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Über dieses Buch

This book gathers selected papers from the first International Conference on Optoelectronics and Measurement (ICOM 2018), held in Hangzhou, China on Oct 18-20, 2018. The proceedings focus on the latest developments in the fields of optics, photonics, optoelectronics, sensors, and related measurement technologies. Addressing hot topics in fibre optics, photo detectors and sensors, it also features illustrations of advanced device technologies, explains measurement principles, and shares cutting-edge scientific and technological findings. Accordingly, readers will gain essential insights into the forefront of these fields, and will find not only important technical data, but also new ideas to inspire their own future research.

Inhaltsverzeichnis

Frontmatter

Fiber Optics, Photonics and Optical Communication

Frontmatter

Large-range Bridge Beam-gap Displacement Sensors Based on Cantilever Beam with Fiber Bragg Grating

The bridge beam-gap between the beam body of the high-speed railway bridge can reach 200–300 mm, and the traditional displacement sensor is inconvenient to measure. A large-range bridge beam-gap displacement sensor based on cantilever beam with fiber Bragg grating (FBG) is proposed in this paper. Based on the structural characteristics of the beam joint, fully utilized the effective space to enlarge the mechanical structure size of the cantilever beam to realize displacement sensing. The cantilever beam displacement sensing is simulated by ANSYS software. The sensor is designed and packaged according to the numerical simulation result. A beam-gap changing device is designed to develop the displacement experiment of the beam-gap. The results show that when the bridge beam-gap displacement varies from 0 to 200 mm, the linear correlation coefficient of the displacement–wavelength curve reaches 0.99852, and the displacement detection sensitivity is 4.53 pm/mm, which meets the requirements of beam-gap displacement monitoring. The sensor is structure simple, easy to package layout, convenient to expand the range by lengthening the cantilever beam, well durability, and suitable for long-term online monitoring applications of large-size beam-gap displacement.

Guohui Lyu, Chunming Bi, Yan Zhang, Chaozheng Wang, Mingyang Wang, Xu Jiang

Internal Photonic Modulation of Various Spatial Polarization Modes Using Digital Laser Transmission Across Fiber Optic Channels

A subsequent feature of the digital laser is the inexpensive ease to generate shapes digitally using electronics, rather than employing costly spatial optical lenses. This leads to a possibility of internally modulating data using digitally generated shapes, specific to a mode of electric field polarizations.

Muhammed Fuzail Khan

Fiber Bragg Grating Thermal Gas Flow Sensor by 980 nm Laser Heating

This paper aims at solving the explosion-proof problem in the field of electronic thermal flow meter measuring gas flow, a new thermal flow sensor based on optical fiber heat transfer instead of heating resistor was developed, fiber Bragg gratings are used in place of conventional thermistors to measure the temperature of gaseous media and heat dissipating units, heated light source using 980 nm semiconductor laser, replacement of traditional heating resistors with photothermal conversion films for all-optical no-electricity measurements, intrinsically safe all-optical measurement design is implemented, the risk of explosion from heating circuits is minimized. Experimental results show good agreement between flow and temperature difference, the average mass flow resolution is 0.072 g/s, the method to increase measurement sensitivity is discussed.

Guohui Lyu, Jinling Zhang, Chaozheng Wang, Keda Wang, Yan Zhang, Xu Jiang

Policy-Based Comparison-Triggered Defragmentation Mechanism for Elastic Optical Networks

Spectrum fragment is one of the most important issues in elastic optical networks (EONs). To solve the shortcomings of traditional defragmentation mechanisms, a policy-based comparison-triggered defragmentation mechanism (P-CTD) is proposed. The improved mechanism will analyze the arrived traffic request and current spectrum resource situation firstly, then compare and judge whether to trigger spectrum defragmentation according to preset policy. Theoretical analysis and numerical simulation results show that compared with the traditional mechanisms, the proposed P-CTD mechanism can reduce the bandwidth blocking probability (BBP) as 8.73% and improve the resource utilization ratio as 15.26%, respectively.

Lingqi Luo, Xiaoling Liu, Jingwen Zhang, Cong Yu, Jianhua Shen

Fabry-Perot Cavity-Based Optical Fiber Pressure Sensor

An optical fiber sensor based on Fabry-Perot cavity is introduced; the Fabry-Perot cavity was fabricated by two collimated fibers with smooth end surfaces. The reflection spectrum of the Fabry-Perot cavity can be changed with the ambient pressure, and the reflection spectrum can be transferred into cavity length; thus, the cavity length can be measured to achieve the sensing of the ambient pressure. For the multi-beam interference of the Fabry-Perot cavity, the reflection spectrum was uniform waves with distinctive peaks and valleys. After the Fabry-Perot cavity was well encapsulated with metal structures, the fiber sensor can withstand high temperature of 150 °C and measure the pressure because the cavity length can be linearly varied with the surrounding pressure and the linear coefficient can be 0.99999. When the Fabry-Perot cavity-based sensor was suffered from the upward and downward pressure from 0 to 71 MPa, the cavity lengths of upward and downward were varied within 15 nm which was equivalent of 0.04 MPa. The repeatability and return difference of the sensor have also been studied and the parameters both verified the good property of this kind of sensor. An optical fiber sensor based on Fabry-Perot cavity is introduced, and the response of the cavity length to the ambient pressure, the repeatability, and return difference of the sensor have been studied.

Hui Li, Qingchao Zhao, Jiasheng Ni, Long Ma, Faxiang Zhang, Chang Wang

Modeling Method of Sunlight Interference Signal

In view of the requirements for the evaluation of the adaptability of the photoelectric system to the complex environment, the sun AC interference signals under various ground background are measured, and the normal analysis of the test data shows that the intensity of the sunlight interference signal conforms to the normal distribution. This paper presents a method for the modeling of the sun AC interference signal, which simulates the characteristics of the number of interference signals, the intensity of the signal, the position of the signal, the relative timing, and the law of change. Finally, the simulation example of the interference signal under the weak, medium, and strong jamming environment is given by synthesizing the various characteristics of the sunlight AC jamming signal. The method presented in this paper can provide technical reference and support for the modeling of sunlight AC interference signal and the evaluation of photoelectric system adaptability under different sunlight and background.

Hao Guo, Na Ma, Weiwei Liang

High-Efficiency Automatic Discovery of Optical Communication Device Based on MDNS

This paper comes from the management needs of optical network equipment. Large-scale optical networks require efficient network management software for management. The automatic discovery of network equipment is the key to implement the intelligent network management system and is the basis of the network management software. The traditional automatic discovery method for network devices is mainly based on the ICMP protocol. When ping the IP address on the network one by one, the detection period is too long and the network load is too heavy, so it is not suitable for real-time device discovery. This paper proposes an automatic discovery method based on MDNS protocol. This paper proves that this method can greatly shorten the automatic discovery time of communication equipment and IP services.

Yuhua Zhang, Xueguang Yuan, Yang’an Zhang, Qin Liu, Yalei Chu

Adaptive Phase Estimation in the Presence of Nonlinear Phase Noise for Carrier Phase Recovery of PM-QPSK Signals in Coherent Optical Receivers

There are a number of architectural choices to improving feedback and feedforward carrier phase recovery (CPR) algorithms: filter length, filter shape, error signal, etc. The optimal choice depends on the relative strengths of phase noise and additive noise. On the other hand, the optimal average length of CPE used for filtering the phase noise estimate is quite subjective. In principle, a short average length enables fast carrier phase tracking, and a longer average length enables large ASE noise tolerance. Consequently, the optimal average length becomes relatively so short in the presence of fiber nonlinearities when phase noise is large to prevent any symbol with occurring large ASE noise from severely distorting the CPE process. This may affect the stability of CPE performance and subsequently causing performance degradation. For the steady performance of CPE in the presence of large phase noise, this paper proposes adaptive filtering technique to detect and isolate symbols with significantly large ASE noise from the filtering process to improve stability and performance of CPE algorithms. The results showed that the proposed adaptive filtering CPE technique combined with normalization processing in CPE provides about 1.0 dB Q-factor performance improvement over the conventional CPE method in mitigating the combined effects of laser linewidth and fiber nonlinearity for coherent phase-modulated optical signals. The technique automatically identifies and eliminates symbols with significantly large noise from the filtering process to improve stability and estimation accuracy of the carrier phase estimators. The complexity of additional hardware required to implement the scheme is quite simple.

Faith Kwaku Deynu, Bo Xu, Evans Wilson Akpari

The Plasmon in Square Quantum-Dot System with Few Atoms

Based on the eigen-equation method, the eigenfunction is produced to seek plasmon modes in square quantum dots with few atoms. Besides the eigenfunction, charge-resonance peaks are also used to find plasmon. In the process of finding plasmon modes, it is found that only parts of the plasmon modes can be found by charge-resonance peaks, and all the plasmon modes can be found by eigen-equation method. Furthermore, the influence of various parameters on the plasmon shows that: the frequency of the plasmon shifts red with the increase of the quantum-dots size and shifts blue with the increase of the electron number. Moreover, the frequency of plasmon increases with the increase of the on-site and the nearest-neighbor Coulomb interaction due to that the excitation of plasmon needs higher energy under stronger Coulomb interaction.

Renglai Wu, Jun Quan, Jiangli Song

Electrophysiological and Phototactic Behavior Studies of Musca domestica

Lighting technologies change the life of human beings and bring various applications in illumination and biological engineering. One case is the phototaxis research by light controlling the spread of insects. Optical methods by phototaxis of ultraviolet light have attracted much attention for capturing and killing Musca domestica. However, the development of an effective and environmentally acceptable light traps is still challenging due to the complex responses of insects to wavelength and intensity. Herein, we developed the LED light source for selectively attracting Musca domestica by investigating spectral sensitivity of their compound eyes through electroretinograms (ERG) signal and the phototactic behavior to different LEDs. The spectral sensitivity of the compound eyes showed that both female and male had a primary peak at 360 nm and a secondary peak at 520 nm. The attraction efficiency of LEDs was compared with different colors (wavelengths), which revealed that purple LED (415 nm) attracted the most of Musca domesticas and will broaden the applications of purple LED in the insect pest control.

Wei-Wei Xu, Shun Kamada, Takanori Kozai, Tao Zheng, Takeshi Fujihara, Tomoya Konishi, Masaru Kamano

High Temperature Sensor Based on Regenerative Fiber Bragg Grating

In this paper, two kinds of gratings are used to represent seed gratings of different intensities, which are obtained by conventional writing (R ≥ 70%) and saturation writing (R ≥ 99%) on low-cost SMF-28 fibers respectively. After same high-temperature annealing process, the performance of the grating with saturation writing is more stable, and it is suitable for making a high temperature sensor. By means of calibration tests, the wavelength of the regenerative grating drifted by 15.3 nm during the temperature rise to 1100 ℃, and its full-scale temperature resolution was 0.073 ℃/pm. In combination with the engineering needs, the high temperature resistant capillary ceramic tube and corundum tube are used to encapsulate the grating; therefore, the high temperature resistance of the regenerative fiber grating is used to fabricate the ceramic packaged fiber grating high temperature sensor. Sensing targets with the temperature range from 0 to 1000 ℃ and an accuracy of 1 ℃ are implemented ultimately.

Guohui Lyu, Yu Sun, Yan Zhang, Chaozheng Wang, Xiaohang Liu, Xu Jiang

Tunable NIR Filter with High Q-Factor Realized by Using TiN as Plasmonic Layer

Surface plasmon filters have a wide range of applications in nano-integrated optics because of simple structure and easy integration. Traditional noble metals used for surface plasmon filters are expensive. In this paper, we propose an infrared filter by using TiN. By adjusting the thickness of the metal replacement layer TiN and the photoresist waveguide layer, a pure 2 μm infrared filter is obtained. The full width at half maximum reaches 21.26 nm. Furthermore, the wavelength of peak of filter can be adjusted conveniently from 0.8 to 2.5 µm by modulating the period. Our study provides a theoretical basis for finding cheap alternatives to the materials used in plasma filters.

Lingli Wang, Jun Tan, Yongming Shan, Guojun Jin, Yuying Wang, Limin Hu, Kai Xu, Yanlong Meng

Research on Cascade Inner Microcavity-Based Fiber Sensor

A multimode interference-based fiber cavity sensor was proposed. It was a single-mode–multimode–single-mode cascaded structure with an inner air cavity. The sensitivities of microcavity-based fiber sensor were theoretically analyzed. The sensitivities of temperature and axial strain were formula derived. A microcavity model was established with COMSOL software to study the sensitivities affecting factors. The transmission modes in cavity wall were analyzed, and the effective refractive indexes of them were simulated. With these simulation results, a conclusion could be obtained that the effective refractive indexes were depended on the mode order and the cavity diameter. The temperature and axial strain sensitivities were decided by the effective refractive indexes, and the size of the cavity was the key factor. The larger the size of the microcavity and the higher of the transmission modes, the higher the sensitivity of the sensor could be obtained. It can be a theoretical guidance to design and fabricate fiber cavity sensors.

Huifang Chen, Hai Wang, Kezhen Rong, Tiantian Chen

Optical Fiber Sensor for Steady Micro-flow Rate Measurement

A fiber sensor with simply a section of SMF inserted in a syringe head for steady micro-flow rate measurement has been proposed and experimentally demonstrated. The end face of the SMF and the measured steady micro-flow is formed as an F-P cavity. The length of the formed F-P cavity is easily be modulated by the fluctuation of the steady micro-flow rate. The experimental results show that the highest sensitivities of steady micro-flow rate is 0.020 nm/(μL/min) and obtained by saline water under 10% concentration at the rate of 100 μL/min.

Zhicheng Zhu, Juan Kang, Qian Zhang, Yi Li, Chunliu Zhao

LEDs, OLEDs and Related Materials

Frontmatter

An Ultrathin Tandem Organic Light-Emitting Diodes with Very Low Driving Voltage and High Efficiency

Low driving voltage, high luminance, and high efficiency are the important parameters of organic light-emitting diodes (OLEDs) for their application of display and lighting. Usually, synthesis of new materials, doping technique and designing suitable device structures were the main methods to use for realizing the aim of the wide application of OLEDs. In this paper, we try to obtain a high efficiency and low driving voltage tandem OLED with ultrathin films through optimizing the thickness of hole transporting layer (HTL), electron transport layer (ETL), emission layer (EML), and charge generation layer (CGL). As a result, we got the ultrathin tandem OLED with a very low driving voltage of 7.44 V, the luminance of 16,080 cd/m2, the current efficiency of 16.08 cd/A, and power efficiency of 6.28 lm/W, respectively. This research not only saves the cost and improves the power efficiency, which may supply a theoretical basis for the development of OLEDs in the lighting field.

Yanhong Deng, Jinjiang Wang, Liezun Chen, Xiangyu Jiang, Ke Xie, Yuqi Peng, Yanqing Li

The Study of Working Mechanism of Organic Heterojunction Charge Generation Layer

The tandem organic light-emitting diodes (tandem OLEDs), which having two or more electroluminescence (EL) units vertically stacked in series through charge generation layer (CGL), were widely used in flat-panel displays and solid state lighting because of their advantages of enhanced current efficiency and luminance at low current densities, as well as their prolonged lifetime as compared to the conventional single-unit devices. In a tandem OLEDs, the CGLs play an important role, serving as the charge generation layer, and it is critical for the performance of tandem OLEDs. It is the basis of fabrication high-efficiency tandem OLEDs to deeply understand the working mechanism of CGL. Organic heterojunctions (OHJs) layers are frequently used as CGLs in the construction of high-efficiency tandem OLEDs. In order to understand the working mechanism of organic heterojunctions CGLs, the device with the structure of glass/ITO/tris(8-hydroxyquino line) aluminium (Alq3) (60 nm)/C60(x nm)/pentacene((40-x) nm)/N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-benzidine (NPB) (40 nm)/Al (100 nm) were successfully fabricated, here the organic heterojunction C60/pentacene was used as CGL. The experiment results demonstrated that the organic heterojunction CGL with the structure of C60 (15 nm)/pentacene (25 nm) with the most effective charge generation ability. By analyzing the carrier transport characteristics in device, the device current can be attributed to the organic heterojunction CGL. Finally, by numerically analyzing the current–voltage (J–V) characteristics of devices, the results showed the charge generation mechanism of organic heterojunction was in accord with quantum tunneling process. The obtained results can help ones deeply understand the working mechanism of organic heterojunction CGLs and fabricate high-efficiency OLEDs.

Feiping Lu, Yuxiang Zhao, Yinglong Shi, Qing Liu, Xiaobin Liu, Weijun Ling

Experimental Research and Theoretical Study of Cesium, Oxygen Activation on Defect AlGaN (0001) Surface

We carry out the Cs, O activation experiment of AlGaN photocathodes and find the photocurrent is different from that of AlGaAs in the Cs, O coadsorption stage of activation. This is mainly due to there are dimers and trenches on the surfaces of AlGaAs photocathodes, and they provide enough position for Cs, O atoms to attach. Then pure surface model and the other two defect surface models with Ga or N vacancy are built. The result shows that the work function on the defect surface will have a significant decline at the stage of O adsorption. Thus, the photocurrent of AlGaN with defect surface will increase obviously at the second activation stage which is consistent with our experiment.

Zesen Liu, Liang Chen, Shuqin Zhang, Qingyang Meng, Zhenhuan Gu, Jing Hua

Preparation of Er3+-Doped NaYF4 and Its First-Principles Analysis

Successfully prepared Er3+-doped NaYF4 micron crystal by hydrothermal method. The experimental results show that the Er3+-doped NaYF4 exhibits a strong up-conversion fluorescence emission. Er3+-doped NaYF4 micron crystals exhibit strong green emission and can be used in phosphors and micro-optical devices. The energy band structure and electron density of NaYF4 before and after doping were studied by first principle calculation. It is verified that NaYF4 is a good up-conversion luminescent material, and the stability of Er3+ ion is enhanced by doping.

Qingyang Meng, Shuqin Zhang, Liang Chen, Zhenhuan Gu, Zesen Liu, Jing Hua

The Comparative Analysis of the LED and High-Pressure Sodium Lamp as Road Lighting

This paper mainly studies the advantages and disadvantages of LED and high-pressure sodium lamp and further evaluates the development trend of public lighting systems by comparing the color temperature, color rendering index, fog permeability, energy efficiency and economic benefits of the two sources.

Jianming Huang, Lei Zhang, Limin Hu, Yanhua Han, Mingzhong Xu, Weipeng He, Bin Ru, Haiyong Chen, Shaoqin Fu, Yu Xia, Yueming Yu, Zhangwan Wang, Qunjie Wu, Yan Shi, Shiyu Wang

Distribution of Quantum Dots in Quantum Dots Enhancement Films

Quantum dots (QDs) enhancement film (QDEF) is a QD contained film, used in LCD system to improve display color quality. The uniformity of QD in QDEF directly affects the color rendering ability of quantum dot display devices. Custom-built equipment was set up for investigating the uniformity. The blue light absorption, the green light conversion efficiency and red light conversion efficiency were used as the tools in judging the uniformity of the QD films. The results showed that the QD concentration is higher in the middle region than edge region, and the conversion efficiency of green light is about twice as high as that of red light.

Yuxue Feng, Zugang Liu, Renshi Chen, Xin Wang, Lei Li, Hong Zhao

Photo Detectors and Solar Cells

Frontmatter

Size Dependent Performances of Organic Photodiode Arrays

Organic photodiode array has recently attracted a lot of attention for large-area light detection applications and imaging. In this work, Organic photodiode 3 × 2 (Sample A), 4 × 3 (Sample B), 5 × 4 (Sample C), and 6 × 5 (Sample D) arrays based on copper phthalocyanine (CuPc)/C60 planar heterojunction in which CuPc used as optical sensitive material were fabricated and characterized. It is found that the dark current density of the device increases as the array increases through experimental data. A circuit model was constructed to analyze the cause of this phenomenon, and an analytical expression between dark current density and array size was obtained.

Chen Liu, Junkang Zhong, Xinda Chen, Yingquan Peng

High Photosensitivity Near-Infrared PhOFETs Based on PbPc:C60 Bulk Heterojunction

Near-infrared (NIR) photosensitivity organic field-effect transistors (PhOFETs) have drawn substantial attention due to their applications in the field of industry and science. It is difficult to fabricate the device with high photosensitivity and high photoresponsivity, which greatly limits their development. In this paper, a high photosensitivity (NIR) PhOFETs based on lead phthalocyanine (PbPc):C60 bulk heterojunction were proposed. For NIR light with a wavelength of 808 nm, the device exhibited a relative high photosensitivity through the applied gate voltage and the maximum photosensitivity as high as 2300, which was attributed to the inherent high exciton dissociation efficiency and the relatively low carrier mobility of the BHJ active layer.

Qinyong Dai, Wenli Lv, Yingquan Peng, Wenli Lv, Sunan Xu, Yi Wei, Lei Sun, Ying Wang

Thickness-Dependent Performance of Photosensitive Organic Field-Effect Transistors Based on Palladium Phthalocyanine

In this study, photosensitive organic field-effect transistors (PhOFETs) based on palladium phthalocyanine (PdPc) active layer with different thickness were fabricated and characterized. The photoelectric measurement results demonstrated that the device with 46.7-nm-thick PdPc film exhibited the best photoresponsivity of 1.47 mA/W and the maximum saturation field-effect mobility of 1.88 × 10−3 cm2/Vs in all devices. In addition, for drain voltage Vd = −50 V and gate voltage Vg = −50 V, the device photosensitivity of 20-nm-thick PdPc film reached a maximum at 5.77 compared with other devices in the same condition. Herein, we assumed that the different characteristics with a series thickness were dependent on the grain size and contact resistances in PdPc films. For which the grain size in PdPc films increased to a certain thickness around 46.7 nm and exhibited improved PhOFETs performances. Hereafter, the performance declined due to increasing contact resistances with thickness.

Juanjuan Zhou, Wenli Lv, Sunan Xu, Yingquan Peng

Channel-Length-Dependent Performances of Planar Photodiodes Based on Perovskite

In this paper, planar photodiodes based on perovskite were fabricated and characterized. We explored the relationship between channel length and photo-generated current. The study demonstrates that the photo-generated current generated by planar photodiode at weak light is hardly affected by the channel length. However, due to the influence of the diffusion mechanism, the photo-generated current gradually increases with the channel length under strong light. Our study provides a reasonable explanation for the diffusion mechanism of photo-generated carriers in horizontal structure.

Guangmeng Liao, Kun Xu, Feiyu Zhao, Fobao Huang, Yuanlong Liang, Lan He, Yingquan Peng, Rongzheng Ding

Green-Light Photoresponsive Organic Field-Effect Transistor by PTCDA/Pentacene Heterojunction

The new organic photoelectric detector with great potential has been widely concerned and researched, especially for the photoresponsive organic field-effect transistor (photOFET). However, it is still rare for the researches on green-light photOFET. This paper aimed at green-light photOFET. The green-light photOFETs were fabricated by utilizing organic heterojunction based on PTCDA and pentacene. Under a green-light illumination (the wavelength is 532 nm), it exhibited a maximum photosensitivity of 56.15 (with power intensity of 16.5 mW/cm2) and a maximum photoresponsivity of 19.62 A/W (with power intensity of 0.0033 mW/cm2), which were greater than that of PTCDA single-layer photOFET. These results indicate that the heterojunction photOFET based on PTCDA and pentacene is proved to be a green-light photodetector with good performance.

Ying Tang, Binghan Song

Bending Characteristics of Flexible Organic Phototransistors Based on Copper Phthalocyanine

Highly photosensitive flexible organic phototransistors (OPTs) with an organic thin film of copper phthalocyanine (CuPc) as an active layer were prepared. The performance was investigated in different bending cycles. The photo responsivity reduced to 147.2 mA/W from the initial 253 mA/W and the photocurrent to 1510 nA from the initial 2300 nA after 20 cycles; while for bending cycle of 100 and 200, the photo responsivity and photocurrent kept almost unchanged.

Huabiao Zhu, Yuhuan Yang, Yingquan Peng, Wenli Lv, Sunan Xu, Yi Wei, Lei Sun, Ying Wang, Fangzhi Guo

Preparation and Characterization of (C6H5C2H4NH3)2PbX4 Perovskite Materials

The organic–inorganic hybrid perovskite is a new material obtained by compounding an inorganic component and an organic component on a molecular structure, and has the advantages of them, so that the material has good electroluminescence and photoluminescence effect, good mechanical processing characteristics, etc. In this paper, we synthesized (C6H5C2H4NH3)2PbX4 (X=Cl, Br, I) by using a liquid phase method. The structure and luminescence properties of perovskite materials were controlled by adjusting the reaction temperature and using different halogen elements. The experimental results show that the (C6H5C2H4NH3)2PbI4 materials obtained at different reaction temperatures have a layered structure, and their crystallization quality decrease with increasing temperature. In addition, when the X ion is replaced by Br and Cl ions, both synthesized materials have an obvious layered crystal structure, indicating that the type of halogen ion does not affect the crystallization process and the layered structure. However, the photoluminescence spectrum peaks of the materials with different halogen ion are obviously different, verifying that the energy band structure of the material can be well regulated by changing the halogen ions.

Meimei Hu, Zugang Liu, Qingyang Meng, Qianmin Dong

Absolute Spectral Responsivity Calibration of Terahertz Detector

Calibrating the absolute spectral responsivity is of great importance, because this guides the design and application of terahertz detectors. In this paper, we build a calibration system, and this system can be used to calibrate absolute spectral responsivity of terahertz detectors at a serial of frequencies such as 0.84, 1.63, 2.52, 4.25 THz et al. The key components of the system include a standard terahertz detector and a terahertz gas laser, and other components such as TPX lens and ultrasensitive voltmeter are also included. The calibration system was employed to calibrate a terahertz detector with the model of 12D-3S-VP produced by Gentec Inc., and the absolute spectral responsivity of 193.8 mV/W at 2.52 THz was obtained. The measurement uncertainty is analyzed to be 6.0%. This work not only offers method and system to terahertz detector calibration, but also contributes to high accuracy terahertz power measurement and terahertz device calibration.

Bin Wu, Hongchao Wang, Peng Wang, Peng Zhang, Wancheng Zhang, Chengping Ying

Sensors and Measurement Technology

Frontmatter

Determining Hole Mobility of Zinc Phthalocyanine Thin Films by Light-Intensity-Dependent Current–Voltage Characteristics

Carrier mobility is a basic parameter of organic semiconductors. In this paper, hole mobility of zinc phthalocyanine (ZnPc) thin films was determined by light-intensity-dependent current–voltage characteristics. Firstly, built-in voltage, Vbi, of the organic diode with the structure of “ITO/zinc phthalocyanine (ZnPc)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)/Al” was measured as 0.45 V by using saturation photovoltage method. Based on the value of Vbi, the hole mobility of ZnPc thin film was (1.619 ± 0.06) × 10−6 cm2 V−1 s−1 by fitting the measured photocurrent–voltage characteristic with the established theory of space-charge-limited photocurrent conduction. The measured carrier mobility coincides with that reported in other literature.

Yinqin Ye, Fobao Huang, Yingquan Peng, Wenli Lv, Sunan Xu, Yi Wei, Lei Sun, Ying Wang

Sensing Inter-dot Tunneling Using Nonlinear Absorption in Coupled Quantum Dots

Tunneling-induced nonlinear absorption properties are investigated in coupled quantum dots. Tunneling causes constructive interference for the fifth nonlinearity and total absorption is enhanced dramatically. The nonlinear absorption provides sensitive detection for inter-dot tunneling.

Aihong Yang, Yan Xu, Yandong Peng

Study on the Pressure of HF Gas Detection in High-Voltage Electrical Equipment by TDLAS Technology

The schematic diagram of the optical cavity design has been introduced in detail; meanwhile, the principle of measuring gas concentration with optical resonator is also introduced. Using the optical cavity spectroscopy technology, the gas component detection system is set up to realize high precision online monitoring of gas components such as HF. The detection system uses narrow line-width semiconductor laser to select the characteristic gas spectrum and output the absorption peak wavelength. Three kinds of gas concentration are measured by time division multiplexing, and the online sampling device of closed loop gas is integrated to complete the monitoring platform of high precision. The system needs the saw-tooth wave of 1 Hz, which can be generated by internal DA of ADSP-403. At the same time, the system needs a modulation signal of about 5 kHz, and the debugging signal with such high frequency cannot be generated by DA of micro-controller itself. The system uses DDS generator AD9850 to generate sinusoidal modulation signal which is superimposed on the saw-tooth wave to drive the laser. The paper has developed the SF6 composition monitoring device based on optical attenuation technology, which provides the new research method for the online monitoring of gas components such as HF with the high accuracy of 3 ppm.

Shiling Zhang, Qiang Yao, Xintian Li, Yunqi Yue

Application Research of Adjustable Frequency DC-Spark in Oil Analysis Spectrometer

In order to improve the excitation efficiency and stability of the oil analysis spectrometer, this paper studies the application of adjustable frequency DC-Spark in oil analysis spectrometer and the feasibility of the excitation source is verified. The adjustable frequency DC-Spark is based on PWM (pulse width modulation) technology. By controlling the duty cycle of the PWM to affect the frequency and average energy of the spectral excitation, the warm-up time is shortened and the excitation frequency is optimized. The performance of the adjustable frequency DC-Spark and the AC arc excitation source were tested respectively in an oil analysis spectrometer system based on the rotating disk electrode (RDE: rotation disk electrode). The standard oil of 0, 10, 50 and 100 ppm of Conostan company was tested. The experimental results show that compared with the AC arc excitation source, the adjustable frequency DC-Spark has better excitation and less heat generation. The test results of Fe, Cu and Mg elements in the 100 ppm oil were taken as examples; the repeatabilities were 3.6, 3.5 and 4.1, and the reproducibilities were 2.6, 5.1 and 1.5, which were better than the detection values of AC arc excitation source.

Zhen Wang, Mingfan Dai, Shenghua Zhou, Bangning Mao, Yanqing Qiu

A Three-Dimensional Measurement Method Based on Binary Structured Light Patterns for Medical Electronic Endoscope

One method for three-dimensional (3D) measurement based on 23 binary structured light patterns is proposed for the medical electronic endoscope in the present study. The patterns are designed by using simple logical operations and tools from combinatorial mathematics. First, we project these patterns onto the objects in proper order, and all the modulated patterns are captured by a CMOS camera. Then, a series of preprocessing methods which contain projector-camera calibration, reflection detection and suppression, radial and tangential distortion correction are used to process these modulated patterns. Finally, we decode the patterns and reconstruct the shape of objects by structured light triangulation. An experimental prototype endoscope is built and the results of experiments on real pig stomach show that the proposed method is effective. The precise of depth measurement at the working distance of 80 mm is better than 0.5 mm.

Pei Tao, JiaMin Xia, Bo Yuan, Liqiang Wang

A Miniaturized Device for Measuring Flexure Angle of Flexible Fiber Data Gloves

Angle measuring devices are widely used in many fields, such as wearable devices, human-computer interaction interfaces, and intelligent surgical robots. Compared with electrical signal sensors, optical angle sensors provide a new way for the implementation of wearable data gloves because they are immune to electromagnetic interference and can be integrated in multiple channels. In this paper, an angle measuring device for flexible fiber data gloves is designed, which is composed of an LED light source, a CMOS image sensor, and two coupling lenses. Through a fiber coupling lens, the divergence angle of the LED light source matches with the numerical aperture of the flexible fiber and high-efficiency energy coupling is achieved. An imaging coupling lens with 3 mm length is used to ensure that each fiber image of the fiber bundles occupies more than 64 pixels on the CMOS photosensitive surface, achieving a 16-bit data accuracy of signal measurement. The experimental results show that the device can measure the angle change of the data gloves of 5 finger flexures at the same time, and the flexure resolution of each finger is better than 0.5°.

Jin Zhang, Liqiang Wang, Bo Yuan, Lei Zhang

Research Progress on Artificial Intelligence Human Sensor

The artificial intelligence technology has achieved great progress recently and has potential in the applications of military, intelligent industry, transportation and logistics, intelligent security check, national security, biomedicine, intelligent agriculture, intelligent services, and so on. Human-like sensor and algorithm are two pillars of artificial intelligence technology, corresponding to the ‘senses’ and ‘brains’ of intelligent machines, respectively. Based on traditional sensor technology, the artificial intelligence human-like sensor combines the novel complementary metal oxide semiconductor (CMOS), micro-electro-mechanical systems (MEMS), nanotechnology, big data and cloud computing, Internet technology, and so on, leading to the great improvement of the sensors performance. In this paper, the artificial intelligence human perception is divided into five categories: vision, hearing, smell, taste, and touch, and corresponding research progress and application of the sensors were introduced.

Tianqi Zhao, Aiming Feng, Shangzhong Jin, Yan Shi, Bin Hou, Yongqiang Yan

Investigation on Oil Spectrum Detection Technology Based on Electrode Internal Standard Method

In order to solve the problem that the internal standard elements cannot be added to the rotating disk electrode (RDE: Rotation disk electrode) oil spectrometer, which leads to the low stability and accuracy of the test results. In this paper, an internal standard detection technique using the components of the electrode itself as the internal standard is proposed. Firstly, the spectrum line of carbon element, which is the main component of the electrode under pulsed arc excitation, is used as the internal standard, and the actual test spectrum data obtained within the standard test time are normalized. Then, according to the internal standard method, the different elements needed to be tested are processed according to the peak-to-bottom ratio method. Finally, the method is applied to the oil analysis spectrometer developed by ourselves. The experimental results show that the test results using the electrode internal standard method are obviously better than those without the electrode internal standard method. The repeatability and reproducibility error of the measured values are within the allowable range of ASTM-D6595, especially the reproducibility and reproducibility of iron, copper, magnesium, aluminum, and so on are better than those of ASTM-D6595 standard. The RSD value is increased by nearly one order of magnitude, which can meet the needs of the actual lubricating oil detection and analysis, and the stability and accuracy are better.

Mingfan Dai, Zhen Wang, Shenghua Zhou, Bangning Mao, Yanqing Qiu

Design of Compact Oil Particle Counter System Based on Microscopic Imaging

In this paper, a compact oil particle counter system based on microscopic imaging and smart camera was developed. An optical lens system with 2 times optical magnification and 105 mm conjugate distance was designed. The image data acquired from the high-definition CMOS module (based on Hi3516A) was processed by a CPU on the camera. A control circuit board was developed to display the results in a TFT screen and control the working process of the whole system. Finally, a compact particle counter system with the optical resolution better than 2 μm was acquired. Compared with similar commercial products as we know, this system was accurate and portable, especially suitable for field and online testing.

Zhonghui Cheng, Bin Shen, Dong Fu, Shangzhi Zhong, Yan Xuan, Tianhu Zhang, Yanqing Qiu

Adaptive Phase Estimation in the Presence of Nonlinear Phase Noise for Coherent Optical Detection

For phase-modulated systems, digital carrier phase estimation (CPE) has been generally accepted as the fundamental solution to suppressing the challenging effects of laser phase noise (LPN). The optimal average length FIR filter used in carrier phase estimation algorithms, which is the best trade-off between tracking the time-varying phase offset and reducing effects of the Gaussian noise, has been identified as crucial to estimating phase reference from consecutive multi-symbols and impacts performance of digital coherent receivers. The optimal average length depends on factors such as laser linewidth and optical signal-to-noise ratio (OSNR) as well as nonlinearities of the channel, factors that are very difficult to observe in actual networks because they differ device by device, channel by channel, and subject to change with time, since their statistical knowledge may be unknown especially in reconfigurable optical systems. This paper proposes a simple adaptive phase estimation scheme that uses a phase noise reference to suitably set the properties of the FIR filter (i.e., average length) in phase tracking circuits under different channel conditions to mitigate the combined effects of both intrinsic laser phase noise and nonlinear phase noise in coherent phase-modulated optical systems.

Faith Kwaku Deynu, Bo Xu, Evans Wilson Akpari

Preparation and Application of Semiconductor Fluorescent Probe

This paper describes the investigation of surface modified CdTe/ZnS nanoparticle as a sensing receptor for Hg2+ ion detection by optical approach. Glutathione-modified CdTe/ZnS nanoparticles were used as a fluorescence sensor for Hg ion which involved in the fluorescence quenching. The experiment results show that fluorescence intensity is the highest when the mol ratio of CdTe and ZnS is 1:2 in nanoparticle structure, and the fluorescence intensity of nanoparticle depends linearly on mercury ion concentration, and the correlation coefficient R = 0.9823, and simulation error less than four percent. This technique demonstrated an effective detection of mercury in aquatic environment.

Xin Wang, Jiaqi Chen, Jie Huang, Yuxue Feng, Zhenhuan Gu, Zugang Liu

Online Monitoring Study for SF6 Composition by Optical Cavity Sensing Technology in High-Voltage GIS

The schematic diagram of optical cavity design has been introduced in detail; meanwhile, the principle of measuring the gas concentration with optical resonator is also introduced. The pressure distribution and the velocity distribution of the optical cavity have been simulated by finite element method. Finally, the field performance of the optical cavity has been tested. Using the optical cavity spectroscopy technology, the gas component detection system is set up to realize high precision online monitoring of gas components such as CO, H2S and HF. The detection system uses narrow line-width semiconductor laser to select the characteristic gas spectrum and output the absorption peak wavelength. Three kinds of gas concentration are measured by time division multiplexing, and the online sampling device of closed loop gas is integrated to complete the monitoring platform of high precision. The paper has developed the SF6 composition monitoring device based on optical attenuation technology, which provides the new research method for the online monitoring of gas components such as CO, H2S and HF with the high accuracy of 3 ppm.

Shiling Zhang, Qiang Yao, Meng Jiang
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