Pub Date : 2025-04-22DOI: 10.1016/j.ijleo.2025.172369
Meryem NINI, Mohamed NOHAIR
This study proposes a novel Chemometric approach for the precise and reliable quantification of aniline using an unmodified carbon paste electrode (CPE), even in the presence of interfering species such as phenol. The proposed methodology integrates partial least squares (PLS), random forest (RF) and ridge regression in a stacked model framework, combined with particle swarm optimization (PSO) for potential selection. To enhance the prediction accuracy, a dynamic correction based on XGBoost was applied, which effectively minimized residual errors and improved model robustness. The model developed demonstrated high performance on the training (R2 = 0.9993, RMSE = 0.6260 and MAE = 0.4773), test (R2 = 0.9979, RMSE = 0.7616 and MAE = 0.6839) and cross-validation datasets (R2 = 0.9988, RMSE = 0.8312 and MAE = 0.5467), thus confirming its stability and reliability. The high coefficient of determination (R2), as well as the low root mean square error (RMSE) and mean absolute deviation (MAE) values, underscore the model's robust predictive capabilities and its capacity to accommodate intricate electrochemical interactions. Moreover, the calculated recovery rates and tolerance limits signify high precision and consistency across varying concentration levels. Utilizing an unmodified EPC, this approach proffers a cost-effective, sensitive, and selective strategy for aniline quantification, rendering it especially well-suited for environmental and industrial monitoring. The model's strong predictive capabilities underscore its potential for real-world contaminant detection, offering a reliable solution for complex analytical environments.
{"title":"Integration of advanced chemometric and machine learning techniques: Stacking model and XGBoost dynamic correction for aniline detection with an unmodified carbon paste electrode","authors":"Meryem NINI, Mohamed NOHAIR","doi":"10.1016/j.ijleo.2025.172369","DOIUrl":"10.1016/j.ijleo.2025.172369","url":null,"abstract":"<div><div>This study proposes a novel Chemometric approach for the precise and reliable quantification of aniline using an unmodified carbon paste electrode (CPE), even in the presence of interfering species such as phenol. The proposed methodology integrates partial least squares (PLS), random forest (RF) and ridge regression in a stacked model framework, combined with particle swarm optimization (PSO) for potential selection. To enhance the prediction accuracy, a dynamic correction based on XGBoost was applied, which effectively minimized residual errors and improved model robustness. The model developed demonstrated high performance on the training (R<sup>2</sup> = 0.9993, RMSE = 0.6260 and MAE = 0.4773), test (R<sup>2</sup> = 0.9979, RMSE = 0.7616 and MAE = 0.6839) and cross-validation datasets (R<sup>2</sup> = 0.9988, RMSE = 0.8312 and MAE = 0.5467), thus confirming its stability and reliability. The high coefficient of determination (R2), as well as the low root mean square error (RMSE) and mean absolute deviation (MAE) values, underscore the model's robust predictive capabilities and its capacity to accommodate intricate electrochemical interactions. Moreover, the calculated recovery rates and tolerance limits signify high precision and consistency across varying concentration levels. Utilizing an unmodified EPC, this approach proffers a cost-effective, sensitive, and selective strategy for aniline quantification, rendering it especially well-suited for environmental and industrial monitoring. The model's strong predictive capabilities underscore its potential for real-world contaminant detection, offering a reliable solution for complex analytical environments.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172369"},"PeriodicalIF":3.1,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1016/j.ijleo.2025.172363
Elhadi Mehallel , Ammar Bouchemel , Djamel Abed
Visible-light communication (VLC) systems adopt orthogonal frequency-division-multiplexing (OFDM) modulation for high-data-rate transmission, as it offers better resistance to multipath fading and inter-symbol interference (ISI). However, a major challenge in ACO-OFDM-based VLC systems is high peak-to-average-power-ratios (PAPRs), which can degrade system performance. This paper proposes a combined chaotic scrambling and µ-nonlinear logarithmic companding transform scheme to solve the high PAPR problem and enhance image transmission quality in ACO-OFDM based-VLC systems. The proposed scheme utilizes the chaotic Arnold’s cat map-based scrambling (ACMS) for shuffling image pixels before modulation to improve image transmission quality and reduce PAPR. Moreover, a µ-modified logarithmic companding transform (µ-MLCT) is investigated to enhance the peak signal-to-noise ratio (PSNR), bit-error-ratio (BER), and reduce PAPR. ACMS can provide both data encryption and PAPR reduction. Simulation results confirm the effectiveness of the proposed scheme, which gives PSNR and BER improvements of about 52 dB and 3.5 dB in SNR, respectively, and achieves a PAPR reduction of about 12 dB. Moreover, it can not only achieve high image transmission security but also improve image quality and reduce PAPR in the ACO-OFDM-based VLC system without affecting PSNR and BER performance.
{"title":"A novel PAPR reduction scheme for image transmission with ACO-OFDM VLC systems using chaotic scrambling and µ-modified logarithmic companding","authors":"Elhadi Mehallel , Ammar Bouchemel , Djamel Abed","doi":"10.1016/j.ijleo.2025.172363","DOIUrl":"10.1016/j.ijleo.2025.172363","url":null,"abstract":"<div><div>Visible-light communication (VLC) systems adopt orthogonal frequency-division-multiplexing (OFDM) modulation for high-data-rate transmission, as it offers better resistance to multipath fading and inter-symbol interference (ISI). However, a major challenge in ACO-OFDM-based VLC systems is high peak-to-average-power-ratios (PAPRs), which can degrade system performance. This paper proposes a combined chaotic scrambling and µ-nonlinear logarithmic companding transform scheme to solve the high PAPR problem and enhance image transmission quality in ACO-OFDM based-VLC systems. The proposed scheme utilizes the chaotic Arnold’s cat map-based scrambling (ACMS) for shuffling image pixels before modulation to improve image transmission quality and reduce PAPR. Moreover, a µ-modified logarithmic companding transform (µ-MLCT) is investigated to enhance the peak signal-to-noise ratio (PSNR), bit-error-ratio (BER), and reduce PAPR. ACMS can provide both data encryption and PAPR reduction. Simulation results confirm the effectiveness of the proposed scheme, which gives PSNR and BER improvements of about 52 dB and 3.5 dB in SNR, respectively, and achieves a PAPR reduction of about 12 dB. Moreover, it can not only achieve high image transmission security but also improve image quality and reduce PAPR in the ACO-OFDM-based VLC system without affecting PSNR and BER performance.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172363"},"PeriodicalIF":3.1,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-18DOI: 10.1016/j.ijleo.2025.172351
P. Pon Matheswari, J. Maria Libiyal, J. Ilavarasi Jeyamalar, B. Ravindran Durai Nayagam
This study investigates the novel proton-transfer system, Adeninium 2,3 pyridine dicarboxylate (ADH+PD-) derived from Adenine and 2,3 pyridine dicarboxylic acid. We determined its structural properties using SCXRD with a space group P1 n1. Frontier molecular orbital reveals distinct localization of HOMO and LUMO, indicating potential intermolecular charge transfers, and provides insights into regions of electron density. The atomic charge analysis results supported the SCXRD and HSA results, showing the formation of noncovalent interactions in organic crystalline salt. The results of the natural bond orbital (NBO) analysis confirmed the existence of (relatively weak) noncovalent interactions between the cation and anion moieties of the organic crystalline salt. UV–visible spectral studies were conducted to assess the suitability of the single crystal for various optical applications, revealing its excellence in linear optical transparency. Furthermore, Electron localization function (ELF), local orbital locator (LOL), and Reduced Density Gradient Analysis (RDG) were studied.
{"title":"Spectral, structural, and theoretical elucidation of a novel adenine-based crystalline salt: Insights from NMR, XRD, DFT, NBO and NLO studies","authors":"P. Pon Matheswari, J. Maria Libiyal, J. Ilavarasi Jeyamalar, B. Ravindran Durai Nayagam","doi":"10.1016/j.ijleo.2025.172351","DOIUrl":"10.1016/j.ijleo.2025.172351","url":null,"abstract":"<div><div>This study investigates the novel proton-transfer system, Adeninium 2,3 pyridine dicarboxylate (ADH<sup>+</sup>PD<sup>-</sup>) derived from Adenine and 2,3 pyridine dicarboxylic acid. We determined its structural properties using SCXRD with a space group P1 n1. Frontier molecular orbital reveals distinct localization of HOMO and LUMO, indicating potential intermolecular charge transfers, and provides insights into regions of electron density. The atomic charge analysis results supported the SCXRD and HSA results, showing the formation of noncovalent interactions in organic crystalline salt. The results of the natural bond orbital (NBO) analysis confirmed the existence of (relatively weak) noncovalent interactions between the cation and anion moieties of the organic crystalline salt. UV–visible spectral studies were conducted to assess the suitability of the single crystal for various optical applications, revealing its excellence in linear optical transparency. Furthermore, Electron localization function (ELF), local orbital locator (LOL), and Reduced Density Gradient Analysis (RDG) were studied.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172351"},"PeriodicalIF":3.1,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-18DOI: 10.1016/j.ijleo.2025.172349
Wenli Zhang, Kaicheng Wang, Kefan Chen, Yirui Liu, Yi Wang, Junlei Zhi, Hao Chen, Yiping Wang
Image denoising represents a crucial technique for recovering visual information, whereby irrelevant noise is effectively suppressed, thus enhancing the quality and recognition of the image. It has been demonstrated that existing image-denoising algorithms can achieve considerable denoising effects when the noise intensity is known. However, natural images are affected by multiple unknown noise sources during the generation and transmission processes. The unpredictable nature of the noise intensity often results in unsatisfactory image-denoising effects. Therefore, this paper proposes a block-matching three-dimensional cooperative filtering (BM3D) optical image denoising algorithm based on singular value decomposition (SVD) noise estimation. First, the optical image is decomposed by SVD. Then, using the tail of singular values to estimate the noise variance of the optical image. Subsequently, the noise estimated value is employed as prior information for BM3D, facilitating the denoising analysis of the optical image. The final step is to use the PSNR to evaluate the algorithm's effectiveness. Experimental results show that compared with the classical image denoising algorithm, the denoising effect of the algorithm in this paper can better preserve image details, reduce noise residue, and perform better in terms of visual effects and PSNR.
{"title":"BM3D optical image denoising algorithm based on SVD noise estimation","authors":"Wenli Zhang, Kaicheng Wang, Kefan Chen, Yirui Liu, Yi Wang, Junlei Zhi, Hao Chen, Yiping Wang","doi":"10.1016/j.ijleo.2025.172349","DOIUrl":"10.1016/j.ijleo.2025.172349","url":null,"abstract":"<div><div>Image denoising represents a crucial technique for recovering visual information, whereby irrelevant noise is effectively suppressed, thus enhancing the quality and recognition of the image. It has been demonstrated that existing image-denoising algorithms can achieve considerable denoising effects when the noise intensity is known. However, natural images are affected by multiple unknown noise sources during the generation and transmission processes. The unpredictable nature of the noise intensity often results in unsatisfactory image-denoising effects. Therefore, this paper proposes a block-matching three-dimensional cooperative filtering (BM3D) optical image denoising algorithm based on singular value decomposition (SVD) noise estimation. First, the optical image is decomposed by SVD. Then, using the tail of singular values to estimate the noise variance of the optical image. Subsequently, the noise estimated value is employed as prior information for BM3D, facilitating the denoising analysis of the optical image. The final step is to use the PSNR to evaluate the algorithm's effectiveness. Experimental results show that compared with the classical image denoising algorithm, the denoising effect of the algorithm in this paper can better preserve image details, reduce noise residue, and perform better in terms of visual effects and PSNR.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172349"},"PeriodicalIF":3.1,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.ijleo.2025.172345
Yifan Chen , Yuchen Jiang , Jianli Man , Sha Luo , Mingyue Zhang
In order to achieve pose estimation for robotic arms in unstructured grasping scenarios, meeting the demands of unmanned and intelligent industrial production, research has been conducted on the unstructured grasping and pose estimation of robotic arms. Firstly, the scene point cloud was preprocessed, introducing an adaptive statistical filtering algorithm to address the denoising issues encountered in traditional statistical filtering. Subsequently, target extraction was performed using an improved PPF algorithm for point cloud registration. Finally, precise pose estimation was accomplished through ICP registration, and algorithm validation as well as grasping experiments were conducted on both public datasets and data collected in laboratory environments. The experimental results indicate: After conducting grasping experiments in the grasping environment of existing laboratory equipment, it is obtained that the pose recognition accuracy and grasping success rate of our algorithm reached 93. 23 % and 85. 61 %, respectively. The recognition time was 37. 21 seconds, and the total time consumed was 68. 33 seconds, meeting the requirements of the established applications. Therefore, under the rhythm conditions of industrial production, this method ensures the robustness and accuracy requirements of pose estimation, achieving satisfactory results.
{"title":"Improving PPF algorithm for workpiece grasping with adaptive pose estimation","authors":"Yifan Chen , Yuchen Jiang , Jianli Man , Sha Luo , Mingyue Zhang","doi":"10.1016/j.ijleo.2025.172345","DOIUrl":"10.1016/j.ijleo.2025.172345","url":null,"abstract":"<div><div>In order to achieve pose estimation for robotic arms in unstructured grasping scenarios, meeting the demands of unmanned and intelligent industrial production, research has been conducted on the unstructured grasping and pose estimation of robotic arms. Firstly, the scene point cloud was preprocessed, introducing an adaptive statistical filtering algorithm to address the denoising issues encountered in traditional statistical filtering. Subsequently, target extraction was performed using an improved PPF algorithm for point cloud registration. Finally, precise pose estimation was accomplished through ICP registration, and algorithm validation as well as grasping experiments were conducted on both public datasets and data collected in laboratory environments. The experimental results indicate: After conducting grasping experiments in the grasping environment of existing laboratory equipment, it is obtained that the pose recognition accuracy and grasping success rate of our algorithm reached 93. 23 % and 85. 61 %, respectively. The recognition time was 37. 21 seconds, and the total time consumed was 68. 33 seconds, meeting the requirements of the established applications. Therefore, under the rhythm conditions of industrial production, this method ensures the robustness and accuracy requirements of pose estimation, achieving satisfactory results.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172345"},"PeriodicalIF":3.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.ijleo.2025.172342
Veronica Pastor-Villarrubia , Angela Soria-Garcia , Joaquin Andres-Porras , Jesus del Hoyo , Mahmoud H. Elshorbagy , Luis Miguel Sanchez-Brea , Javier Alda
Photon sieves are permeable diffractive optical elements generated by open apertures on a substrate. These elements are well suited for the monitoring of running fluids. Our analysis considers the fabrication constrains of the photon sieve and translate them into values of the optical parameters of the element. When used as focusing elements, or diffractive lenses, the spatial distribution of apertures can be designed to maximize the intensity at the focal plane and the permeability of the device. This is done by defining a weighted merit function. The computation time of this merit function is key when applying different strategies for the design, which often require a very large number of calculations of this merit function. Then, besides using a reliable propagation method, we have included an analytic solution applicable for circular apertures. Also, a geometrical merit function is proposed to simplify and reduce the computation even more. The methods proposed in this contribution are compared in terms of the focused irradiance and permeability parameters, allowing an educated choice adapted to the given case or application. In this contribution we analyze several methods to generate photon sieves in an optimum manner. The resulted spatial distributions resemble the classical Fresnel zone arrangement.
{"title":"Optimum design of permeable diffractive lenses based on photon sieves","authors":"Veronica Pastor-Villarrubia , Angela Soria-Garcia , Joaquin Andres-Porras , Jesus del Hoyo , Mahmoud H. Elshorbagy , Luis Miguel Sanchez-Brea , Javier Alda","doi":"10.1016/j.ijleo.2025.172342","DOIUrl":"10.1016/j.ijleo.2025.172342","url":null,"abstract":"<div><div>Photon sieves are permeable diffractive optical elements generated by open apertures on a substrate. These elements are well suited for the monitoring of running fluids. Our analysis considers the fabrication constrains of the photon sieve and translate them into values of the optical parameters of the element. When used as focusing elements, or diffractive lenses, the spatial distribution of apertures can be designed to maximize the intensity at the focal plane and the permeability of the device. This is done by defining a weighted merit function. The computation time of this merit function is key when applying different strategies for the design, which often require a very large number of calculations of this merit function. Then, besides using a reliable propagation method, we have included an analytic solution applicable for circular apertures. Also, a geometrical merit function is proposed to simplify and reduce the computation even more. The methods proposed in this contribution are compared in terms of the focused irradiance and permeability parameters, allowing an educated choice adapted to the given case or application. In this contribution we analyze several methods to generate photon sieves in an optimum manner. The resulted spatial distributions resemble the classical Fresnel zone arrangement.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172342"},"PeriodicalIF":3.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.ijleo.2025.172343
Khalid Subhi Ahmad , Ahmed Jamal Abdullah Al-Gburi
This research presents the design of a multi-band frequency reconfigurable slot antenna (FRSA) that utilizes graphene in the terahertz (THz) regime. The proposed FRSA supports independent switching across twenty-nine operating bands: 0.518, 0.532, 0.56, 0.59, 0.636, 0.648, 0.66, 0.682, 0.724, 0.752, 0.758, 0.84, 0.938, 0.906, 1.166, 1.252, 1.256, 1.26, 1.304, 1.324, 1.336, 1.344, 1.532, 1.648, 1.70, 1.784, 1.95, 2.01, and 2.064 THz. The design features a rectangular patch with both vertical and longitudinal slots and incorporates seven graphene switches (labeled d1–d7) placed along these slots. These switches enable reconfigurability by controlling the surface conductivity of the graphene. The tunable properties of graphene present significant potential for developing smaller, reconfigurable antennas in THz wireless systems. The proposed FRSA features a compact design with dimensions of 268 µm x 240 µm x 10 µm, or 0.46 λ₀ × 0.41 λ₀ × 0.017 λ₀, where λ₀ represents the wavelength corresponding to the lowest operating frequency of 0.518 THz in free space. The patch structure is mounted on a 10 μm thick substrate made of Rogers RO3003 (with εr = 3 and tanδ = 0.001). The surface conductivity of graphene sheets is adjustable by applying a bias voltage, which influences the chemical potential of the graphene. The FRSA operates in ten states (S1–S10), determined by the ON and OFF positions of the graphene sheets. An analysis of the antenna performance was conducted, examining the reflection coefficient, and gain at various chemical potentials. This switching capability enables secondary users to access unused frequency bands, making the antenna suitable for cognitive radio applications. Furthermore, this technology can be applied in medical settings, as the antenna can assist in identifying skin conditions and cancerous tissues. By switching between different frequencies, it can improve imaging quality and capture various types of data about the body being examined.
{"title":"Graphene-based frequency reconfigurable slot antenna for terahertz applications","authors":"Khalid Subhi Ahmad , Ahmed Jamal Abdullah Al-Gburi","doi":"10.1016/j.ijleo.2025.172343","DOIUrl":"10.1016/j.ijleo.2025.172343","url":null,"abstract":"<div><div>This research presents the design of a multi-band frequency reconfigurable slot antenna (FRSA) that utilizes graphene in the terahertz (THz) regime. The proposed FRSA supports independent switching across twenty-nine operating bands: 0.518, 0.532, 0.56, 0.59, 0.636, 0.648, 0.66, 0.682, 0.724, 0.752, 0.758, 0.84, 0.938, 0.906, 1.166, 1.252, 1.256, 1.26, 1.304, 1.324, 1.336, 1.344, 1.532, 1.648, 1.70, 1.784, 1.95, 2.01, and 2.064 THz. The design features a rectangular patch with both vertical and longitudinal slots and incorporates seven graphene switches (labeled d1–d7) placed along these slots. These switches enable reconfigurability by controlling the surface conductivity of the graphene. The tunable properties of graphene present significant potential for developing smaller, reconfigurable antennas in THz wireless systems. The proposed FRSA features a compact design with dimensions of 268 µm x 240 µm x 10 µm, or 0.46 λ₀ × 0.41 λ₀ × 0.017 λ₀, where λ₀ represents the wavelength corresponding to the lowest operating frequency of 0.518 THz in free space. The patch structure is mounted on a 10 μm thick substrate made of Rogers RO3003 (with <em>ε</em><sub><em>r</em></sub> = 3 and <em>tanδ</em> = 0.001). The surface conductivity of graphene sheets is adjustable by applying a bias voltage, which influences the chemical potential of the graphene. The FRSA operates in ten states (S1–S10), determined by the ON and OFF positions of the graphene sheets. An analysis of the antenna performance was conducted, examining the reflection coefficient, and gain at various chemical potentials. This switching capability enables secondary users to access unused frequency bands, making the antenna suitable for cognitive radio applications. Furthermore, this technology can be applied in medical settings, as the antenna can assist in identifying skin conditions and cancerous tissues. By switching between different frequencies, it can improve imaging quality and capture various types of data about the body being examined.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172343"},"PeriodicalIF":3.1,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-16DOI: 10.1016/j.ijleo.2025.172348
Zhixu Dong , Shu Yang , Mengnan Sun , Jiashun Si , Hao Yi
In this study, a method of calculating the optimal filter bandwidth based on the watermark fringes of simulation interference was proposed to maintain the optimal performance of a spatially modulated full-polarisation imaging system in different target scenes, offering some theoretical guidance for the type selection of the imaging lens for the system. The two-dimensional sine function of the watermark fringes of simulation interference was superimposed on the intensity image, and a full-polarisation image was obtained by demodulating the simulation interferogram using the fast Fourier transform and the frequency-domain low-pass-filtering algorithm. Then, the polarisation image with the highest structural similarity to the intensity image was solved, and a method of calculating the optimal filter bandwidth based on the improved elitist clonal selection algorithm (ECSA) was presented. Next, the optimal focal length of the imaging lens was calculated in combination with the image resolutions, incident light wavelengths, and Savart polariser single-beam offsets selected in different target scenes, to complete the theoretical type selection. The experimental results showed that the spatially modulated full-polarisation imaging system constructed based on the optimal filter bandwidth had a good performance; and that, compared with empirical type selection, the proposed type selection based on the optimal filter bandwidth increased the spectral inversion area by 4.2 times and the image structural similarity by 71 %, significantly improving the polarisation imaging quality of the system.
{"title":"A method of optimising the filter bandwidth of a spatially modulated full-polarisation imaging system","authors":"Zhixu Dong , Shu Yang , Mengnan Sun , Jiashun Si , Hao Yi","doi":"10.1016/j.ijleo.2025.172348","DOIUrl":"10.1016/j.ijleo.2025.172348","url":null,"abstract":"<div><div>In this study, a method of calculating the optimal filter bandwidth based on the watermark fringes of simulation interference was proposed to maintain the optimal performance of a spatially modulated full-polarisation imaging system in different target scenes, offering some theoretical guidance for the type selection of the imaging lens for the system. The two-dimensional sine function of the watermark fringes of simulation interference was superimposed on the intensity image, and a full-polarisation image was obtained by demodulating the simulation interferogram using the fast Fourier transform and the frequency-domain low-pass-filtering algorithm. Then, the polarisation image with the highest structural similarity to the intensity image was solved, and a method of calculating the optimal filter bandwidth based on the improved elitist clonal selection algorithm (ECSA) was presented. Next, the optimal focal length of the imaging lens was calculated in combination with the image resolutions, incident light wavelengths, and Savart polariser single-beam offsets selected in different target scenes, to complete the theoretical type selection. The experimental results showed that the spatially modulated full-polarisation imaging system constructed based on the optimal filter bandwidth had a good performance; and that, compared with empirical type selection, the proposed type selection based on the optimal filter bandwidth increased the spectral inversion area by 4.2 times and the image structural similarity by 71 %, significantly improving the polarisation imaging quality of the system.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172348"},"PeriodicalIF":3.1,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-15DOI: 10.1016/j.ijleo.2025.172362
Faisal Munir , Iqbal Hussain , Muhammad Usman , Usman Javed , Muhammad Kashif Majeed , Faisal Nadeem , Muhammad Qasim Khan , Huanrong Fan , Yanpeng Zhang
We report the competition relationship between natural non-Hermitian linear and circular polarization dressings in Eu3+: BiPO4 and Eu3+: NaYF4. We depict that, compare to narrowband excitation (one switch from spectral peak to spectral dip), three dressings lead to the linear or circular polarization signal transition from enhancement peak to suppression dip and to enhancement peak for Eu3+: NaYF4 at broadband excitation due to high decay rate. The linear AT dip is accompanied by two times quantization switches (destructive to constructive, constructive to destructive), while circular AT splitting exhibits one time switch (destructive to constructive quantization) in Eu3+: BiPO4 for narrowband excitation. However, the fluorescence (FL) and multi-Fano of spontaneous four wave mixing (SFWM) shows two circular polarization dressings (two strong dips), which are stronger than linear (one strong dip) at fixing detector. However, the linear and polarization dressing dips are strong due to weak constructive quantization, while strong circular polarization dressing dip comes from destructive quantization at different detectors. Notably, the linear-circular quantization difference results from Zeeman-like effect of CF and selected linear-circular dressing. These results infer a polarizer device that exhibit linear dressing seven times larger than circular dressing at weak quantization output port.
我们报告了 Eu3+: BiPO4 和 Eu3+：NaYF4。我们描绘了与窄带激发（从光谱峰值到光谱凹陷的一次转换）相比，三种敷料会导致 Eu3+: BiPO4 和 Eu3+: NaYF4 的线性或圆极化信号从增强峰值过渡到抑制凹陷，再从抑制凹陷过渡到增强峰值：在宽带激发下，NaYF4 由于衰减率高而出现增强峰。在窄带激发下，Eu3+：BiPO4 的线性 AT 凹陷伴随着两次量子化转换（破坏性量子化转换为建设性量子化，建设性量子化转换为破坏性量子化），而圆形 AT 分裂则表现出一次量子化转换（破坏性量子化转换为建设性量子化）。然而，自发四波混合（SFWM）的荧光（FL）和多法诺显示出两个圆形极化修饰（两个强凹陷），在固定探测器上比线性（一个强凹陷）强。然而，线性和偏振敷料的强倾角是由于弱构造量子化造成的，而圆偏振敷料的强倾角则来自不同探测器上的破坏性量子化。值得注意的是，线性和圆形量子化差异来自于 CF 的泽曼类效应和选定的线性-圆形偏振片。这些结果推断出，在弱量子化输出端口，偏振器装置的线性修整比圆形修整大七倍。
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Pub Date : 2025-04-11DOI: 10.1016/j.ijleo.2025.172333
Yi-Chen Lee , Chieh-Ming Wu , Pei-Ching Wei , Jen-Feng Hsu , Yu-Chien Lou , Vincent K.S. Hsiao , Ja-Hon Lin , Dong-Sing Wuu
This study presents an approach to synthesize Ag-TiO2 nanocomposites (NCPs) with enhanced nonlinear optical (NLO) properties using laser fragmentation in liquid (LFL). We employed 30 nm Ag nanoparticles (NPs) and 5 nm TiO2 NPs as precursors, utilizing different concentration ratios in aqueous solution. The LFL technique, using a Nd:YAG laser (532 nm, 15 ns pulse duration), enabled direct preparation of Ag-TiO2 NCPs. The morphology, structure, and optical properties of the synthesized NCPs were characterized using TEM, XRD, and UV–visible spectroscopy. NLO properties were investigated using the Z-scan technique with a femtosecond Ti:Sapphire laser (800 nm, 129 fs pulse duration). Results revealed enhancement in nonlinear absorption in Ag-TiO2 NCPs compared to pure Ag NPs. The nonlinear absorption coefficient (β) and nonlinear refractive index (n2) were determined experimentally using ZnSe as standard sample. The β value was found to be 1.27 cm/GW. The n2 and the third-order nonlinear susceptibility (χ3) were on the order of 10−14 esu. We propose that TiO2 NPs enhance the local electric field of Ag NPs and promote charge transfer, significantly improving the NLO response of the composite material. This study provides new insights into the controlled preparation and performance optimization of Ag-TiO2 NCPs, offering potential applications in NLO applications.
{"title":"Characterization and nonlinear optical property of Ag-TiO2 nanocomposites fabricated by laser fragmentation in liquid","authors":"Yi-Chen Lee , Chieh-Ming Wu , Pei-Ching Wei , Jen-Feng Hsu , Yu-Chien Lou , Vincent K.S. Hsiao , Ja-Hon Lin , Dong-Sing Wuu","doi":"10.1016/j.ijleo.2025.172333","DOIUrl":"10.1016/j.ijleo.2025.172333","url":null,"abstract":"<div><div>This study presents an approach to synthesize Ag-TiO<sub>2</sub> nanocomposites (NCPs) with enhanced nonlinear optical (NLO) properties using laser fragmentation in liquid (LFL). We employed 30 nm Ag nanoparticles (NPs) and 5 nm TiO<sub>2</sub> NPs as precursors, utilizing different concentration ratios in aqueous solution. The LFL technique, using a Nd:YAG laser (532 nm, 15 ns pulse duration), enabled direct preparation of Ag-TiO<sub>2</sub> NCPs. The morphology, structure, and optical properties of the synthesized NCPs were characterized using TEM, XRD, and UV–visible spectroscopy. NLO properties were investigated using the Z-scan technique with a femtosecond Ti:Sapphire laser (800 nm, 129 fs pulse duration). Results revealed enhancement in nonlinear absorption in Ag-TiO<sub>2</sub> NCPs compared to pure Ag NPs. The nonlinear absorption coefficient (β) and nonlinear refractive index (n<sub>2</sub>) were determined experimentally using ZnSe as standard sample. The β value was found to be 1.27 cm/GW. The n<sub>2</sub> and the third-order nonlinear susceptibility (χ<sup>3</sup>) were on the order of 10<sup>−14</sup> esu. We propose that TiO<sub>2</sub> NPs enhance the local electric field of Ag NPs and promote charge transfer, significantly improving the NLO response of the composite material. This study provides new insights into the controlled preparation and performance optimization of Ag-TiO<sub>2</sub> NCPs, offering potential applications in NLO applications.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"330 ","pages":"Article 172333"},"PeriodicalIF":3.1,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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