Open Access Article
All Fiber Mach–Zehnder Interferometer Based on Intracavity Micro-Waveguide for a Magnetic Field Sensor
Viewed by 474
Abstruse
A magnetic fluid (MF)-based magnetic field sensor with a filling-splicing cobweb structure is proposed. The sensor realizes Mach–Zehnder interference past an optical cobweb cascade structure consisting of single mode fiber (SMF), multimode fiber (MMF), and single-hole-dual-core fiber (SHDCF). The cadre in the cladding [...] Read more than.
A magnetic fluid (MF)-based magnetic field sensor with a filling-splicing cobweb structure is proposed. The sensor realizes Mach–Zehnder interference by an optical fiber cascade construction consisting of unmarried mode fiber (SMF), multimode fiber (MMF), and single-hole-dual-cadre fiber (SHDCF). The core in the cladding and the core in the air pigsty of SHDCF are used as the reference and sensing low-cal path, respectively, and the air hole of SHDCF is filled with magnetic fluid to realize magnetic field measurement based on magnetic controlled refractive index (RI) characteristics. The theoretical feasibility of the proposed sensing structure is verified by Rsoft simulation, the optimized length of SHDCF is adamant by optical fiber light transmission experiment, and the SHDCFs are well fused without collapse through the special parameter setting. The results prove that the sensitivity of the sensor is −116.ane pm/Gs nether a magnetic field of 0~200 Gs with a good long-term operation stability. The proposed sensor has the advantages of high stability, fast response, uncomplicated construction, and low price, which has development potential in the field of miniaturized magnetic field sensing. Full commodity
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Open Access Article
High-Precision Surface Scattering Measurement System and Doubt Analysis Applied in Laser Protective Materials Diagnostics
Viewed by 399
Abstract
The current measurement system of surface scattering rate applied in laser protective materials has the defects of depression accuracy, discontinuous diagnosis region and narrow infrared measuring waveband. In order to make upwardly for these shortcomings, a high-precision material-surface-scattering-rate measurement system based on a [...] Read more.
The electric current measurement organisation of surface handful rate practical in laser protective materials has the defects of low accuracy, discontinuous diagnosis region and narrow infrared measuring waveband. In gild to brand upwardly for these shortcomings, a high-precision textile-surface-scattering-rate measurement system based on a three-hole integrating sphere is proposed, which can realize the high-precision quantitative measurement on whatsoever region of blanket surface from near-infrared to far-infrared band. Firstly, a new quantitative relationship between the luminous flux received by detector and the surface scattering rate of coating is obtained by modifying the existing integrating sphere scattering model. Secondly, a high-precision scattering characteristic measurement system based on a three-hole integrating sphere is designed and achieved. The influence of the principal blueprint parameters of the integrating sphere on the expected measuring accuracy of the organisation is investigated past using a TracePro simulation. Accordingly, the optimal design parameters of the system are given. And so, the principal sources of the relative measurement incertitude for the handful rate are investigated experimentally, and 4 chief relative uncertainty factors are evaluated quantitatively. Finally, according to the error propagation theory, the total experimental relative measurement uncertainty of the organisation is obtained, which is ±2.22% and 26–56% higher than the current measuring accurateness. The new blanket-scattering-rate measurement system proposed in this newspaper can provide an effective experimental detection means for loftier-precision quantitative measurement and a performance evaluation for laser-protective-coating surface-scattering rate. Full article
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Open up Access Commodity
Terahertz Raman Measurements Using a Spatial Heterodyne Raman Spectrometer
Viewed by 509
Abstract
We propose a method of measuring the terahertz (THz) Raman spectra of a material. As Raman spectroscopy is a measurement of the relative frequency spectrum relative to the frequency of the excitation source, sometimes it is not necessary to apply an expensive THz [...] Read more.
Nosotros propose a method of measuring the terahertz (THz) Raman spectra of a material. As Raman spectroscopy is a measurement of the relative frequency spectrum relative to the frequency of the excitation source, sometimes information technology is not necessary to employ an expensive THz source and THz detector. Instead, an ultraviolet, visible, or infrared excitation source and corresponding detector tin be used. A combination of prisms and gratings is used to widen the field of view at loftier resolution. The resolution of the system is iv.945 cm−i (0.149 THz), and the spectral range is 2531.84 cm−1 (75.963 THz). We measured the THz Raman spectra of solid powder, aqueous solutions, and mixtures, and studied the furnishings of environment, container material, and time of measurement on the spectra. The results prove that the system is not significantly afflicted by interference from the water environment and has practiced stability and repeatability. This method tin can be applied in many fields such as material detection and environmental protection. Full article
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Open Admission Advice
Liquid Crystal-Embedded Hollow Core Fiber Temperature Sensor in Fiber Ring Laser
Viewed by 583
Abstruse
An optical fiber temperature sensor based on Mach–Zehnder interferometer and thermo-optic effect of the liquid crystal (LC) in cobweb band laser (FRL) system is proposed and experimentally demonstrated. The LC is infiltrated into the core of hollow core fiber, and the resonant wavelength [...] Read more than.
An optical fiber temperature sensor based on Mach–Zehnder interferometer and thermo-optic effect of the liquid crystal (LC) in fiber ring laser (FRL) system is proposed and experimentally demonstrated. The LC is infiltrated into the core of hollow core cobweb, and the resonant wavelength is more sensitive to temperature variation due to the interaction between the incident light and the cavity infiltrating liquid crystal with high thermal lite coefficient. Meanwhile, the FRL system was further used to make the sensor take good functioning in the instance of high signal-to-racket ratio (∼35 dB), narrow one-half-peak width (FWHM = 0.fifteen nm), and loftier sensitivity in the temperature range from xx °C to 50 °C, with the maximum sensitivity of 1.318 nm/°C. As far as we know, in the FRL organisation, the liquid crystal fabric has a better temperature sensing performance than the previous fiber. Nevertheless, the organization has the advantages of good repeatability, depression cost, simple product, small volume, high sensitivity. In marine microbial civilisation and detection, it is necessary to carry out high sensitivity measurement inside a modest temperature variation range. This reliable and fantabulous temperature performance has a potential application prospect. Full article
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Open Access Commodity
Trace CHiv Gas Detection Based on an Integrated Spherical Photoacoustic Prison cell
Cited by 1 | Viewed by 863
Abstract
This paper presents an integrated spherical photoacoustic cell (SPAC) for trace methane (CH4) gas detection. Theoretical assay and counterpart simulations are carried out to analyze the audio-visual field distribution of the SPAC at resonant and non-resonant modes. The finite element simulation [...] Read more.
This paper presents an integrated spherical photoacoustic cell (SPAC) for trace methane (CHfour) gas detection. Theoretical analysis and counterpart simulations are carried out to analyze the audio-visual field distribution of the SPAC at resonant and non-resonant modes. The finite element simulation results based on COMSOL show that the first-order radial resonant frequency and second-society angular resonant frequency are 24,540 Hz and xviii,250 Hz, respectively, which testify practiced agreements with the formula analysis results. The integrated SPAC, together with a high-speed spectrometer and a distributed feedback (DFB) laser source, makes upwardly a photoacoustic (PA) spectroscopy (PAS) system, which is employed for CH4 detection. The minimum detection limit (MDL) is measured to exist 126.9 parts per billion (ppb) at an average time of 1000 south. The proposed SPAC has an integrated, miniaturized and all-optical structure, which can be used for remote and long-distance trace gas detection. Full article
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Open up Access Article
Investigation of Stray Radiation Suppression in Infrared Imaging Organisation Using a Novel Broadband and High-Absorption Ceramic Coating
Cited by 1 | Viewed by 851
Abstract
Aiming at addressing the vulnerability of the infrared imaging opto-mechanical system to stray radiation interference caused by an external light amplification by stimulated emission of radiation, a new method with a broadband and high-absorptivity ceramic coating on the inner wall of the organisation is proposed to reduce the stray [...] Read more.
Aiming at addressing the vulnerability of the infrared imaging opto-mechanical system to stray radiation interference caused past an external laser, a new method with a broadband and high-absorptivity ceramic coating on the inner wall of the arrangement is proposed to reduce the stray radiations intensity, which is helpful to improve the imaging quality of the detection image. Based on plasma electrolytic oxidation (PEO) engineering, the grooming method and properties of a novel ceramic blanket are studied, and a long-wave infrared imaging optical system with high-absorption ceramic blanket is designed and developed. It is verified for the first time that the high-absorption ceramic coating can suppress the devious radiation in the infrared opto-mechanical system, and the effect of laser incident power and angle on the stray radiation is investigated. The experimental results show that the ceramic blanket tin can achieve 95.4% high absorption in the wavelength range of 0.2–16 μm, which can evidently suppress the devious radiation in the opto-mechanical system of infrared imaging caused past light amplification by stimulated emission of radiation. The calculation of the stray radiations suppression ratio shows that, compared with the instance without blanket, the stray radiation intensity in the organization tin can be reduced by 70% using the ceramic coating. Full article
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Open Access Commodity
fNIRS Signal Classification Based on Deep Learning in Stone-Paper-Scissors Imagery Task
Cited past 3 | Viewed by 1052
Abstruse
To explore whether the brain contains pattern differences in the rock–paper–pair of scissors (RPS) imagery task, this newspaper attempts to classify this task using fNIRS and deep learning. In this report, we designed an RPS task with a total elapsing of 25 min and 40 [...] Read more than.
To explore whether the brain contains pattern differences in the rock–paper–scissors (RPS) imagery chore, this paper attempts to classify this task using fNIRS and deep learning. In this study, we designed an RPS task with a total duration of 25 min and 40 south, and recruited 22 volunteers for the experiment. We used the fNIRS acquisition device (FOIRE-3000) to tape the cerebral neural activities of these participants in the RPS task. The time series classification (TSC) algorithm was introduced into the fourth dimension-domain fNIRS signal classification. Experiments testify that CNN-based TSC methods tin accomplish 97% accurateness in RPS classification. CNN-based TSC method is suitable for the classification of fNIRS signals in RPS motor imagery tasks, and may find new application directions for the development of brain–computer interfaces (BCI). Full article
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Open up Access Article
Simultaneous Measurement Method and Fault Analysis of Six Degrees of Freedom Motion Errors of a Rotary Centrality Based on Polyhedral Prism
Cited past 1 | Viewed by 485
Abstract
A novel method is proposed for measuring the half-dozen degrees-of-liberty (DOF) geometric motion errors of a rotary axis based on a polyhedral prism. An fault-sensitive unit which consists of a polyhedral prism and a planar reflector, is designed to carry out measurement of [...] Read more.
A novel method is proposed for measuring the six degrees-of-freedom (DOF) geometric motion errors of a rotary centrality based on a polyhedral prism. An error-sensitive unit which consists of a polyhedral prism and a planar reflector, is designed to carry out measurement of all six DOF errors, including the athwart positioning error, the tilt move error around the Y axis, the tilt motion error around the Ten axis, the radial move fault along the Ten and Y axes, and the centric motility error forth the Z axis. The mathematical error model, including the six DOF geometric movement errors of the rotary axis, the installation errors between the polyhedral prism and the rotary centrality, the manufacturing errors of the polyhedral prism, and the position errors of the sensors, are established. The effectiveness of the proposed method and the compensation model was simulated and experimentally verified. Full article
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Open Access Article
A Fast Point Clouds Registration Algorithm for Laser Scanners
Cited by 2 | Viewed by 810
Abstract
Bespeak clouds registration is an important pace for laser scanner data processing, and there accept been numerous methods. Still, the existing methods oft suffer from low accuracy and low speed when registering large point clouds. To meet this claiming, an improved iterative closest [...] Read more.
Point clouds registration is an of import step for laser scanner information processing, and there have been numerous methods. However, the existing methods often suffer from low accuracy and low speed when registering large point clouds. To meet this claiming, an improved iterative closest point (ICP) algorithm combining random sample consensus (RANSAC) algorithm, intrinsic shape signatures (ISS), and 3D shape context (3DSC) is proposed. The proposed method firstly uses voxel grid filter for down-sampling. Next, the feature points are extracted by the ISS algorithm and described past the 3DSC. Afterwards, the ISS-3DSC features are used for crude registration with the RANSAC algorithm. Finally, the ICP algorithm is used for accurate registration. The experimental results show that the proposed algorithm has faster registration speed than the compared algorithms, while maintaining high registration accurateness. Full article
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Open Access Commodity
Advanced Visualization Polarimetric Imaging: Removal of Water Spray Effect Utilizing Circular Polarization
Cited past 2 | Viewed past 547
Abstract
Circular polarization (CP) memory is a well-known phenomenon whereby natural light becomes partially circularly polarized after scattering past water spray several times, and the circularly polarized land can be well preserved within a certain propagation altitude. In this study, a CP imaging method [...] Read more.
Circular polarization (CP) retentiveness is a well-known miracle whereby natural lite becomes partially circularly polarized afterwards scattering by water spray several times, and the circularly polarized state can exist well preserved within a certain propagation distance. In this report, a CP imaging method combined with the multi-scale assay in the frequency domain is proposed to enhance the vision in rainy atmospheric condition. The images were first decomposed into multi-scales. CP characteristics of light were employed in the low-frequency parts to improve the quality of images in rainy conditions, and the high-frequency parts compensated specific construction data. Experimental results demonstrate that the proposed method can remove the water spray result thereby improving the vision of degraded rainy-day images. Total article
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Open Access Article
Shape Optimization of an Open Photoacoustic Resonator
Viewed by 594
Abstract
Photoacoustic (PA) measurements with open resonators commonly provide poor detection sensitivity due to signal leakage at the resonator opening. We take recently demonstrated three different approaches for modelling the photoacoustic point of open resonators. In this piece of work, one of the approaches is applied [...] Read more than.
Photoacoustic (PA) measurements with open resonators ordinarily provide poor detection sensitivity due to betoken leakage at the resonator opening. Nosotros have recently demonstrated three dissimilar approaches for modelling the photoacoustic indicate of open resonators. In this work, one of the approaches is applied for the optimization of the geometry of the T-shaped resonator for improved signal strength and thus sensitivity. The results from the numerical optimization show an increase in the photoacoustic point by a factor of approximately vii.23. They are confirmed using numerical methods other than the ane applied for the optimization and past experimental measurement. The measurement shows an increase in the photoacoustic signal by a factor of approximately ii.34. Full article
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Open Access Review
Noise Measurement and Reduction in Way-Locked Lasers: Fundamentals for Low-Noise Optical Frequency Combs
Cited by 2 | Viewed by 1015
Abstract
After v decades of development, mode-locked lasers have become pregnant building blocks for many optical systems in scientific research, industry, and biomedicine. Advances in noise measurement and reduction are motivated for both shedding new calorie-free on the fundamentals of realizing ultra-depression-noise optical frequency [...] Read more.
After five decades of development, mode-locked lasers have go significant building blocks for many optical systems in scientific research, industry, and biomedicine. Advances in noise measurement and reduction are motivated for both shedding new light on the fundamentals of realizing ultra-low-racket optical frequency combs and their extension to potential applications for standards, metrology, clock comparison, and so on. In this review, the theoretical models of dissonance in mode-locked lasers are get-go described. Then, the recent techniques for timing jitter, carrier-envelope phase dissonance, and comb-line noise measurement and their stabilization are summarized. Finally, the potential of the discussed engineering to be fulfilled in novel optical frequency combs, such equally electro-optic (EO) modulated combs, microcombs, and quantum pour laser (QCL) combs, is envisioned. Full article
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Open up Access Review
Retina-like Imaging and Its Applications: A Brief Review
Cited by 1 | Viewed past 1036
Abstruse
The properties of the human eye retina, including space-variant resolution and gaze characters, provide many advantages for numerous applications that simultaneously require a large field of view, high resolution, and real-time performance. Therefore, retina-similar mechanisms and sensors have received considerable attention in contempo [...] Read more.
The properties of the human middle retina, including infinite-variant resolution and gaze characters, provide many advantages for numerous applications that simultaneously crave a large field of view, high resolution, and existent-time performance. Therefore, retina-similar mechanisms and sensors have received considerable attention in recent years. This paper provides a review of state-of-the-art retina-like imaging techniques and applications. Outset, we introduce the principle and implementing methods, including software and hardware, and describe the comparisons between them. And then, we present typical applications combined with retina-similar imaging, including three-dimensional acquisition and reconstruction, target tracking, deep learning, and ghost imaging. Finally, the challenges and outlook are discussed to further study for applied use. The results are beneficial for improve agreement retina-like imaging. Full article
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Open Admission Feature Newspaper Review
Primal Technologies of Photonic Artificial Intelligence Chip Structure and Algorithm
Viewed by 824
Abstract
Artificial intelligence fries (AICs) are the intersection of integrated circuits and artificial intelligence (AI), involving structure design, algorithm analysis, chip fabrication and application scenarios. Due to their fantabulous ability in data processing, AICs evidence a long-term industrial prospect in big information services, cloud [...] Read more.
Artificial intelligence chips (AICs) are the intersection of integrated circuits and artificial intelligence (AI), involving structure design, algorithm analysis, scrap fabrication and application scenarios. Due to their excellent ability in data processing, AICs show a long-term industrial prospect in big data services, deject centers, etc. However, with the believable exhaustion of Moore's Law, the size of traditional electronic AICs (EAICs) is gradually approaching the limit, and an architectural update is highly required. Photonic bogus intelligence chips (PAIC) use lite beam propagation in the silicon waveguide, contributing to a high parallelism configuration, fast calculation speed and low latency. Due to light manipulation, PAICs perform well in anti-electromagnetic interference and energy conservation. This invited paper summarized the recent research on PAICs. The characteristics of different hardware structures are discussed. The current widely used preparation algorithm is given and the Photonic Blueprint Automatic (PDA) simulation platform is introduced. In addition, the authors' related work on PAICs is presented and we believe that PAICs may play a disquisitional role in the deployment of information processing engineering science. Total article
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