Journals >Optoelectronics Letters
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2024
Volume: 20 Issue 7
9 Article(s)
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Research on visual sensitivity characteristics of amor- phous silicon photocells
Yan WANG, Nuo CAI, Xiaodi ZHOU, Yabin LU... and Xinmin and FAN|Show fewer author(s)
This study delves into the feasibility of using amorphous silicon photocells as photosensitive units for retinal prosthe- ses. Firstly, theoretical simulations coupled with experimental results demonstrated its strong light absorption and quantum efficiency within the 300—800 nm range. Subsequently, measurements on itsThis study delves into the feasibility of using amorphous silicon photocells as photosensitive units for retinal prosthe- ses. Firstly, theoretical simulations coupled with experimental results demonstrated its strong light absorption and quantum efficiency within the 300—800 nm range. Subsequently, measurements on its visual sensitivity properties were conducted. The findings revealed that under photopic vision conditions, the photocells could provide the stimu- lating current required for the human retinal nerve cells. Finally, the visual spectral sensitivity curve of the amorphous silicon photocells was assessed, and the results indicated that the spectral sensitivity curve of the amorphous silicon photocells closely mirrors the visual function curve of the human eye under photopic conditions, demonstrating a re- sponse to light across various wavelengths..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 385 (2024)
High-sensitivity photonic crystal fiber sensor based on surface plasmon resonance
Huanting FENG, Jiachen GAO, and Xianbing and MING
In this paper, we propose a photonic crystal fiber (PCF) sensor based on the surface plasmonic resonance (SPR) effect for simultaneous temperature and refractive index (RI) measurement. The coupling characteristics and sensing per- formance of the sensor are analyzed using the full vector finite element method (FEM). TIn this paper, we propose a photonic crystal fiber (PCF) sensor based on the surface plasmonic resonance (SPR) effect for simultaneous temperature and refractive index (RI) measurement. The coupling characteristics and sensing per- formance of the sensor are analyzed using the full vector finite element method (FEM). The sensor provides two channels for independent measurement of RI and temperature. When operating independently, channel I supports y-polarized light with a sensitivity of up to 7 000 nm/RIU for detecting RI, while channel II supports x-polarized light with a sensitivity of up to 16 nm/°C for detecting temperature. Additionally, we investigate the influence of gold layer thickness on the sensing performance to optimize the sensor..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 393 (2024)
Graphene oxide-coated microbottle resonators for relative humidity sensing
Zain Huda Adnan, Batumalay Malathy, Md Johari Md Ashadi, Abdul Rahim Hazli Rafis, and Wadi Harun and Su-laiman
Graphene oxide (GO) is a 2D coating material used to improve fiber optics sensors’ response to relative humidity. Mi- crobottle resonators (MBRs) have garnered more attention as sensing media structures. An MBR with a 190 μm di- ameter was coated with GO. Then, tapered fiber light coupling was used to investigate the rGraphene oxide (GO) is a 2D coating material used to improve fiber optics sensors’ response to relative humidity. Mi- crobottle resonators (MBRs) have garnered more attention as sensing media structures. An MBR with a 190 μm di- ameter was coated with GO. Then, tapered fiber light coupling was used to investigate the relative humidity sensing performance in the range of 35—70%RH at 25 °C. The MBR showed a higher Q factor before and after GO coating. The sensitivity of 0.115 dB/%RH was recorded with the 190 μm GO-coated MBR sample compared to a sensitivity of 0.022 dB/%RH for the uncoated MBR sample. These results show that the MBR can be used in fiber optic sensing ap- plications for environmental sensing..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 400 (2024)
Ultrasensitive plasmonic sensor based on MDM waveguide containing Persian Orsi window cavities for refractive index and blood plasma sensing
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We developed a plasmonic refractive index (RI) with ametal-dielectric-metal (MDM) structure that utilizes two Persian Orsi windows-like separated cavities with a high figure of merit (FoM) and ultrasensitivity. The simulated and optimized Ag-air-Ag MDM sensor for surface plasmon resonance (SPR) offers high RI sensitiviWe developed a plasmonic refractive index (RI) with ametal-dielectric-metal (MDM) structure that utilizes two Persian Orsi windows-like separated cavities with a high figure of merit (FoM) and ultrasensitivity. The simulated and optimized Ag-air-Ag MDM sensor for surface plasmon resonance (SPR) offers high RI sensitivity (SRI) and the ability to detect blood plasma concentration (BPC). The results verified that structural parameters have an effect on SRI, full width at half maximum (FWHM),FoM, sensitivity of blood plasma (Sp) for right and left peaks, whose values are 1 345.45 nm?RIU?1, 32 nm, 42.04 RIU?1, 0.26 and 0.19 nm?L?g-1, respectively. The proposed design opens a new horizon in sensor devel- opment..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 406 (2024)
Tuning the optoelectronic properties for small organic compounds as organic solar cell applications
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Recently, organic solar cells have attracted the attention of many researchers owing to flexibility, low cost, light weight and large-area applications, and significant improvement in the power conversion efficiency (PCE). In this work, we designed chains from organic compounds as donors and replaced the core unit in eRecently, organic solar cells have attracted the attention of many researchers owing to flexibility, low cost, light weight and large-area applications, and significant improvement in the power conversion efficiency (PCE). In this work, we designed chains from organic compounds as donors and replaced the core unit in each series with a variety of acceptors in order to enhance their optical and electronic characterization and performance for power conversion ef- ficiencies in organic solar cells. We utilized density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to investigate the geometry optimization by using the Gaussian 09 program. Both electronic and op- tical properties were determined, which involve the lowest unoccupied molecular orbital (LUMO) and the highest oc- cupied molecular orbital (HOMO) levels, the band gap energy, maximum absorption wavelength (λmax), open circuit voltage ( Voc), and light harvesting efficiency (LHE). Our evaluation denotes that the small compounds suggested are predicted to exhibit the best performance compared to the first series (SC1), like a lower band gap energy, a lower HOMO energy level, a greater absorption range, and a larger PCE..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 412 (2024)
CS-FSCL decoding algorithm of polar codes based on critical sets
Jianguo YUAN, Fengguo ZHANG, Jingjie HE, and Yu and PANG
In order to reduce the number of redundant candidate codewords generated by the fast successive cancellation list (FSCL) decoding algorithm for polar codes, a simplified FSCL decoding algorithm based on critical sets (CS-FSCL) of polar codes is proposed. The algorithm utilizes the number of information bits belonging tIn order to reduce the number of redundant candidate codewords generated by the fast successive cancellation list (FSCL) decoding algorithm for polar codes, a simplified FSCL decoding algorithm based on critical sets (CS-FSCL) of polar codes is proposed. The algorithm utilizes the number of information bits belonging to the CS in the special nodes, such as Rate-1 node, repetition (REP) node and single-parity-check (SPC) node, to constrain the number of the path splitting and avoid the generation of unnecessary candidate codewords, and thus the latency and computational complexity are reduced. Besides, the algorithm only flips the bits corresponding to the smaller log-likelihood ratio (LLR) values to generate the sub-maximum likelihood (sub-ML) decoding codewords and ensure the decoding performance. Simulation results show that for polar codes with the code length of 1 024, the code rates of 1/4, 1/2 and 3/4, the proposed CS-FSCL algorithm, compared with the conventional FSCL decoding algorithm, can achieve the same decoding performance, but reduce the latency and computational complexity at different list sizes. Specifically, under the list size of L=8, the code rates of R=1/2 and R=1/4, the latency is reduced by 33% and 13% and the computational complexity is reduced by 55% and 50%, respectively..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 418 (2024)
Small object detection on highways via balance feature fusion and task-specific encoding network
Minming YU, Sixian CHAN, Xiaolong ZHOU, and Zhounian and LAI
Detecting small objects on highways is a novel research topic. Due to the small pixel of objects on highways, tradi- tional detectors have difficulty in capturing discriminative features. Additionally, the imbalance of feature fusion methods and the inconsistency between classification and regression tasks lead to poorDetecting small objects on highways is a novel research topic. Due to the small pixel of objects on highways, tradi- tional detectors have difficulty in capturing discriminative features. Additionally, the imbalance of feature fusion methods and the inconsistency between classification and regression tasks lead to poor detection performance on highways. In this paper, we propose a balance feature fusion and task-specific encoding network to address these is- sues. Specifically, we design a balance feature pyramid network (FPN) to integrate the importance of each layer of feature maps and construct long-range dependencies among them, thereby making the features more discriminative. In addition, we present task-specific decoupled head, which utilizes task-specific encoding to moderate the imbalance between the classification and regression tasks. As demonstrated by extensive experiments and visualizations, our method obtains outstanding detection performance on small object detection on highways (HSOD) dataset and AI-TOD dataset..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 424 (2024)
Key points and visible part fusion attention network for occluded pedestrian detection in traffic environments
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Aiming at the problem of low detection accuracy of occluded pedestrian in traffic environments,this paper proposes a key points and visible part fusion network for ocluded pedestrian detection.The proposed algorithm constructs two attention modules by introducing human key points and the bounding box of visible parts rAiming at the problem of low detection accuracy of occluded pedestrian in traffic environments,this paper proposes a key points and visible part fusion network for ocluded pedestrian detection.The proposed algorithm constructs two attention modules by introducing human key points and the bounding box of visible parts respectively,which suppresses the oc- cluded parts in the channel features and spatial features of pedestrian features respectively.Experimental results on CityPersons and Caltech datasets demonstrate the effectiveness of the proposed algorithm.The missing rate(MR)is re- duced to 40.78 on the Heavy subset of the CityPersons dataset and surpasses many outstanding methods..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 430 (2024)
Learning background restoration and local sparse dic- tionary for infrared small target detection
Yue HE, Rui ZHANG, Chunmei XI, and Hu and ZHU
This paper proposes a method for learning background restoration for infrared small target detection, employing a lo- cal sparse dictionary alongside an equalized structural texture representation. The method is specifically designed for the detection of small infrared targets, accommodating various levels of brightnesThis paper proposes a method for learning background restoration for infrared small target detection, employing a lo- cal sparse dictionary alongside an equalized structural texture representation. The method is specifically designed for the detection of small infrared targets, accommodating various levels of brightness, spatial size, and intensity. Our proposed model intelligently combines global low-rankness and local sparsity to estimate the rank of the background tensor, leveraging spatial and structural information to overcome the limitations posed by insufficient detailed texture knowledge. Subsequently, a structural texture representation, combining local gradient maps and local intensity maps, is applied to emphasize small objects. By comparing our method with nine advanced and representative approaches and quantifying the comparison using various metrics, the experimental results indicate that our proposed method has achieved favorable outcomes in both quantitative assessments and visual results..
Optoelectronics Letters
- Publication Date: Aug. 23, 2024
- Vol. 20, Issue 7, 437 (2024)
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