Pub Date : 2025-02-15DOI: 10.1016/j.ijleo.2025.172258
D. Zárate-Villegas, Ivan Moreno
Designing lenses for wavelengths below 121 nm is challenging due to the strong absorption of optical materials. This study introduces a metalens composed of ring-shaped silica nano-elements that efficiently focus extreme ultraviolet (EUV) radiation. Each ring features an air or vacuum core () surrounded by silica with a refractive index , optimized for EUV operation. Finite-difference time-domain (FDTD) simulations demonstrate a phase coverage of 1.85 , high EUV transmission, and an optical efficiency of 83.6%. These results represent a significant advancement over existing EUV metalenses, and underscore the potential of this design for compact and efficient EUV optical systems.
{"title":"Extreme UV metalens consisting of ring meta-atoms","authors":"D. Zárate-Villegas, Ivan Moreno","doi":"10.1016/j.ijleo.2025.172258","DOIUrl":"10.1016/j.ijleo.2025.172258","url":null,"abstract":"<div><div>Designing lenses for wavelengths below 121 nm is challenging due to the strong absorption of optical materials. This study introduces a metalens composed of ring-shaped silica nano-elements that efficiently focus extreme ultraviolet (EUV) radiation. Each ring features an air or vacuum core (<span><math><mrow><mi>n</mi><mo>=</mo><mn>1</mn></mrow></math></span>) surrounded by silica with a refractive index <span><math><mrow><mi>n</mi><mo><</mo><mn>1</mn></mrow></math></span>, optimized for EUV operation. Finite-difference time-domain (FDTD) simulations demonstrate a phase coverage of 1.85 <span><math><mi>π</mi></math></span>, high EUV transmission, and an optical efficiency of 83.6%. These results represent a significant advancement over existing EUV metalenses, and underscore the potential of this design for compact and efficient EUV optical systems.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172258"},"PeriodicalIF":3.1,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437083","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 : 2025-02-14DOI: 10.1016/j.ijleo.2025.172260
Alireza Zarei , Srikanth Pilla
When a laser pulse impinges on a composite material, a portion of the light is absorbed by the matrix, while the remainder is absorbed by the embedded fibers. Conventional models overlook the substantial differences in optical properties between these two constituents. This paper, however, introduces a novel analytical model for laser light absorption in fiber-reinforced composite materials. This macroscopic model incorporates distinct optical absorptivity for both the matrix and embedded fibers, offering adaptability to various scenarios without introducing additional computational cost to simulations. The dynamic thermal expansion and elastic wave generation inside the material is considered to study the effects of the presented model on the generated waves. Investigations are conducted on a Carbon Fiber Reinforced Plastic (CFRP) plate with variable epoxy layer thickness using Nd:YAG and mid-IR lasers. Results demonstrate a significant enhancement in temperature distribution within the material, elucidating experimental observations previously unexplained by conventional models. Under consistent laser energy, pulse duration, and beam radius, the Nd:YAG laser induces notably higher temperatures in the CFRP-epoxy interface compared to the mid-IR laser. Furthermore, thicker epoxy layers result in lower temperatures and higher displacement amplitudes, aligning with the desirable characteristics for laser ultrasonic testing applications.
{"title":"A novel laser light absorption model for composite materials in the context of laser ultrasonic testing","authors":"Alireza Zarei , Srikanth Pilla","doi":"10.1016/j.ijleo.2025.172260","DOIUrl":"10.1016/j.ijleo.2025.172260","url":null,"abstract":"<div><div>When a laser pulse impinges on a composite material, a portion of the light is absorbed by the matrix, while the remainder is absorbed by the embedded fibers. Conventional models overlook the substantial differences in optical properties between these two constituents. This paper, however, introduces a novel analytical model for laser light absorption in fiber-reinforced composite materials. This macroscopic model incorporates distinct optical absorptivity for both the matrix and embedded fibers, offering adaptability to various scenarios without introducing additional computational cost to simulations. The dynamic thermal expansion and elastic wave generation inside the material is considered to study the effects of the presented model on the generated waves. Investigations are conducted on a Carbon Fiber Reinforced Plastic (CFRP) plate with variable epoxy layer thickness using Nd:YAG and mid-IR lasers. Results demonstrate a significant enhancement in temperature distribution within the material, elucidating experimental observations previously unexplained by conventional models. Under consistent laser energy, pulse duration, and beam radius, the Nd:YAG laser induces notably higher temperatures in the CFRP-epoxy interface compared to the mid-IR laser. Furthermore, thicker epoxy layers result in lower temperatures and higher displacement amplitudes, aligning with the desirable characteristics for laser ultrasonic testing applications.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172260"},"PeriodicalIF":3.1,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437127","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 : 2025-02-13DOI: 10.1016/j.ijleo.2025.172263
Salah Abdulrhmann
This article investigates the effects of strong optical feedback on the operational states and relative intensity noise fluctuations of long external cavity semiconductor lasers. Using modified rate equations, the findings show that the pulsation amplitude increases significantly, and the time to reach steady-state operation decreases when noise sources are included. Under strong optical feedback, the laser exhibits pulsating behavior, with relative intensity noise reduced to quantum noise level at high injection currents. In chaotic conditions, two peaks appear at the external and relaxation frequencies, indicating instability due to two threshold conditions related to the laser and external cavity. Consequently, the low-frequency relative intensity noise is elevated above quantum noise levels. Increasing the optical feedback and enhancing the injection current are essential for stable, low-noise pulsating laser operation.
{"title":"Operational states and intensity noise characteristics of time-delayed semiconductor lasers subject to strong optical feedback","authors":"Salah Abdulrhmann","doi":"10.1016/j.ijleo.2025.172263","DOIUrl":"10.1016/j.ijleo.2025.172263","url":null,"abstract":"<div><div>This article investigates the effects of strong optical feedback on the operational states and relative intensity noise fluctuations of long external cavity semiconductor lasers. Using modified rate equations, the findings show that the pulsation amplitude increases significantly, and the time to reach steady-state operation decreases when noise sources are included. Under strong optical feedback, the laser exhibits pulsating behavior, with relative intensity noise reduced to quantum noise level at high injection currents. In chaotic conditions, two peaks appear at the external and relaxation frequencies, indicating instability due to two threshold conditions related to the laser and external cavity. Consequently, the low-frequency relative intensity noise is elevated above quantum noise levels. Increasing the optical feedback and enhancing the injection current are essential for stable, low-noise pulsating laser operation.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172263"},"PeriodicalIF":3.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420166","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}
This study reports the superiority of superlattice Si/SiC Avalanche Photodiode (APD) over its flat profile Si and SiCcounterparts. A large signal quantum corrected drift-diffusion (LSQC-DD) model is developed and used for the electro optical characteristic studies of the devices for application in UV detection. The effect of charge bump in the optimized doping profile near the metallurgical junction of the Device Under Test (DUT) is studied and reported for the first time in detailed. These results in the betterment of quantum efficiency compared to its flat profile counterpart (95 % vs.91 %). This study also reports the suitability of 3 × 3 array based APD photo sensors in terms of photo responsivity and quantum efficiency. Significant Noise reduction in case of Si/SiC superlattice devices would open its application possibility as low noise single photon detector. The validity of the indigenously developed simulator is established through experimental verification. Fabrication feasibility of the new class of superlattice APD is presented. To the best of authors' knowledge this is the first report on superlattice Si/SiC APD as single photon UV detector.
{"title":"Superlattice Si/SiC APD with improved photo-sensitivity and stability: Application as low noise single photon detector","authors":"Debraj Modak , Saunak Bhattacharya , Karabi Ganguly , Indranath Sarkar , Moumita Mukherjee , Abhijit Kundu","doi":"10.1016/j.ijleo.2025.172256","DOIUrl":"10.1016/j.ijleo.2025.172256","url":null,"abstract":"<div><div>This study reports the superiority of superlattice Si/SiC Avalanche Photodiode (APD) over its flat profile Si and SiCcounterparts. A large signal quantum corrected drift-diffusion (LSQC-DD) model is developed and used for the electro optical characteristic studies of the devices for application in UV detection. The effect of charge bump in the optimized doping profile near the metallurgical junction of the Device Under Test (DUT) is studied and reported for the first time in detailed. These results in the betterment of quantum efficiency compared to its flat profile counterpart (95 % vs.91 %). This study also reports the suitability of 3 × 3 array based APD photo sensors in terms of photo responsivity and quantum efficiency. Significant Noise reduction in case of Si/SiC superlattice devices would open its application possibility as low noise single photon detector. The validity of the indigenously developed simulator is established through experimental verification. Fabrication feasibility of the new class of superlattice APD is presented. To the best of authors' knowledge this is the first report on superlattice Si/SiC APD as single photon UV detector.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172256"},"PeriodicalIF":3.1,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420165","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 : 2025-02-12DOI: 10.1016/j.ijleo.2025.172261
Beier Liang , Jingxuan Guo , Shu Liu , Cheng Zong , Yong Cheng , Jing Chen
The near-field information of optical structures is vital for understanding the behavior of materials at minuscule scales and innovating new technologies. However, the acquisition of near-field information involves substantial data, and traditional numerical simulations are constrained by computational resources and time. To solve this problem, we propose a method that integrates the multimodal model Stable Diffusion with the deep subwavelength spherical hyperbolic metamaterial cavity, to establish the mapping relationship between the electric field distribution and the cavity parameters. After training, the model can accurately and quickly predict the electric field map at preset structural information, and it is highly consistent with simulated results. Additionally, we use the Contrastive Language-Image Pretraining (CLIP) algorithm to retrieve the structural information based on the given electric field distribution, for the inverse design of the metamaterial cavity. The results demonstrate that our method provides a fast and accurate way to obtain near-field information and also can accelerate the on-demand design of optical metamaterials and other structures, with promising implications for real-world applications.
{"title":"Near-field distribution prediction and inverse design of spherical hyperbolic metamaterial cavity using multimodal models","authors":"Beier Liang , Jingxuan Guo , Shu Liu , Cheng Zong , Yong Cheng , Jing Chen","doi":"10.1016/j.ijleo.2025.172261","DOIUrl":"10.1016/j.ijleo.2025.172261","url":null,"abstract":"<div><div>The near-field information of optical structures is vital for understanding the behavior of materials at minuscule scales and innovating new technologies. However, the acquisition of near-field information involves substantial data, and traditional numerical simulations are constrained by computational resources and time. To solve this problem, we propose a method that integrates the multimodal model Stable Diffusion with the deep subwavelength spherical hyperbolic metamaterial cavity, to establish the mapping relationship between the electric field distribution and the cavity parameters. After training, the model can accurately and quickly predict the electric field map at preset structural information, and it is highly consistent with simulated results. Additionally, we use the Contrastive Language-Image Pretraining (CLIP) algorithm to retrieve the structural information based on the given electric field distribution, for the inverse design of the metamaterial cavity. The results demonstrate that our method provides a fast and accurate way to obtain near-field information and also can accelerate the on-demand design of optical metamaterials and other structures, with promising implications for real-world applications.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172261"},"PeriodicalIF":3.1,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437128","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}
Integrating deep learning techniques into optical imaging systems has ramped up the procedures of biomedical investigation and allowed an unprecedented number of ways to acquiring experimental data. This study attempts to apply a Deep-Q Network (DQN)-based reinforcement learning technique to automatically locate the cross section of the ventricular chamber of zebrafish larvae in a light-sheet fluorescence microscopy. Experimentally, a total of 920 cardiac images of zebrafish larvae were acquired, pre-formatted and manually annotated to ensure the maximal utilization and precise interpretation of the data. Subsequently, a YOLOv5 algorithm was used for image recognition, which were implemented as the state of the custom-created environment in reinforcement learning. A reward score can then be derived through the controlling of the motorized moving platform and used to train a positioning model based on the Deep-Q Network (DQN). This reinforcement learning model not only can learn and improve from the past experience, but also optimize its dynamic behavior on the basis of the designs of a reward formula and an architecture of the learning strategy. Such reward feedback system dynamically directs the sample-loaded moving platform toward an image cross-section of larval zebrafish's cardiac chamber with the best contrast and clarity. The training results indicate that the object-searching DQN model is capable of precisely allocating the optimal cross-section of the ventricular chamber, can achieve the task with a success rate of 96 % in 600 training episodes, and has the advantages of efficiency and precision when compared with the Greedy method, a random strategy and a modified reward formula.
{"title":"In vivo localization of larval zebrafish’s cardiac chambers in lightsheet fluorescence microscopy using a customized reward function module-incorporated Deep-Q-Network model for reinforcement learning","authors":"Hao-Hsuan Chung , Jen-Jee Chen , Huai-Jen Tsai , Po-Sheng Hu","doi":"10.1016/j.ijleo.2025.172255","DOIUrl":"10.1016/j.ijleo.2025.172255","url":null,"abstract":"<div><div>Integrating deep learning techniques into optical imaging systems has ramped up the procedures of biomedical investigation and allowed an unprecedented number of ways to acquiring experimental data. This study attempts to apply a Deep-Q Network (DQN)-based reinforcement learning technique to automatically locate the cross section of the ventricular chamber of zebrafish larvae in a light-sheet fluorescence microscopy. Experimentally, a total of 920 cardiac images of zebrafish larvae were acquired, pre-formatted and manually annotated to ensure the maximal utilization and precise interpretation of the data. Subsequently, a YOLOv5 algorithm was used for image recognition, which were implemented as the state of the custom-created environment in reinforcement learning. A reward score can then be derived through the controlling of the motorized moving platform and used to train a positioning model based on the Deep-Q Network (DQN). This reinforcement learning model not only can learn and improve from the past experience, but also optimize its dynamic behavior on the basis of the designs of a reward formula and an architecture of the learning strategy. Such reward feedback system dynamically directs the sample-loaded moving platform toward an image cross-section of larval zebrafish's cardiac chamber with the best contrast and clarity. The training results indicate that the object-searching DQN model is capable of precisely allocating the optimal cross-section of the ventricular chamber, can achieve the task with a success rate of 96 % in 600 training episodes, and has the advantages of efficiency and precision when compared with the Greedy method, a random strategy and a modified reward formula.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"326 ","pages":"Article 172255"},"PeriodicalIF":3.1,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395643","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 : 2025-02-07DOI: 10.1016/j.ijleo.2025.172257
Pei Ruan, Yiping He, Qian Yang, Daobin Luo
To investigate the backscattering characteristics in the solar spectrum, the Discrete Dipole Approximation (DDA) method was employed to simulate backscattering efficiency. For Ge-Au Janus nanoparticles (JNPs), the influence of particle size, environmental medium, and the metal volume ratio on the backscattering efficiency were investigated in this work. It was found that the backscattering peak of Ge-Au-JNPs undergoes a redshift with increasing environmental medium, accompanied by a significant enhancement in peak intensity. Additionally, by adjusting the volume ratio of Ge-Au metal, it was found that the peak of backward scattering efficiency reached a maximum at 652 nm for an ambient refractive index of m= 1.33 and a ratio of 1:4. This indicates that the backscattering properties of Ge-Au Janus nanoparticles are tunable by the surrounding refractive index and the component ratio of the Janus nanoparticles, providing an optimization method for applications such as solar energy harvesting and optical sensing.
{"title":"Backscattering properties of trigonal Ge-Au Janus nanoparticles with different ambient refractive indices in the visible solar spectrum","authors":"Pei Ruan, Yiping He, Qian Yang, Daobin Luo","doi":"10.1016/j.ijleo.2025.172257","DOIUrl":"10.1016/j.ijleo.2025.172257","url":null,"abstract":"<div><div>To investigate the backscattering characteristics in the solar spectrum, the Discrete Dipole Approximation (DDA) method was employed to simulate backscattering efficiency. For Ge-Au Janus nanoparticles (JNPs), the influence of particle size, environmental medium, and the metal volume ratio on the backscattering efficiency were investigated in this work. It was found that the backscattering peak of Ge-Au-JNPs undergoes a redshift with increasing environmental medium, accompanied by a significant enhancement in peak intensity. Additionally, by adjusting the volume ratio of Ge-Au metal, it was found that the peak of backward scattering efficiency reached a maximum at 652 nm for an ambient refractive index of m= 1.33 and a ratio of 1:4. This indicates that the backscattering properties of Ge-Au Janus nanoparticles are tunable by the surrounding refractive index and the component ratio of the Janus nanoparticles, providing an optimization method for applications such as solar energy harvesting and optical sensing.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"325 ","pages":"Article 172257"},"PeriodicalIF":3.1,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403097","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 : 2025-02-05DOI: 10.1016/j.ijleo.2025.172248
Radhika Rathod , H. Bhuva , V.J. Pandya , Zala Maulik , Hepi Ladani , H.O. Jethva
The effect of manganese ion on the structural, linear and nonlinear optical characteristics of the magnesium sulphate heptahydrate crystals was investigated. The pure and manganese ion doped magnesium sulphate heptahydrate crystals were grown using the solvent evaporation technique at room temperature. The structural analysis suggested change in the structure symmetry from orthorhombic to monoclinic crystal system by manganese ion doping. The optical constants and parameters were evaluated using Shimadzu UV-1700 Phamaspec UV spectrometer and measurements were performed at a wavelength of 200–800 nm. The obtained UV chromatograph was recorded by Shimadzu UV prob 2.6 software. The optical bandgap showed direct transitions which decreased by manganese ion doping, while steepness parameter for direct transitions showed a contrary attitude. Linear and nonlinear refractive index, extinction coefficient, optical density, optical conductivity, optical susceptibility, optical dielectric properties, inter-band transition strength, energy loss functions and nonlinear susceptibility were found to be greatly influenced by manganese ion doping and were also dependent on the incident wave energy. The optical study of the grown crystals was further extended using various optical dispersion models like Wemple-DiDomenico single oscillator model, Sellmeier dispersion relation and Drude model. The effect of Mn doping on the dispersion of second order refractive index, two photon absorption coefficient, Figure of Merit (FOM) and third order optical susceptibility was studied in a wide range of photon wavelength from 250 to 700 nm.
{"title":"Effect of manganese ion on structural, linear and nonlinear optical properties of magnesium sulphate heptahydrate crystals","authors":"Radhika Rathod , H. Bhuva , V.J. Pandya , Zala Maulik , Hepi Ladani , H.O. Jethva","doi":"10.1016/j.ijleo.2025.172248","DOIUrl":"10.1016/j.ijleo.2025.172248","url":null,"abstract":"<div><div>The effect of manganese ion on the structural, linear and nonlinear optical characteristics of the magnesium sulphate heptahydrate crystals was investigated. The pure and manganese ion doped magnesium sulphate heptahydrate crystals were grown using the solvent evaporation technique at room temperature. The structural analysis suggested change in the structure symmetry from orthorhombic to monoclinic crystal system by manganese ion doping. The optical constants and parameters were evaluated using Shimadzu UV-1700 Phamaspec UV spectrometer and measurements were performed at a wavelength of 200–800 nm. The obtained UV chromatograph was recorded by Shimadzu UV prob 2.6 software. The optical bandgap showed direct transitions which decreased by manganese ion doping, while steepness parameter for direct transitions showed a contrary attitude. Linear and nonlinear refractive index, extinction coefficient, optical density, optical conductivity, optical susceptibility, optical dielectric properties, inter-band transition strength, energy loss functions and nonlinear susceptibility were found to be greatly influenced by manganese ion doping and were also dependent on the incident wave energy. The optical study of the grown crystals was further extended using various optical dispersion models like Wemple-DiDomenico single oscillator model, Sellmeier dispersion relation and Drude model. The effect of Mn doping on the dispersion of second order refractive index, two photon absorption coefficient, Figure of Merit (FOM) and third order optical susceptibility was studied in a wide range of photon wavelength from 250 to 700 nm.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"325 ","pages":"Article 172248"},"PeriodicalIF":3.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350283","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 : 2025-02-04DOI: 10.1016/j.ijleo.2025.172247
Rajat Nagpal , Cristian Lupan , Artur Buzdugan , Vladislav Ghenea , Oleg Lupan
ZnO: Eu films have been functionalized with Pd nanoparticles of sizes (5–15 nm) synthesized by a chemical solution approach. Morphological and optical characterizations were carried out using SEM and transmission spectroscopy. The effects of Pd functionalization on the ZnO: Eu columnar microstructures have been investigated by analysing the photo response, photoresponsivity, external quantum efficiency (EQE), detectivity, and carrier dynamics rate. The Pd functionalized ZnO: Eu films (Pd40/ZnO: Eu) show a higher photo response (∼33), about three times higher compared to bare ZnO: Eu films (∼12.4) at 100 ℃. This can be explained by photocarrier transfer from the ZnO conduction band to the Fermi level of PdO and electron trapping on the sensing surface due to oxygen adsorption. A remarkable EQE and detectivity were found for both sample sets, Pd40/ZnO: Eu (∼930 %, ∼2˟1013 Jones) and ZnO: Eu (∼2030 %, ∼1.71˟1013 Jones). High UV–visible rejection ratio (R280 nm/R443 nm) of ∼82 is found, indicating good spectral selectivity. The effect of irradiance on photoresponsivity and recovery time has also been investigated and shows that increasing irradiance leads to an increase in electron-hole pair generation at a faster rate, contributing to higher photoresponsivity and faster recovery. Pd-functionalization results in higher gas sensing response of ∼15 and improved selectivity to 100 ppm hydrogen at lower operating temperatures for Pd40/ZnO: Eu films. The proposed columnar microstructures may enable advanced photodetector applications at relatively low bias voltage (∼50 mV). In this work, the importance towards Pd functionalization for H2 gas sensing and UV detection is presented.
{"title":"Effect of Pd functionalization on optical and hydrogen sensing properties of ZnO: Eu films","authors":"Rajat Nagpal , Cristian Lupan , Artur Buzdugan , Vladislav Ghenea , Oleg Lupan","doi":"10.1016/j.ijleo.2025.172247","DOIUrl":"10.1016/j.ijleo.2025.172247","url":null,"abstract":"<div><div>ZnO: Eu films have been functionalized with Pd nanoparticles of sizes (5–15 nm) synthesized by a chemical solution approach. Morphological and optical characterizations were carried out using SEM and transmission spectroscopy. The effects of Pd functionalization on the ZnO: Eu columnar microstructures have been investigated by analysing the photo response, photoresponsivity, external quantum efficiency (EQE), detectivity, and carrier dynamics rate. The Pd functionalized ZnO: Eu films (Pd40/ZnO: Eu) show a higher photo response (∼33), about three times higher compared to bare ZnO: Eu films (∼12.4) at 100 ℃. This can be explained by photocarrier transfer from the ZnO conduction band to the Fermi level of PdO and electron trapping on the sensing surface due to oxygen adsorption. A remarkable EQE and detectivity were found for both sample sets, Pd40/ZnO: Eu (∼930 %, ∼2˟10<sup>13</sup> Jones) and ZnO: Eu (∼2030 %, ∼1.71˟10<sup>13</sup> Jones). High UV–visible rejection ratio (R<sub>280 nm</sub>/R<sub>443 nm</sub>) of ∼82 is found, indicating good spectral selectivity. The effect of irradiance on photoresponsivity and recovery time has also been investigated and shows that increasing irradiance leads to an increase in electron-hole pair generation at a faster rate, contributing to higher photoresponsivity and faster recovery. Pd-functionalization results in higher gas sensing response of ∼15 and improved selectivity to 100 ppm hydrogen at lower operating temperatures for Pd40/ZnO: Eu films. The proposed columnar microstructures may enable advanced photodetector applications at relatively low bias voltage (∼50 mV). In this work, the importance towards Pd functionalization for H<sub>2</sub> gas sensing and UV detection is presented.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"325 ","pages":"Article 172247"},"PeriodicalIF":3.1,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1016/j.ijleo.2025.172244
M.Kh. Ismail , T.M. El-Shahat , N. Metwally , A.-S.F. Obada
The capability of the Anti-Jaynes–Cummings model (AJCM) to generate quantum correlations between finite- and infinite-dimensional subsystems has been investigated. This concept is demonstrated by considering an atom with varying dimensionalities interacting with a cavity mode prepared in different initial states. The findings show that the entangling power of the AJCM, and consequently the generated entanglement, can be maximized when a cavity mode prepared in coherent or squeezed vacuum states interacts locally with a three- or four-dimensional atom. Additionally, increasing the mean photon number inside the cavity enhances both the entangling power and the degree of entanglement between the subsystems. A harmonious relationship is observed between the entangling power and the entanglement measure, with sudden, gradual, and constant behaviors predicted at the same interaction time.
{"title":"Entangling power for Anti-Jaynes–Cummings Model","authors":"M.Kh. Ismail , T.M. El-Shahat , N. Metwally , A.-S.F. Obada","doi":"10.1016/j.ijleo.2025.172244","DOIUrl":"10.1016/j.ijleo.2025.172244","url":null,"abstract":"<div><div>The capability of the Anti-Jaynes–Cummings model (AJCM) to generate quantum correlations between finite- and infinite-dimensional subsystems has been investigated. This concept is demonstrated by considering an atom with varying dimensionalities interacting with a cavity mode prepared in different initial states. The findings show that the entangling power of the AJCM, and consequently the generated entanglement, can be maximized when a cavity mode prepared in coherent or squeezed vacuum states interacts locally with a three- or four-dimensional atom. Additionally, increasing the mean photon number inside the cavity enhances both the entangling power and the degree of entanglement between the subsystems. A harmonious relationship is observed between the entangling power and the entanglement measure, with sudden, gradual, and constant behaviors predicted at the same interaction time.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"325 ","pages":"Article 172244"},"PeriodicalIF":3.1,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143265499","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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