- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fabrication of Milk Fat Sensor based on Plastic Optical Fiber
摘要： The research about milk fat content based on plastic optical fiber sensor using gamma and spiral spring without cladding configurations has been reported. LED light transmitted through the plastic optical fiber to be received by the phototransistor. Changes in milk fat content affect the light intensity received by the phototransistor. Sensor output voltage amplified by a differential amplifier and then the analog signal converted into the digital signal by the Arduino Uno microcontroller furthermore, the output voltage read on a computer. The milk fat content sample with a percentage of 0.773 % to 4.473 % affect the propagation of light in the core of plastic optical fiber results in power losses that occur so that the light intensity decreases and the output voltage measured becomes smaller. The results showed that the higher the milk fat content, the sensor output voltage decreases. The best measurements obtained on the spiral spring configuration with 4 windings produce value range 0.044 V, sensitivity 11.887 mV/%, and a resolution of 0.084 %. This method is effective as well as efficiently used as milk fat sensor because it has good sensitivity and resolution.
关键词： spiral spring configuration,sensitivity,resolution,gamma configuration,milk fat sensor,plastic optical fiber
更新于2025-09-23 15:19:57
-
Enhancing the Speed and Sensitivity of a Nonlinear Optical Sensor with Noise
摘要： We demonstrate how noise can be turned into a resource for optical sensing using a nonlinear cavity. The cavity is driven by a continuous-wave laser into the regime of optical bistability. Due to the influence of fluctuations, the cavity switches randomly between two metastable states. By analyzing the residence times in these two states, perturbations to the resonance frequency of the cavity can be detected. Here, such an analysis is presented as a function of the strength of the perturbation and of the noise. By increasing the standard deviation of the noise, we find that the detection speed increases monotonically while the sensitivity peaks at a finite value of the noise strength. Furthermore, we discuss how noise-assisted sensing can be optimized in state-of-the-art experimental platforms, relying solely on the minimum amount of noise present in the cavity due to its dissipation. These results open up new perspectives for the ultrafast detection of nanoparticles, contaminants, gases, or other perturbations to the resonance frequency of an optical resonator, at low powers and in noisy environments.
关键词： noise,residence times,nonlinear optical sensor,sensitivity,optical bistability,detection speed
更新于2025-09-23 15:19:57
-
Impact of metal crystallinity-related morphologies on the sensing performance of plasmonic nanohole arrays
摘要： Plasmonic nanohole arrays for biosensing applications have attracted tremendous attention because of their flexibility in optical signature design, high multiplexing capabilities, simple optical alignment setup, and high sensitivity. The quality of the metal film, including metal crystallinity and surface roughness, plays an important role in determining the sensing performance because the interaction between free electrons in the metal and incident light is strongly influenced by the metal surface morphology. We systematically investigated the influence of metal crystallinity-related morphologies on the sensing performance of plasmonic nanohole arrays after different metal deposition processes. We utilised several non-destructive nanoscale surface characterisation techniques to perform a quantitative and comparative analysis of the Au quality of the fabricated sensor. We found empirically how the surface roughness and grain sizes influence the permittivity of the Au film and thus the sensitivity of the fabricated sensor. Finally we confirmed that the deposition conditions that provide both low surface roughness and large metal grain sizes improve the sensitivity of the plasmonic sensor.
关键词： sensitivity,Plasmonic nanohole arrays,biosensing,metal crystallinity,surface roughness
更新于2025-09-23 15:19:57
-
[IEEE 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Daejeon, Korea (South) (2019.7.28-2019.8.1)] 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Multimodal and Multifunctional Plasmonic Nanostructures and Techniques
摘要： State-space current control enables high dynamic performance of a three-phase grid-connected converter equipped with an LCL filter. In this paper, observer-based state-space control is designed using direct pole placement in the discrete-time domain and in grid-voltage coordinates. Analytical expressions for the controller and observer gains are derived as functions of the physical system parameters and design specifications. The connection between the physical parameters and the control algorithm enables automatic tuning. Parameter sensitivity of the control method is analyzed. The experimental results show that the resonance of the LCL filter is well damped, and the dynamic performance specified by direct pole placement is obtained for the reference tracking and grid-voltage disturbance rejection.
关键词： Active damping,current control,LCL filter,grid-connected converter,parameter sensitivity,sensorless state feedback
更新于2025-09-23 15:19:57
-
Modifying twisted nematic LCD screens to create dichromatic visual stimuli with LEDs
摘要： 1. The use of computers to create and display animations/videos in the study of visually-guided behaviors has been instrumental in understanding sensory mechanisms underlying complex traits. Using computer displays scientists are able to create a wide array of colors using three differently colored lights (Red, Green, Blue: RGB). While it is possible to generate scenes with RGB displays that mimic animals’ color perceptual experience, this can be problematic because it requires knowledge of the spectral absorbance of the animals’ photoreceptor classes, which are often unknown and are difficult to obtain. Even then, stimuli are limited to the central part of the visible spectrum (e.g., ultraviolet (UV) stimuli are not possible). 2. We present a cost-effective way of modifying a twisted nematic LCD screen that utilizes colored LEDs, that allows measuring animals’ sensitivity to, and discrimination between, wavelengths of light. It has the benefit of not requiring a-priori knowledge of animals’ photoreceptor classes. An LCD screen can be modified by removing the screen’s back polarizer (behind the liquid crystal layer) and backlighting the screen with LEDs of two different colors. One of the LED colors transmits through a polarizer with a transmission axis parallel to the screen’s front polarizer, and other LED color transmits through a polarizer orthogonal to the first. 3. To test color discrimination one can create a dichromatic stimulus in which both LED colors are ‘ON’ and the current fithrough one LED color is decreased, while the other is constant, which generated a maximum intensity contrast of 1.84 log units in our setup. To test color sensitivity one can create a monochromatic stimulus in which only one LED color is ‘ON’, which generates a contrast similar to the dichromatic stimulus. This technique overcomes many of the limitations of RGB-based LCD screens in a cost-effective way, and allows more accurate testing of the role of color in visually-guided behaviors. Besides the questions in vision research this setup can answer, it can also be used as an outreach tool in classrooms where children can learn about light, color, polarization, and technology.
关键词： twisted nematic LCD screen,spectral sensitivity,polarization,visually-guided behavior,color vision,spectrometer,LED
更新于2025-09-23 15:19:57
-
High-sensitivity laser confocal tomography based on frequency-shifted feedback technique
摘要： Laser confocal tomography faces severe challenges in weak signal detection such as biological tissue imaging and low-re?ection interfaces measurement. An ultra-high sensitive optical confocal tomography based on laser frequency-shifted feedback imaging technology is presented, whose theoretical magni?cation can reach 10 6 notably without using high-gain detectors. In addition, this achievement possesses the same tomographic resolution as conventional laser confocal tomography without the need for spatial ?ltering devices. In this work, supported by theories and experiments, the lateral and vertical resolution, optical sensitivity, and system repeatability of LFCT and traditional LCT are investigated and analyzed quanti?cationally. Finally, comparison on the results of measuring the micro?uidic device and biological tissue sections is conducted.
关键词： Laser confocal tomography,High sensitivity,Frequency-shifted feedback,Optical measurement,Biological specimens imaging
更新于2025-09-23 15:19:57
-
[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - The Full-space Bessel Beam Modulator Based on Pancharatnam-Berry Metasurface
摘要： Time-domain channel characterization (TCC) for de-embedding of an asymmetric fixture is introduced. Two design criteria for the design of a 2x-thru are proposed. Error sensitivity regarding a small error in the S-parameters of the 1x-fixture is analyzed with an insertion loss error-coefficient and a return loss error-coefficient. The TCC procedure, including proposed design criteria and error sensitivity, is also introduced to reduce the error in the TCC application. Three different 2x-thru structures are investigated for the verification of the two proposed design criteria and analyzed for error sensitivity. Test fixtures on a printed circuit boards are fabricated for the experimental verification.
关键词： return loss error-coefficient (RLEC),design criteria,De-embedding,error-coefficient,time-domain channel characterization (TCC),insertion loss error-coefficient (ILEC),error sensitivity
更新于2025-09-23 15:19:57
-
Self-powered infrared detection using a graphene oxide film
摘要： The interaction between water and graphene oxide (GO), including water adsorption and desorption, have been widely used to demonstrate moisture-electric energy transformation (MEET). By taking advantage of water desorption stimulated by infrared (IR) light from a graphene oxide film with a gradient of oxygen-containing groups (O-group), a self-powered IR detection approach that can convert IR light into electric signals is demonstrated. The temperature sensitivity reaches 4.2 mK. With further optimization of the materials and structures, the performance of such self-powered IR detection can be further improved. The mechanism of the detection involving IR/thermal effect on the interaction between vapor molecules and solid materials also has potential applications in thermal detection, thermal energy conversion, and chemical sensing.
关键词： thermal sensitivity,graphene oxide,moisture-electric energy transformation,self-powered,infrared detection
更新于2025-09-23 15:19:57
-
Self-driven all-inorganic perovskite microplatelet vertical Schottky junction photodetectors with a tunable spectral response
摘要： Wavelength-selective perovskite photodetectors (PDs) have many applications in optoelectronic field, such as machine vision, imaging and full-color display. However, the instability of organo-inorganic hybrid perovskite material severely limits the commercialization of perovskite-based PDs. In this work, a more stable all-inorganic perovskite, CsPbBr(3-x)Clx (x = 0, 1, 2, 3) microplatelets (MPs), were employed to fabricate Schottky PDs with a simple vertical structure of ITO/MP/Au. The optimized CsPbBr3 MP Schottky PDs exhibit rapid response speed (75 μs) and very low dark current (2 pA) at zero bias. Meanwhile, the device shows a high on/off ratio (>106), a large specific detectivity (>1012 Jones) and linear dynamic range (LDR = 137 dB) with excellent thermal and long-term stability. Furthermore, a tunable spectral response covering from the ultraviolet to visible range is also demonstrated. These results provide a simple avenue to realize self-driven and spectral tunable all-inorganic perovskite Schottky PDs with good stability.
关键词： all-inorganic perovskite,high temperature tolerance,tunable spectral response,vertical structure Schottky photodetector,weak-light sensitivity
更新于2025-09-23 15:19:57
-
Optical fiber surrounded by a graphene layer as an optical sensor
摘要： An optical sensor composed of a circular cylindrical fiber surrounded by graphene layer is investigated. The thin layer of graphene is located at the core–cladding interface. The cladding is an aqueous material. The conductivity ( ?? ) of the graphene layer is taken as ?? = ??? + j???? is the real and imaginary parts of the conductivity. We consider TE waves to propagate in the structure. Using Maxwell’s equations, the dispersion relation is derived. Also, the sensitivity of the effective refractive index to any changes in the aqueous cladding refractive index is deduced. It is found that the sensitivity of the proposed optical fiber can be dramatically improved with the variation of graphene layer conductivity.
关键词： Optical sensor,Optical fiber,Graphene,Sensitivity
更新于2025-09-23 15:19:57