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Sensors, Circuits and Instrumentation Systems (2018) || Investigation of Optoelectronic Properties of Amorphous Silicon Germanium Photodetectors
摘要： Cost consideration of the development of electronic devices is one of prime importance. One simple approach to lower the cost of production of photovoltaic and detectors is by using low cost materials such as amorphous silicon and germanium. These two semiconductors have different optoelectronic properties, such as energy gap, photoconductivity and absorption coefficient. The use of an alloy from the mixing of silicon with certain percentages of germanium would produce photodetectors with improved electronic characteristics and photoconductivity. A number of a-SiGe alloy thin films with different quantities of germanium have been fabricated using thermal vacuum evaporation technique. Conduction mechanism and activation energy of the prepared samples had been calculated and analyzed. The I–V characteristics, the photogenerated current and detectivity of these samples are subjected to measurement and discussion. Hall measurements are also conducted so to calculate the Hall I–V characteristics, Hall mobility, carrier concentration and type identification of the samples.
关键词： Amorphous silicon germanium photodetector,photoconductivity,detectivity,Hall measurements,activation energy,conduction mechanism
更新于2025-09-16 10:30:52
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Upgrade the Evaluation of the Contribution of the Active Element Cross Section Geometry to the He-Ne Laser Energy Characteristics
摘要： The models for estimating the contribution of the cross section geometry to the active medium gain of the He-Ne laser have been considered in this work. Expanding the range of studied cross sections it has been found that these models were not analytical and demand the approximate calculations. Modern methods and computing tools should clarify the results of 1960–1970 and it will bring to more accurate results. Some the experimental verification was carried out only in a rectangular cross section. Our model have to complicate taking into account the field intensity distribution in the resonator.
关键词： active element cross section geometry,optical measurements,biomedicine,information optics,laser,the active medium gain,homogeneous and unhomogeneous boundary conditions
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing LLC OPTOELECTRONIC MATERIALS AND THIN FILMS: OMTAT 2013 - Kochi, Kerala, India (3–5 January 2013)] - Annealing effects on the structural and electrical properties of pulsed laser deposited BaPbO3 thin films
摘要： Conductive pervoskite BaPbO3 (BPO) ?lms as potential electrodes for ferroelectric / tuneable applications were prepared by pulsed laser deposition technique at 6000C and at 0.1 mbar oxygen partial pressure on fused silica substrates. The structural and electrical properties of the ?lms showed a dependence on annealing temperatures and the high oxygen ambient. XRD and standard four probe method with Hall setup were employed to investigate the dependence of growth conditions on crystal structure, resistivity and the carrier concentration on annealing the BPO thin ?lms. The surface topography was analysed by AFM. The unannealed as deposited ?lms showed the least resistivity of 1.6 x 10?2 ohm cm and a bandgap of 4.1eV.
关键词： BPO,PLD,Hall measurements
更新于2025-09-16 10:30:52
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Mobile Monitoring—Open-Source Based Optical Sensor System for Service-Oriented Turbidity and Dissolved Organic Matter Monitoring
摘要： The protection and sustainable use of aquatic resources require a better understanding of fresh water sources, limnic ecosystems, and oceans. The effects of global change, intensive use of natural resources and the complex interactions between humans and the environment show different effects at different scales. Current research approaches are not sufficient to appropriately take account of the heterogeneity and dynamics of aquatic ecosystems. A major challenge in applied environmental research is to extend methods for holistic monitoring and long-term observation technologies with enhanced resolution over both space and time. In this study, turbidity and the content of dissolved organic matter (DOM) are key parameters, as they are of importance for assessing the health of aquatic ecosystems and the state of ecosystem services (e.g., the provision of drinking water). Photonics and optical sensors as well as integrated circuits and open-source based components open interesting possibilities to overcome the current lack of adaptive and service-oriented sensor systems. An open source based optical sensor system was developed, which enables a user-specific, modular and adaptive in-situ monitoring of the turbidity and the dissolved organic substance content almost in real time. Quantification is based on attenuation or transmission measurements with two narrowband LEDs and corresponding detectors in the ultraviolet (DOM content) and infrared range (turbidity) of the electromagnetic spectrum. The developed in-situ sensor system shows a very high agreement with the results obtained using a laboratory photometer but with less methodological effort. First tests carried out in the area close to the city of Leipzig (Saxony, Germany) show promising results. The in-situ sensor system is able to acquire the optical attenuation with a sampling rate up to 0.1 Hz. Due to the fact that data is visualized directly with the help of web services, even the quality of data collection can be improved by assisting the selection of sampling points or a direct spatio-temporal data feedback. What this approach illustrates is the fact that open-source technologies and microelectronics can now be used to implement resilient and promising sensor systems that can set new standards in terms of performance and usability within applied environmental research.
关键词： internet of things,assisted monitoring,attenuation sensor,water quality,photonics sensing,in-situ measurements
更新于2025-09-16 10:30:52
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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Fiber Wireless A-RoF/IFoF Uplink of 0.4Gb/s 16-QAM and 0.6Gb/s QPSK Over a 32-Element 60GHz Phased Array Antenna for 5G Fronthaul Networks
摘要： We experimentally demonstrate an end-to-end Fiber Wireless A-RoF/IFoF fronthaul link using a 32-element 60GHz phased array antenna and characterize for the first time its linearity using two tone measurements, resulting in an 100Mbd uplink transmission of a 16-QAM signal and a 300Mdb QPSK with beamsteering of 15o degrees across 1km fiber and 1m V-band link, meeting the uplink user-rate KPI-requirements for 5G mmWave networks.
关键词： 5G,Two Tone Measurements,Analog Radio-over-Fiber,Mobile Fronthaul
更新于2025-09-16 10:30:52
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Scanning laser triangulation sensor geometry maintaining imaging condition
摘要： This work deals with the system design, control and the experimental results of a scanning laser sensor in which the optical path is scanned by a novel high performance compact fast steering mirror (FSM). The system design satisfies the Scheimpflug condition even though only the illumination path is scanned, such that an FSM with a small aperture size and high bandwidth can be used. To scan the area of interest with the FSM, raster trajectories are employed, which provide an uniform spatial resolution over the scan area. To track the trajectory a feedback controller is designed using the H-approach, such that a closed loop bandwidth of 1.4 kHz is achieved. The FSM can follow triangular signals up to 200 Hz with the maximum actuation range of ±3?. This enables a framerate of up to two frames per second for an image with 100x100 pixels. With the scanning system a maximum spatial resolution of 60 μm and a scan range of 25 mm can be achieved.
关键词： Optical Sensing and Sensors,Precision measurements,Laser Sensor,Fast Steering Mirror,Scheimpflug Condition,3D Sensor,Absolute measurement,System Design
更新于2025-09-16 10:30:52
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Synergic effect of plasmonic gold nanoparticles and graphene oxide on the performance of glucose sensing
摘要： In this study hybrid nanostructures of Au–graphene oxide (Au–GO) were synthesized via a two-step process and used to modify the glassy carbon electrode (GCE) for electrochemical measurements of glucose. The modified electrode exhibits a fast response less than 4 s, a low detection limit of 0.025 mM and a high signal-to-noise ratio (S/N) of 3.5. The fabricated sensor shows a linear response in a large concentration range from 0.0025 mM to 15 mM with a reproducible sensitivity of 84.53 mA cm?2 mM?1, which is much higher than that of the individual Au, GO and previously reported GO/rGO based sensors. In addition, the biosensor shows excellent results for human serum which agree well with those obtained using a laboratory glucometer. Moreover, the glucose amount in selective commercially available food samples and fresh juices was also successfully measured. The biosensor exhibits excellent selectivity, thermal stability and reproducibility. The enhanced and efficient sensitivity of the developed Au–GO based biosensor may be due to the synergic effects of the plasmonic Au-nanoparticles and GO. The performance of the biosensor suggests that the reported Au–GO hybrid nanostructures can provide a novel platform for developing non-enzymatic biosensors for biomedical and industrial applications.
关键词： hybrid nanostructures,Au–graphene oxide,non-enzymatic biosensor,electrochemical measurements,glucose sensing
更新于2025-09-16 10:30:52
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Application of harmonics imaging to focal spot measurements of the “PETAL” laser
摘要： By using numerical simulations and experimental campaigns on a small-scale laser facility, the concept of the focal spot imaging on harmonics of laser frequency is developed and implemented on the Laser MegaJoule (LMJ)/PETawatt Aquitaine Laser (PETAL) facility. The Two/Three ω Imaging System was activated and validated during the first 2017–2019 interaction campaigns of PETAL on the LMJ. It provides major information on focal spot characteristics on a target. Such an approach could be easily applied to any high-intensity facility in the relativistic intensity regime (>1018 W cm?2).
关键词： PETAL laser,harmonics imaging,high-intensity laser-plasma interaction,focal spot measurements
更新于2025-09-16 10:30:52
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Impedance Spectroscopy Study of Organic Photovoltaic Cells with an Inkjet Printed Hole-Extracting Graphene Oxide Layer
摘要： This paper deals with the study of light conversion efficiency of organic photovoltaic cells with an inkjet-printed graphene oxide layer. The graphene oxide is used in this experiment as a hole-extracting, electron blocking layer in bulk heterojunction organic solar cells based on DPP(TBFu)2:PC60BM blend. It is also studied the influence of the GO reduction (chemically, by UV radiation and by annealing) on the final efficiency of photovoltaic conversion. Power conversion efficiency and the transport of charge carriers are evaluated by measuring of current-voltage characteristics and mainly by impedance spectroscopy analysis. In this regard, using of graphene oxide and its reduced form showed negative influence on the device performance caused by an inefficient charge carrier collection at the short-circuit condition.
关键词： current‐voltage measurements,reduction,impedance spectroscopy,graphene oxide,organic solar cells
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - Auckland, New Zealand (2019.5.20-2019.5.23)] 2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - A Method for Three-Dimensional Measurements Using Widely Angled Stereoscopic Cameras
摘要： Computer vision technologies have become popular tools for performing non-contact measurements. Stereoscopic systems have been used in several applications for length and geometry measurements. Three-dimensional (3D) reconstruction is an essential part of performing 3D measurements. A variety of methods have been developed for 3D reconstruction in stereoscopic systems. Block matching methods are considered as the most suitable option for 3D measurements, but they require the views to be similar for the cameras of a stereoscopic system. To satisfy this need, the cameras of a stereoscopic system should have small angles between their optical axes on the object’s surface. However, it is not always feasible nor desirable to arrange cameras in this way for some applications. We have proposed a new method to address this restriction. Our method uses an initial transform between the images from two cameras to make the views similar. Points on the transformed images are used as initial estimates of matched points in the two camera views. The points are then matched between the two images using an accurate subpixel image registration algorithm. The new method was tested using an object with known dimensions. The maximum measurement error achieved was 0.05 mm with a standard deviation of 0.09 mm for 10 measurements of a 12 mm length. The high accuracy of this method makes it a suitable option for applications that require reliable 3D measurements.
关键词： subpixel,3D reconstruction,block matching,stereoscopic measurements,wide base line cameras,image registration
更新于2025-09-16 10:30:52