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Ghaffar A, Ru F, Liu J, Chen GY, Ni J, Liu J, Hussian S, Yu J, Das B, Mehdi M. High pressure sensor based on intensity-variation using polymer optical fiber. Sci Rep 2024; 14:18604. [PMID: 39127761 PMCID: PMC11316769 DOI: 10.1038/s41598-024-69094-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Accepted: 07/31/2024] [Indexed: 08/12/2024] Open
Abstract
Silica fiber under high pressure increases the risk of fiber breakage or permanent deformation, which may cause sensor failure due to mechanical strength limitations. High pressure can also induce birefringence in optical fiber. In this study, we present a simple design and low-cost high pressure sensor using polymer optical fiber (POF) based on the intensity-variation technique. A side-coupling mechanism in the sensor structure is adopted, which varies the intensity with applied pressure. Two POFs are twisted together to create a sensing region where the light is launched in the first fiber and measurement is taken from the second fiber. In sensing phenomena, cladding mode frustrated total internal reflection occurs when pressure increases. Silicone gel is used in the pressure chamber for sealing and preventing leakage. The sensor structure is able to detect high pressure in the MPa range, where we tested up to 4 MPa. For higher sensitivity, twisted and bend structure is analyzed, and sensitivity is achieved at about 432.21 nW/MPa. However, twisted helical structure is adopted to enhance sensing range which is about 50 cm. The proposed high-pressure sensor structure is easier to fabricate and has high stability because it doesn't require any destructive method as compared to other conventional methods.
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Affiliation(s)
- Abdul Ghaffar
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, 78 North Jiuhua Road, Quzhou, 32400, Zhejiang, China
| | - Fei Ru
- Baoji Cigarette Factory, China Tobacco Shaanxi Industrial Co., Ltd., Baoji, China
| | - Jingming Liu
- Baoji Cigarette Factory, China Tobacco Shaanxi Industrial Co., Ltd., Baoji, China
| | - George Y Chen
- Guangdong and Hong Kong Joint Research Centre for Optical Fiber Sensors and Key Laboratory of Optoelectronic Devices and Systems of the Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Jiasheng Ni
- Laser Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250014, China
| | - Jun Liu
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, 78 North Jiuhua Road, Quzhou, 32400, Zhejiang, China.
| | - Sadam Hussian
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, 78 North Jiuhua Road, Quzhou, 32400, Zhejiang, China.
| | - Jianping Yu
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, 78 North Jiuhua Road, Quzhou, 32400, Zhejiang, China
| | - Bhagwan Das
- Design and Creative Technology Vertical, Torrens University, Ultimo 2007, New South Wales, Australia, Torrens University, New South Wales, Australia
| | - Mujahid Mehdi
- Faculty of Design, Aror University of Art Architecture Design and Heritage Sindh, Sukkur, Sindh, 65200, Pakistan.
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Gui X, He S, Wang Y, Fu X, Guo Y, Li Z. Anti-noise UWFBG-array enhanced DAS system using double-pulse-based time-domain adaptive delay interference. OPTICS LETTERS 2023; 48:1814-1817. [PMID: 37221773 DOI: 10.1364/ol.486149] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 02/25/2023] [Indexed: 05/25/2023]
Abstract
An anti-noise interrogation technique for ultra-weak fiber Bragg grating (UWFBG)-based distributed acoustic sensing (DAS) systems is proposed and demonstrated using double-pulse-based time-domain adaptive delay interference. This technique breaks the limitation that the optical path difference (OPD) between the two arms of the interferometer should be completely matched with the entire OPD between the adjacent gratings in the traditional single-pulse system. The length of the delay fiber in the interferometer can be reduced, and the double-pulse interval can adapt flexibly to the UWFBG array with different grating spacing. The acoustic signal is restored accurately when the grating spacing is 15 m or 20 m by the time-domain adjustable delay interference. Moreover, the noise induced by the interferometer can be suppressed significantly as compared to using a single pulse, and above 8-dB signal-to-noise ratio (SNR) enhancement can be obtained without any extra optical devices when the noise frequency and the vibration acceleration are below 100 Hz and 0.1 m/s2, respectively.
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Li J, Wang Y, Xiao L, Liu X, Jin B. SNR enhancement with a non-local means image-denoising method for a Φ-OTDR system. APPLIED OPTICS 2023; 62:2283-2291. [PMID: 37132867 DOI: 10.1364/ao.484908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Orthogonal pulse pairs generated by the polarization beam splitter (PBS) and the polarization maintaining-optical switch (PM-PSW) can effectively suppress the polarization fading in phase-sensitive optical time-domain reflectometry (Φ-OTDR) systems, but the PM-PSW also brings a lot of noise when switching the optical path periodically. Therefore, a non-local means (NLM) image-processing method is proposed to enhance the signal-to-noise ratio (SNR) of a Φ-OTDR system. Compared with the existing traditional noise reduction methods based on the one-dimensional signal, the method makes full use of redundant texture and self-similarity of multidimensional data. The NLM algorithm can obtain the estimated denoising result value of current pixels by the weighted average of pixels with similar neighborhood structures in the Rayleigh temporal-spatial image. To validate the effectiveness of the proposed approach, we have carried out experiments on the actual signals obtained from the Φ-OTDR system. In the experiment, a sinusoidal waveform of 100 Hz is applied at 20.04 km of the optical fiber as a simulated vibration signal. The switching frequency of PM-PSW is set to 30 Hz. The experimental result shows that the SNR of vibration positioning curve is 17.72 dB before denoising. After using the NLM method based on image-processing technology, the SNR reaches 23.39 dB. Experimental results demonstrate that this method is feasible and effective in improving SNR. This will help to realize accurate vibration location and recovery in practical applications.
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Nunes T, da Silva HP. Characterization and Validation of Flexible Dry Electrodes for Wearable Integration. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23031468. [PMID: 36772507 PMCID: PMC9921656 DOI: 10.3390/s23031468] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/18/2023] [Accepted: 01/24/2023] [Indexed: 05/27/2023]
Abstract
When long-term biosignal monitoring is required via surface electrodes, the use of conventional silver/silver chloride (Ag/AgCl) gelled electrodes may not be the best solution, as the gel in the electrodes tends to dry out over time. In this work, the electrical behaviour and performance of dry electrodes for biopotential monitoring was assessed. Three materials were investigated and compared against the gold-standard Ag/AgCl gelled electrodes. To characterize their electrical behaviour, the impedance response over the frequency was evaluated, as well as its signal to noise ratio. The electrodes' performance was evaluated by integrating them in a proven electrocardiogram (ECG) acquisition setup where an ECG signal was acquired simultaneously with a set of dry electrodes and a set of standard Ag/AgCl gelled electrodes as reference. The obtained results were morphologically compared using the Normalised Root Mean Squared Error (nRMSE) and the Cosine Similarity (CS). The findings of this work suggest that the use of dry electrodes for biopotential monitoring is a suitable replacement for the conventional Ag/AgCl gelled electrodes. The signal obtained with dry electrodes is comparable to the one obtained with the gold standard, with the advantage that these do not require the use of gel and can be easily integrated into fabric to facilitate their use in long-term monitoring scenarios.
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Affiliation(s)
- Tiago Nunes
- PLUX Wireless Biosignals, 1050-059 Lisbon, Portugal
- NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal
| | - Hugo Plácido da Silva
- PLUX Wireless Biosignals, 1050-059 Lisbon, Portugal
- Instituto de Telecomunicações, 1049-001 Lisboa, Portugal
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Dejdar P, Záviška P, Valach S, Münster P, Horváth T. Image Edge Detection Methods in Perimeter Security Systems Using Distributed Fiber Optical Sensing. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22124573. [PMID: 35746356 PMCID: PMC9229558 DOI: 10.3390/s22124573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 06/12/2023]
Abstract
This paper aims to evaluate detection algorithms for perimeter security systems based on phase-sensitive optical time-domain reflectometry (Φ-OTDR). Our own designed and developed sensor system was used for the measurement. The main application of the system is in the area the perimeter fencing intrusion detection. The system is unique thanks to the developed motherboard, which contains a field-programmable gate array (FPGA) that takes care of signal processing. This allows the entire system to be integrated into a 1U rack chassis. A polygon containing two different fence types and also cable laid underground in a plastic tube was used for testing. Edge detection algorithms using the Sobel and Prewitt operators are considered for post-processing. The comparison is made based on the signal-to-noise ratio (SNR) values calculated for each event. Results of algorithms based on edge detection methods are compared with the conventional differential method commonly used in Φ-OTDR systems.
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Affiliation(s)
- Petr Dejdar
- Department of Telecommunications, Faculty of Electrical Engineering and Communications, Brno University of Technology, Technická 12, 61600 Brno, Czech Republic; (P.Z.); (S.V.); (P.M.); (T.H.)
- Czech Optical Solutions s.r.o., Vavrečkova 5262, 76001 Zlín, Czech Republic
| | - Pavel Záviška
- Department of Telecommunications, Faculty of Electrical Engineering and Communications, Brno University of Technology, Technická 12, 61600 Brno, Czech Republic; (P.Z.); (S.V.); (P.M.); (T.H.)
- Czech Optical Solutions s.r.o., Vavrečkova 5262, 76001 Zlín, Czech Republic
| | - Soběslav Valach
- Department of Telecommunications, Faculty of Electrical Engineering and Communications, Brno University of Technology, Technická 12, 61600 Brno, Czech Republic; (P.Z.); (S.V.); (P.M.); (T.H.)
| | - Petr Münster
- Department of Telecommunications, Faculty of Electrical Engineering and Communications, Brno University of Technology, Technická 12, 61600 Brno, Czech Republic; (P.Z.); (S.V.); (P.M.); (T.H.)
- Czech Optical Solutions s.r.o., Vavrečkova 5262, 76001 Zlín, Czech Republic
| | - Tomáš Horváth
- Department of Telecommunications, Faculty of Electrical Engineering and Communications, Brno University of Technology, Technická 12, 61600 Brno, Czech Republic; (P.Z.); (S.V.); (P.M.); (T.H.)
- Czech Optical Solutions s.r.o., Vavrečkova 5262, 76001 Zlín, Czech Republic
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Jiang F, Zhang Z, Lu Z, Li H, Tian Y, Zhang Y, Zhang X. High-fidelity acoustic signal enhancement for phase-OTDR using supervised learning. OPTICS EXPRESS 2021; 29:33467-33480. [PMID: 34809158 DOI: 10.1364/oe.439646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Phase-measuring phase-sensitive optical time-domain reflectometry (OTDR) has been widely used for the distributed acoustic sensing. However, the demodulated phase signals are generally noisy due to the laser frequency drift, laser phase noise, and interference fading. These issues are usually addressed individually. In this paper, we propose to address them simultaneously using supervised learning. We first use numerical simulations to generate the corresponding noisy differential phase signals for the given acoustic signals. Then we use the generated acoustic signals and noises together with some real noise data to train an end-to-end convolutional neutral network (CNN) for the acoustic signal enhancement. Three experiments are conduct to evaluate the performance of the proposed signal enhancement method. After enhancement, the average signal-to-noise ratio (SNR) of the recovered PZT vibration signals is improved from 13.4 dB to 42.8 dB, while the average scale-invariant signal-to-distortion ratio (SI-SDR) of the recovered speech signals is improved by 7.7 dB. The results show that, the proposed method can well suppress the noise and signal distortion caused by the laser frequency drift, laser phase noise, and interference fading, while recover the acoustic signals with high fidelity.
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Enhancing Detection Performance of the Phase-Sensitive OTDR Based Distributed Vibration Sensor Using Weighted Singular Value Decomposition. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11041928] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We propose a weighted singular value decomposition (WSVD) to reduce the random noise in the Rayleigh backscattering signal of the phase-sensitive optical time domain reflectometry (Φ-OTDR) to enhance the detection performance of the distributed vibration sensing. A 2D image is formed by assembling the raw Rayleigh backscattering traces into a matrix form, and slowly varying fluctuation and random noise can be removed using the WSVD. Consequently, the location information and the frequency of vibration induced by the external vibration event can be extracted. A vibration event with 9 m spatial resolution is detected along a 2.4 km single mode fiber. The signal-to-noise ratio (SNR) of location information for the 102 Hz physical vibration and the 525 Hz acoustic vibration was found to be 10.7 and 12.2 dB, respectively. The SNR of the vibration events demonstrate an increase of 6–7 dB compared to the conventional method, showing the excellent denoising capability of this new approach.
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Zinsou R, Liu X, Wang Y, Zhang J, Wang Y, Jin B. Recent Progress in the Performance Enhancement of Phase-Sensitive OTDR Vibration Sensing Systems. SENSORS (BASEL, SWITZERLAND) 2019; 19:E1709. [PMID: 30974777 PMCID: PMC6479340 DOI: 10.3390/s19071709] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/25/2019] [Accepted: 03/29/2019] [Indexed: 11/16/2022]
Abstract
Recently, phase-sensitive Optical Time-Domain Reflectometry (Φ-OTDR)-based vibration sensor systems have gained the interest of many researchers and some efforts have been undertaken to push the performance limitations of Φ-OTDR sensor systems. Thus, progress in different areas of their performance evaluation factors such as improvement of the signal-to-noise ratio (SNR), spatial resolution (SR) in the sub-meter range, enlargement of the sensing range, increased frequency response bandwidth over the conventional limits, phase signal demodulation and chirped-pulse Φ-OTDR for quantitative measurement have been realized. This paper presents an overview of the recent progress in Φ-OTDR-based vibration sensing systems in the different areas mentioned above.
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Affiliation(s)
- Romain Zinsou
- Key Laboratory of Advanced Transducers and Intelligent Control Systems (Ministry of Education and Shanxi Province), Taiyuan University of Technology, Taiyuan 030024, China.
| | - Xin Liu
- Key Laboratory of Advanced Transducers and Intelligent Control Systems (Ministry of Education and Shanxi Province), Taiyuan University of Technology, Taiyuan 030024, China.
| | - Yu Wang
- Key Laboratory of Advanced Transducers and Intelligent Control Systems (Ministry of Education and Shanxi Province), Taiyuan University of Technology, Taiyuan 030024, China.
| | - Jianguo Zhang
- Key Laboratory of Advanced Transducers and Intelligent Control Systems (Ministry of Education and Shanxi Province), Taiyuan University of Technology, Taiyuan 030024, China.
| | - Yuncai Wang
- Key Laboratory of Advanced Transducers and Intelligent Control Systems (Ministry of Education and Shanxi Province), Taiyuan University of Technology, Taiyuan 030024, China.
- College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Baoquan Jin
- Key Laboratory of Advanced Transducers and Intelligent Control Systems (Ministry of Education and Shanxi Province), Taiyuan University of Technology, Taiyuan 030024, China.
- State Key Laboratory of Coal and CBM Co-mining, Jincheng 048000, China.
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Shan Y, Ji W, Wang Q, Cao L, Wang F, Zhang Y, Zhang X. Performance Optimization for Phase-Sensitive OTDR Sensing System Based on Multi-Spatial Resolution Analysis. SENSORS 2018; 19:s19010083. [PMID: 30591640 PMCID: PMC6338893 DOI: 10.3390/s19010083] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/20/2018] [Accepted: 12/22/2018] [Indexed: 11/16/2022]
Abstract
This paper proposes and demonstrates a phase-sensitive optical time domain reflectometry (Φ-OTDR) sensing system with multi-spatial resolution (MSR) analysis property. With both theoretical analysis and an experiment, the qualitative relationship between spatial resolution (SR), signal-to-noise ratio (SNR) and the length of the vibration region has been revealed, which indicates that choosing a suitable SR to analyze the vibration event can effectively enhance the SNR of a sensing system. The proposed MSR sensing scheme offers a promising solution for the performance optimization of Φ-OTDR sensing systems, which can restore vibration events of different disturbance range with optimum SNR in merely a single measurement while maintaining the same detectable frequency range.
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Affiliation(s)
- Yuanyuan Shan
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Nanjing 210093, China.
- Institute of Optical Communication Engineering, Nanjing University, Nanjing 210093, China.
| | - Wenbin Ji
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Nanjing 210093, China.
- Institute of Optical Communication Engineering, Nanjing University, Nanjing 210093, China.
| | - Qing Wang
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Nanjing 210093, China.
- Institute of Optical Communication Engineering, Nanjing University, Nanjing 210093, China.
| | - Lu Cao
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Nanjing 210093, China.
- Institute of Optical Communication Engineering, Nanjing University, Nanjing 210093, China.
| | - Feng Wang
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Nanjing 210093, China.
- Institute of Optical Communication Engineering, Nanjing University, Nanjing 210093, China.
| | - Yixin Zhang
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Nanjing 210093, China.
- Institute of Optical Communication Engineering, Nanjing University, Nanjing 210093, China.
- The Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210093, China.
| | - Xuping Zhang
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Nanjing 210093, China.
- Institute of Optical Communication Engineering, Nanjing University, Nanjing 210093, China.
- The Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210093, China.
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Jiang F, Li H, Zhang Z, Zhang Y, Zhang X. Localization and Discrimination of the Perturbation Signals in Fiber Distributed Acoustic Sensing Systems Using Spatial Average Kurtosis. SENSORS 2018; 18:s18092839. [PMID: 30154329 PMCID: PMC6163652 DOI: 10.3390/s18092839] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/15/2018] [Accepted: 08/21/2018] [Indexed: 12/04/2022]
Abstract
Location error and false alarm are noticeable problems in fiber distributed acoustic sensing systems based on phase-sensitive optical time-domain reflectometry (Φ-OTDR). A novel method based on signal kurtosis is proposed to locate and discriminate perturbations in Φ-OTDR systems. The spatial kurtosis (SK) along the fiber is firstly obtained by calculating the kurtosis of acoustic signals at each position of the fiber in a short time period. After the moving average on the spatial dimension, the spatial average kurtosis (SAK) is then obtained, whose peak can accurately locate the center of the vibration segment. By comparing the SAK value with a certain threshold, we may to some degree discriminate the instantaneous destructive perturbations from the system noise and certain ambient environmental interferences. The experimental results show that, comparing with the average of the previous localization methods, the SAK method improves the pencil-break and digging locating signal-to-noise ratio (SNR) by 16.6 dB and 17.3 dB, respectively; and decreases the location standard deviation by 7.3 m and 9.1 m, respectively. For the instantaneous destructive perturbation (pencil-break and digging) detection, the false alarm rate can be as low as 1.02%, while the detection probability is maintained as high as 95.57%. In addition, the time consumption of the SAK method is adequate for a real-time Φ-OTDR system.
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Affiliation(s)
- Fei Jiang
- School of Mechatronics Engineering, Beijing Institute of Technology, Beijing 100081, China.
- Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China.
| | - Honglang Li
- Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China.
| | - Zhenhai Zhang
- School of Mechatronics Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Yixin Zhang
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Nanjing University, Nanjing 210008, China.
| | - Xuping Zhang
- The Key Laboratory of Intelligent Optical Sensing and Manipulation, Nanjing University, Nanjing 210008, China.
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