Journals >Optoelectronics Letters
Contents
2024
Volume: 20 Issue 12
10 Article(s)
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Design, fabrication and characteristics of optofluidic variable aperture based on electromagnetic-driving
Anning ZHANG, Rui ZHAO, Xian WEI, Zhongcheng LIANG, and Zefeng HAN
An electromagnetic-driving variable liquid aperture is designed and fabricated. It consists of a driving cavity, an optical cavity and a storage chamber, a polydimethylsiloxane (PDMS) elastic film, an annular magnet and a driving coil. The driving cavity is filled with dyeing liquid, while the colorless transparent liqAn electromagnetic-driving variable liquid aperture is designed and fabricated. It consists of a driving cavity, an optical cavity and a storage chamber, a polydimethylsiloxane (PDMS) elastic film, an annular magnet and a driving coil. The driving cavity is filled with dyeing liquid, while the colorless transparent liquid fills the optical cavity and the storage chamber. When applying current, the annular magnet moves downward driven by the magnetic field, leading to deformation of the PDMS film. Being squeezed by the moving magnet with the deforming film, the dyeing liquid flows from the driving cavity into the optical cavity, which contributes to the decrease of the clear aperture diameter in the optical cavity. Our proposed aperture performs continuous variable ability up to 2.775 mm in diameter of clear aperture, when the current increases from 0 to 0.33 A, and its relative transmittance ranges from 98.539% to 22.776%..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 705 (2024)
A laser powered EO sensor for measurement of EMP
Jiahong ZHANG, Chao MA, and Zhuo WANG
This article presents an active electro-optic (EO) modulation electromagnetic pulse (EMP) sensor powered by laser. The sensor simulation model is established, and the temporal response characteristics of the sensor are analyzed based on finite element method (FEM). The laser powered supply circuit and receiving modulatThis article presents an active electro-optic (EO) modulation electromagnetic pulse (EMP) sensor powered by laser. The sensor simulation model is established, and the temporal response characteristics of the sensor are analyzed based on finite element method (FEM). The laser powered supply circuit and receiving modulation circuit are designed and implemented. A monopole antenna is designed and used to revive the EMP. By integrating the supply circuit, the receiving modulation circuit and the antenna together, the sensor is finally fabricated and encapsulated. Experimental results indicate that with the designed laser powered supply circuit, the sensor can operate continuously and stably. The measured standard 1.2/50 μs lightning electromagnetic pulse (LEMP) in the time domain agrees well with the input LEMP voltage waveform. The linear maximum and minimum measurable electric fields of the sensor are 20.8 kV/m and 221 V/m, respectively. All the results demonstrate that the sensor can provide an effective technical means for the measurement of EMP in the time domain..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 709 (2024)
Experimental study on the evolution of bright-dark pulses in a 2 μm mode-locked thulium/holmium co-doped fiber laser
Xiaofa WANG, Jie WANG, and Kunyang ZHAO
We experimentally demonstrate the effects of pump power and polarization state on the evolution of bright-dark pulses (BDPs) in a figure-eight passively mode-locked thulium/holmium co-doped fiber laser (THDFL) using nonlinear amplifying loop mirror (NALM) technology. As the pump power increases from 0.5 W to 1 W, the BWe experimentally demonstrate the effects of pump power and polarization state on the evolution of bright-dark pulses (BDPs) in a figure-eight passively mode-locked thulium/holmium co-doped fiber laser (THDFL) using nonlinear amplifying loop mirror (NALM) technology. As the pump power increases from 0.5 W to 1 W, the BDPs are separated and exhibit a linear increase in the time interval between the bright pulse (BP) and dark pulse (DP), which roughly corresponds to the reciprocal of the modulation frequency in the radio frequency (RF) spectrum. Additionally, the polarization state in the cavity is altered by adjusting the polarization controller (PC), and the central wavelength of spectrum, pulse waveform, and full width at half maximum (FWHM) of BDPs in different states are presented..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 714 (2024)
Design of NV color center fluorescence signal acquisition circuit based on FPGA architecture
Sen ZENG, Shuqiang YANG, Jingyan LIU, Chuang ZHAO, Zhengguo SHANG, and Xianming HE
Nitrogen-vacancy (NV) quantum defects in diamond are sensitive detectors of magnetic fields. The rapid development of NV-center magnetic sensor has higher requirements for high-speed and high-precision data acquisition, weak signal detection and display. However, the existing sensing technologies based on diamond NV ceNitrogen-vacancy (NV) quantum defects in diamond are sensitive detectors of magnetic fields. The rapid development of NV-center magnetic sensor has higher requirements for high-speed and high-precision data acquisition, weak signal detection and display. However, the existing sensing technologies based on diamond NV centers rely on bulky and expensive instruments, which must be replaced by a more compact design. Here we combine NV quantum sensing technology with integrated circuit technology to create a compact and easy-to-operate platform, which includes microwave source module, transistor-transistor logic (TTL) modulation module, digital lock-in amplifier (DLIA) module, etc. In order to confirm the reliability of the experimental platform, we not only tested the performance of each individual module, but also carried out optical detection magnetic resonance (ODMR) experiments. With this platform, we can obtain a magnetic sensitivity of 465 nT/Hz1/2. This experimental platform with convenient operation and low noise has the potential to become an independent magnetic measuring instrument..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 721 (2024)
Constructing a small organic molecule by using the derivative of oxadiazole for photovoltaic applications
K. MEJBEL Hussein, H. AL-TAHER Abdulrsool, A. NAMAH Fayez, and F. AL-BADRY Lafy
Because of their elasticity, light weight, little cost, and wide-area applications, besides a notable increase in power conversion efficiency (PCE), organic solar cells (OSCs) have recently caught the concern of numerous researchers. In the current project, we created a variety of organic small compounds as donor materBecause of their elasticity, light weight, little cost, and wide-area applications, besides a notable increase in power conversion efficiency (PCE), organic solar cells (OSCs) have recently caught the concern of numerous researchers. In the current project, we created a variety of organic small compounds as donor materials by using Gaussian 09. Our design approach entails swapping the core part, which is benzothiadiazole (BT), based on a derivative of oxadiazole, as the terminals on both sides of the prototype compound (RM) with a variety of fragments to improve the electronic and optic characterization and performance for PCE in OSCs. Careful theoretical consideration under density-functional theory (DFT) and time-dependent density functional theory (TD-DFT) at the B3LYP/6-31G(d,p) basis set was made to find the maximum absorption wavelength λmax, the efficiency of light harvesting (LHE), excitation energy (EX), highest occupied molecular orbital (HOMO) and lowest occupied molecular orbital (LOMO) levels, energy band gap (Eg), dipole moment (ρ), the density of state (DOS), ionization potential (IP), electron affinity (EA), fill factor (FF), and open circuit voltage (Voc) of molecules RM and TS studied in a methodical manner. Calculated values revealed that proposed compounds T1—T4 can be encouraging materials for manufacturing OSCs as a donor tiny compound with acceptor PC61BM to predict a rise in PCE owing to their possession of proper values for some optical and electronic features, like the lowest HOMO level, narrower band gaps, and a greater absorption wavelength compared with the reference model RM..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 728 (2024)
Deep localization features of photoluminescence in narrow AlGaN quantum wells
Jianyang DENG, Rui LI, Ya’nan GUO, Junxi WANG, Chengxin WANG, and Ziwu JI
The research prepared two deep ultraviolet (DUV) AlGaN-based multiple quantum well (MQW) samples with the same Al content in the QWs but different well widths (3 nm for Sample A and 2 nm for Sample B). Photoluminescence (PL) measurements reveal that Sample A exhibits only one main PL peak across all measured temperaturThe research prepared two deep ultraviolet (DUV) AlGaN-based multiple quantum well (MQW) samples with the same Al content in the QWs but different well widths (3 nm for Sample A and 2 nm for Sample B). Photoluminescence (PL) measurements reveal that Sample A exhibits only one main PL peak across all measured temperatures, while Sample B displays one main PL peak at low temperatures and two distinct PL peaks at high temperatures. Furthermore, compared with Sample A, Sample B exhibits a more significant temperature-dependent PL peak wavelength blue shift relative to the Varshni curve, a more significant excitation power density-dependent PL peak blue shift accompanied by linewidth broadening, as well as a larger non-radiative recombination related activation energy and higher internal quantum efficiency (IQE). These findings can be explained by the observation that the narrower well width of Sample B induces a more pronounced effect of carrier localization than the wider well width of Sample A, due to the enhanced fluctuation in well width and reduced quantum-confined Stark effect (QCSE)..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 736 (2024)
Preparation of water-soluble fluorescent probe based on copper nanoparticles and its detection of tetracycline in meat
Hasanjan ZULPIYE, Xiaozong DOU, and Hongyan ZHANG
In this study, a water-soluble fluorescent probe based on copper nanoparticles (CuNPs) was synthesized using a hydrothermal method with bovine serum albumin (BSA) (BSA@CuNPs) as a protectant, and it was utilized to efficiently detect the concentration of tetracycline (TC). Upon the addition of TC to the BSA@CuNPs probeIn this study, a water-soluble fluorescent probe based on copper nanoparticles (CuNPs) was synthesized using a hydrothermal method with bovine serum albumin (BSA) (BSA@CuNPs) as a protectant, and it was utilized to efficiently detect the concentration of tetracycline (TC). Upon the addition of TC to the BSA@CuNPs probe, its fluorescence intensity is obviously diminished due to the keto-enol functions C=O group in TC connects with the hydroxyl group on the BSA@CuNPs probe to form a non-fluorescent complex, which can be successfully utilized for detecting TC concentration. Linear range and detection limit for TC detection are 0.1—130 μM and 90 nM. Furthermore, the BSA@CuNPs probe was applied to detect TC concentrations in real meat samples, with recoveries ranging from 95.40% to 102.13%, and the relative standard deviation (RSD) was below 2.73%. Therefore, BSA@CuNPs probe exhibits high sensitivity and selectivity for TC, which will be used for the study of TC analysis in meat..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 741 (2024)
Representation strategy for unsupervised domain adaptation on person re-identification
Hao LI, Tao ZHANG, Shuang LI, Xuan LI, and Xin ZHAO
The task of unsupervised person re-identification (Re-ID) is to transfer the knowledge learned in the source domain with no labels to the target domain with no labels. Due to the significant differences in the background of different datasets, the trained model is challenging to extract person features accurately on unThe task of unsupervised person re-identification (Re-ID) is to transfer the knowledge learned in the source domain with no labels to the target domain with no labels. Due to the significant differences in the background of different datasets, the trained model is challenging to extract person features accurately on unsupervised domain adaptive (UDA). Most UDA methods for person Re-ID use single-image representation (SIR) during the feature extraction. These methods might ignore the difference among the cross-view images with the same identity. For this problem, the joint learning image representation strategy for unsupervised domain adaptation (JLIRS-UDA) is proposed, which takes cross-image representation (CIR) into account for UDA. The network architecture of JLIRS-UDA consists of two networks with branching networks. Each network consists of a shared network and two branching networks, the SIR branch and CIR branch. The two branching networks aim to learn the SIR and CIR, respectively. To ensure the accuracy of the pseudo-label generation, the segmenting dynamic clustering (SDC) method is proposed, which divides the training process into two phases. Precisely, in the first phases, SDC adopts the single image features in the clustering phase to ensure that accurate feature details can be learned. In the second phase, SDC fuses SIR and CIR as the final feature for clustering to interactively promote the SIR branch and CIR branch. JLIRS-UDA learns the SIR and CIR jointly in the UDA task training phase. Compared with the state-of-the-arts methods, the strategy proposed in this paper has achieved a significant improvement of 7.1% mean average precision (mAP) on the tasks of Market-1501(Market) to DukeMTMC- Re-ID (Duke). The slightest improvement in accuracy also achieved +0.8% on Market to MSMT17 (MSMT)..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 749 (2024)
Research on FSO modulation classification algorithm based on deep learning
Xiaoxin LIU, Ming LI, and Zhao LIU
For FSO communication atmospheric turbulence has a large impact on signal modulation, the convolution-profile stellar data image conversion algorithm proposed in this paper performs data conversion on the received constellation maps, so that they retain more original signal feature images. A classification network baseFor FSO communication atmospheric turbulence has a large impact on signal modulation, the convolution-profile stellar data image conversion algorithm proposed in this paper performs data conversion on the received constellation maps, so that they retain more original signal feature images. A classification network based on the channel attention mechanism is proposed to classify the modulated signals by extracting the feature information in the image through the residual structure, and the attention mechanism assigns different weights of the channel features. Under the same data conversion algorithm, the proposed classification network achieves the highest recognition accuracy of 96.286%..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 757 (2024)
Fairness-aware multi-agent reinforcement learning and visual perception for adaptive traffic signal control
Wanqing FANG, Xintian ZHAO, and Chengwei ZHANG
The majority of multi-agent reinforcement learning (MARL) methods for solving adaptive traffic signal control (ATSC) problems are dedicated to maximizing the throughput while ignoring fairness, resulting in a bad situation where some vehicles keep waiting. For this reason, this paper models the ATSC problem as a partiaThe majority of multi-agent reinforcement learning (MARL) methods for solving adaptive traffic signal control (ATSC) problems are dedicated to maximizing the throughput while ignoring fairness, resulting in a bad situation where some vehicles keep waiting. For this reason, this paper models the ATSC problem as a partially observable Markov game (POMG), in which a value function that combines throughput and fairness is elaborated. On this basis, we propose a new cooperative MARL method of fairness-aware multi-agent proximity policy optimization (FA-MAPPO). In addition, the FA-MAPPO uses graph attention neural networks to efficiently extract state representations from traffic data acquired through visual perception in multi-intersection scenarios. Experimental results in Jinan and synthetic scenarios confirm that the FA-MAPPO improves fairness while guaranteeing passage efficiency compared to the state-of-the-art (SOTA) methods..
Optoelectronics Letters
- Publication Date: Dec. 25, 2024
- Vol. 20, Issue 12, 764 (2024)
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