused by diffraction. The parameters extracted from the fitting, such as the resonance wavelengths and line widths, are used to evaluate the performance of our device as a refractometric sensor for liquids. The maximum sensitivity and figure of merit are 880 nm/RIU and 80 RIU−1, respectively. Besides the compact design of our sensing device, its performance exceeds the theoretical maximum sensitivity of a classical Kretschmann setup.
  PubDate: 2024-10-22
Ultrafast and Reproducible Fiber-Optic Hydrogen Sensor via a Tilted Fiber
Grating With Pd/WO3 Nanocoating
- Abstract: Hydrogen, a high-density and clean energy, has been widely used in various critical applications. However, the safety risk caused by hydrogen leakage during storage and transportation is still a non-negligible issue. Therefore, it is necessary to offer hydrogen sensors with fast response and high repeatability, and it will be perfect for achieving in situ monitoring over the lifecycle of hydrogen production and utilization. Here, we propose a compact optical fiber sensor with a short section of the tilted Bragg fiber grating (TFBG) inscribed in the fiber core and a palladium and tungsten trioxide (Pd/WO3) combined film of 40 nm thickness over the fiber surface. The TFBG excites tens of narrow cladding resonances, part of which possess refractive indexes matching that of the Pd/WO3 coating and providing the high sensitivity to the surrounding hydrogen concentration change. The sensor offers improved sensing characteristics, including the fast response time (less than 10 s), high repeatability (over tens of measurement), and excellent linear response (higher than 99.6%) over the 0% to 3% concentration range.
  PubDate: 2024-10-22
Experimental Study of Fiber-Optic Temperature Sensor Based on Dual FSIs
- Abstract: To improve the sensitivity measurement of temperature sensors, a fiber optic temperature sensor structure based on the harmonic Vernier effect with two parallel fiber Sagnac interferometers (FSIs) is designed, and theoretical analysis and experimental testing are conducted. The FSI consisting of two polarization maintaining fibers (PMFs) with lengths of 13.62 m and 15.05 m respectively is used to achieve the basic Vernier effect. Then by changing the length of one PMF to approximately i times that of the others, the FSI composed of two PMFs of 7.1 m and 15.05 m is used to achieve the first-order harmonic Vernier effect. Afterward, temperature sensing tests are conducted to observe the wavelength drift during temperature changes and ultimately achieve high sensitivity. The experimental results show that the temperature sensitivity of the sensor based on the first-order harmonic Vernier effect is −28.89 nm/°C, which is 17.09 times that of a single FSI structure (−1.69 nm/°C) and 1.84 times that of the sensitivity generated by the structure based on the basic Vernier effect (−15.69 nm/°C). The experimental results are consistent with the theoretical analysis. The structure proposed in this paper achieves drift measurement of 0.1 °C variation based on 1 °C drift, making the fiber optic temperature sensor applicable to related fields that require high precision temperature. The proposed temperature sensor has the simple structure, low production cost, high sensitivity, and broad application prospects.
  PubDate: 2024-09-26
Exploration of Biologically-Inspired Nanostructures: Review on the Sensing
Potential and Technological Integration of the Morpho Butterfly Wing
- Abstract: The surge in demand for cost-effective, lightweight, and rapidly responsive sensors has propelled research in various fields, and traditional sensors face limitations in performing up to the mark due to their intrinsic properties and a lack of innovative fabrication techniques. Consequently, over the last decade, a notable shift has been toward harnessing naturally existing nanostructures to develop efficient and versatile sensing devices. One such nanostructure in morpho butterfly wings has attracted attention because of its vibrant uniqueness and diverse sensing properties. This review will explore recent interdisciplinary research endeavors on the nanostructure, including chemical, vapor, and acoustic detection. Furthermore, its potential as an infrared sensor, considerations related to heat transfer properties, and a brief overview of various replication techniques and challenges encountered in reproducing the intricate nanostructure are discussed.
  PubDate: 2024-09-26

HOME > Browse the 73 Subjects covered by JournalTOCs
Subject	Total Journals