Micro-LED undoubtedly stands out as a highly anticipated technology when it comes to the innovation of future display technologies. Micro-LED technology surpasses traditional display technologies regarding color representation, energy efficiency, and flexibility by individually assembling tiny light-emitting diodes on a substrate. Micro-LED technology, a further evolution of LED, is considered the most promising next-generation display technology due to its outstanding brightness, high contrast ratio, and extremely high pixel density. The application of laser technology in Micro-LED displays is increasingly becoming a focus of research and industry. As a highly integrated light source, lasers offer unique advantages in Micro-LED applications, including high-energy density processing, non-contact processing, precise microstructure processing and sculpting capability, efficient packaging, and improved device quality and reliability. These advantages provide a distinctive edge in achieving high-precision manufacturing and assembly of Micro-LED chips. Laser epitaxy substrate technology utilizes laser heating and material deposition to grow Micro-LED chips on a substrate. Laser etching technology achieves precise control of lasers to enable microstructure processing and sculpting of Micro-LED devices. Laser lift-off technology utilizes laser-induced decomposition of GaN to peel off the underlying material, allowing for the separation of Micro-LEDs. Laser-based massive transfer technology uses the energy of lasers to swiftly and accurately transfer Micro-LEDs from the substrate to the target substrate, enabling rapid device transfer. Lastly, laser repair technology is employed for the detection and repair of potential defects in Micro-LEDs, enhancing device quality and reliability. By utilizing lasers, we can expect to achieve higher production efficiency, more precise device manufacturing, and superior optoelectronic performance in the field of Micro-LED, thereby presenting broader prospects for future display technology and lighting applications. These laser technologies provide new solutions for Micro-LED devices’ high-precision and high-efficiency production.
{"title":"Recent progress of laser processing technology in micro-LED display manufacturing: A review","authors":"Lingxiao Song, Xuechao Yong, Peilei Zhang, Shijie Song, Kefan Chen, Hua Yan, Tianzhu Sun, Qinghua Lu, Haichuan Shi, Yu Chen, Yuze Huang","doi":"10.1016/j.optlastec.2024.111710","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111710","url":null,"abstract":"Micro-LED undoubtedly stands out as a highly anticipated technology when it comes to the innovation of future display technologies. Micro-LED technology surpasses traditional display technologies regarding color representation, energy efficiency, and flexibility by individually assembling tiny light-emitting diodes on a substrate. Micro-LED technology, a further evolution of LED, is considered the most promising next-generation display technology due to its outstanding brightness, high contrast ratio, and extremely high pixel density. The application of laser technology in Micro-LED displays is increasingly becoming a focus of research and industry. As a highly integrated light source, lasers offer unique advantages in Micro-LED applications, including high-energy density processing, non-contact processing, precise microstructure processing and sculpting capability, efficient packaging, and improved device quality and reliability. These advantages provide a distinctive edge in achieving high-precision manufacturing and assembly of Micro-LED chips. Laser epitaxy substrate technology utilizes laser heating and material deposition to grow Micro-LED chips on a substrate. Laser etching technology achieves precise control of lasers to enable microstructure processing and sculpting of Micro-LED devices. Laser lift-off technology utilizes laser-induced decomposition of GaN to peel off the underlying material, allowing for the separation of Micro-LEDs. Laser-based massive transfer technology uses the energy of lasers to swiftly and accurately transfer Micro-LEDs from the substrate to the target substrate, enabling rapid device transfer. Lastly, laser repair technology is employed for the detection and repair of potential defects in Micro-LEDs, enhancing device quality and reliability. By utilizing lasers, we can expect to achieve higher production efficiency, more precise device manufacturing, and superior optoelectronic performance in the field of Micro-LED, thereby presenting broader prospects for future display technology and lighting applications. These laser technologies provide new solutions for Micro-LED devices’ high-precision and high-efficiency production.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-03DOI: 10.1016/j.optlastec.2024.111586
Qiuying Ma, Haoyang Yu, Hao Li, Kaiyang Ding, Xiaojun Liang, Xiaohao Wang, Qian Zhou, Kai Ni
Dual combs are widely recognized for their significant applications in precision measurement, due to their high spectral resolution, broad spectral range and high speed. However, the tight locking dual-comb system faces challenges in terms of complexity, cost, and power consumption, limiting their widespread field applications. We introduced a free-running dual-comb system based on environment-shared fiber lasers with passively thermal management. This thermal management system features a novel three-layer thermal shielding cavity, designed using a mathematical model based on an analogy with an RC filter circuit. This method allows for optimized design parameters, reducing both complexity and cost. To confirm its effectiveness, we validate the proposed method through both finite element analysis and experiments. Our all-fiber, free-running dual-comb system demonstrates excellent stability in the repetition frequency difference and the sub-comb radio frequency spectrum, providing a straightforward and viable solution for field-deployable applications.
{"title":"Free-running dual-comb system based on environment-shared fiber lasers with passively thermal management","authors":"Qiuying Ma, Haoyang Yu, Hao Li, Kaiyang Ding, Xiaojun Liang, Xiaohao Wang, Qian Zhou, Kai Ni","doi":"10.1016/j.optlastec.2024.111586","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111586","url":null,"abstract":"Dual combs are widely recognized for their significant applications in precision measurement, due to their high spectral resolution, broad spectral range and high speed. However, the tight locking dual-comb system faces challenges in terms of complexity, cost, and power consumption, limiting their widespread field applications. We introduced a free-running dual-comb system based on environment-shared fiber lasers with passively thermal management. This thermal management system features a novel three-layer thermal shielding cavity, designed using a mathematical model based on an analogy with an RC filter circuit. This method allows for optimized design parameters, reducing both complexity and cost. To confirm its effectiveness, we validate the proposed method through both finite element analysis and experiments. Our all-fiber, free-running dual-comb system demonstrates excellent stability in the repetition frequency difference and the sub-comb radio frequency spectrum, providing a straightforward and viable solution for field-deployable applications.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-03DOI: 10.1016/j.optlastec.2024.111725
Fan-Chuan Lin, Qian Huang, Yi-Wei Zheng, Di Wang, Qiong-Hua Wang
Holographic technology is considered as one of the most ideal 3D display technologies and has significant potential in near-eye display. However, binocular holographic near-eye 3D display still faces challenges such as serious visual fatigue and complex system. Here, we propose a compact binocular holographic near-eye 3D display system based on a liquid crystal polarization grating (LCPG). Based on the LCPG, the reconstructed light can be deflected respectively to left and right viewing areas. The proposed system achieves binocular display with only one phase-only spatial light modulator used to load computer-generated hologram, which makes the binocular display system more compact. Simultaneously, the proposed system reduces mismatches in the images perceived by two eyes, thus achieving a better binocular display effect. Experimental results demonstrate the feasibility of the proposed binocular holographic near-eye 3D display system with dual viewing areas. Additionally, based on the time-division multiplexing method, dynamic binocular holographic near-eye display can be achieved. The proposed system has potential applications in holographic virtual reality and augmented reality display.
全息技术被认为是最理想的三维显示技术之一，在近眼显示领域具有巨大潜力。然而，双目全息近眼 3D 显示仍然面临着严重的视觉疲劳和系统复杂等挑战。在此，我们提出了一种基于液晶偏振光栅（LCPG）的紧凑型双目全息近眼 3D 显示系统。基于液晶偏振光栅，重建光可以分别偏转到左右视角区域。该系统只需一个用于加载计算机生成的全息图的纯相位空间光调制器就能实现双目显示，从而使双目显示系统更加紧凑。同时，所提出的系统减少了双眼感知图像的不匹配，从而实现了更好的双目显示效果。实验结果证明了双目全息近眼三维显示系统的可行性。此外，基于时分复用方法，还可以实现动态双目全息近眼显示。该系统有望应用于全息虚拟现实和增强现实显示。
{"title":"Compact binocular holographic near-eye 3D display system based on a liquid crystal polarization grating","authors":"Fan-Chuan Lin, Qian Huang, Yi-Wei Zheng, Di Wang, Qiong-Hua Wang","doi":"10.1016/j.optlastec.2024.111725","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111725","url":null,"abstract":"Holographic technology is considered as one of the most ideal 3D display technologies and has significant potential in near-eye display. However, binocular holographic near-eye 3D display still faces challenges such as serious visual fatigue and complex system. Here, we propose a compact binocular holographic near-eye 3D display system based on a liquid crystal polarization grating (LCPG). Based on the LCPG, the reconstructed light can be deflected respectively to left and right viewing areas. The proposed system achieves binocular display with only one phase-only spatial light modulator used to load computer-generated hologram, which makes the binocular display system more compact. Simultaneously, the proposed system reduces mismatches in the images perceived by two eyes, thus achieving a better binocular display effect. Experimental results demonstrate the feasibility of the proposed binocular holographic near-eye 3D display system with dual viewing areas. Additionally, based on the time-division multiplexing method, dynamic binocular holographic near-eye display can be achieved. The proposed system has potential applications in holographic virtual reality and augmented reality display.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The conventional distributed fiber optic positioning system (DFOPS) employing a single pulse working has a mutually constrained relationship between resolution and measurement distance, thereby imposing severe limitations on the advancement of DFOPS development. To solve this problem, we propose a strain and vibration event positioning system by employing correlated positioning techniques, pulse coding techniques, a broadband light source, and arrays of weakly reflective fiber gratings. To further improve the positioning accuracy of the system, the chip subdivision method and correlation prediction method are used to achieve centimeter-level localization accuracy in this study. In addition to correlation localization, we also propose a superposition signal decomposition model to achieve vibration event localization. Finally, to determine the most appropriate coding method for the system, a comparative analysis is performed to evaluate different coding methods in terms of coding gain, transmission time, and decoding complexity. We hope that the system and methods presented in this paper can serve as a valuable reference in the field of distributed fiber optic sensing with grating arrays for vibration detection.
{"title":"High-Precision distributed fiber optic vibration positioning system with grating array","authors":"Yulin Wang, Yunfan Xu, Sen Zhu, Yanyan Liu, Weibin Feng, Xinxing Ma, Yuefeng Qi","doi":"10.1016/j.optlastec.2024.111721","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111721","url":null,"abstract":"The conventional distributed fiber optic positioning system (DFOPS) employing a single pulse working has a mutually constrained relationship between resolution and measurement distance, thereby imposing severe limitations on the advancement of DFOPS development. To solve this problem, we propose a strain and vibration event positioning system by employing correlated positioning techniques, pulse coding techniques, a broadband light source, and arrays of weakly reflective fiber gratings. To further improve the positioning accuracy of the system, the chip subdivision method and correlation prediction method are used to achieve centimeter-level localization accuracy in this study. In addition to correlation localization, we also propose a superposition signal decomposition model to achieve vibration event localization. Finally, to determine the most appropriate coding method for the system, a comparative analysis is performed to evaluate different coding methods in terms of coding gain, transmission time, and decoding complexity. We hope that the system and methods presented in this paper can serve as a valuable reference in the field of distributed fiber optic sensing with grating arrays for vibration detection.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-03DOI: 10.1016/j.optlastec.2024.111697
Hua-Long Du, Nuerguli Kari, Ben Li, Qi Wang
The fiber Surface plasmon resonance (SPR) sensor based on titanium dioxide(TiO) and Au nanoparticles (Au-NPs) sensitization is offered as a practical means of increasing the sensitivity and figure of merit (FOM). Through finite element simulation and experimental testing, it is found that in TiO with high dielectric constant and high dielectric conductivity, the carrier movement is fast and consumption is low, which enhances the photocurrent signal and leads to charge redistribution, thus enhances the electric field; while the Au-NPs will stimulate the stronger Localized Surface plasmon resonance (LSPR) phenomenon, and both of them will undergo electric field resonance coupling. The sensitivity of the sensor is higher because its surface electric field is 3.67 times stronger than the conventional Au film sensor. When exposed to external conditions, the sensitivity can reach 9715 nm/RIU within the refractive index (RI) at 1.33213–1.34055, which is 4.69 times higher than a conventional Au film sensor. The FOM can reach 57.8 RIU, which is 2.05 times higher than the conventional Au film sensor. In addition, TiO and Au-NPs on the surface of the sensor are less prone to collapse, and the stability test results show that the relative standard deviation (RSD) is 0.5929 %, which exhibits good reliability and stability. The structure of the sensor is very simple, relatively easy to fabricate, and has good applicability in the field of biochemical testing.
{"title":"The fiber surface plasmon resonance sensor based on TiO2 /Au-NPs sensitization","authors":"Hua-Long Du, Nuerguli Kari, Ben Li, Qi Wang","doi":"10.1016/j.optlastec.2024.111697","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111697","url":null,"abstract":"The fiber Surface plasmon resonance (SPR) sensor based on titanium dioxide(TiO) and Au nanoparticles (Au-NPs) sensitization is offered as a practical means of increasing the sensitivity and figure of merit (FOM). Through finite element simulation and experimental testing, it is found that in TiO with high dielectric constant and high dielectric conductivity, the carrier movement is fast and consumption is low, which enhances the photocurrent signal and leads to charge redistribution, thus enhances the electric field; while the Au-NPs will stimulate the stronger Localized Surface plasmon resonance (LSPR) phenomenon, and both of them will undergo electric field resonance coupling. The sensitivity of the sensor is higher because its surface electric field is 3.67 times stronger than the conventional Au film sensor. When exposed to external conditions, the sensitivity can reach 9715 nm/RIU within the refractive index (RI) at 1.33213–1.34055, which is 4.69 times higher than a conventional Au film sensor. The FOM can reach 57.8 RIU, which is 2.05 times higher than the conventional Au film sensor. In addition, TiO and Au-NPs on the surface of the sensor are less prone to collapse, and the stability test results show that the relative standard deviation (RSD) is 0.5929 %, which exhibits good reliability and stability. The structure of the sensor is very simple, relatively easy to fabricate, and has good applicability in the field of biochemical testing.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The influence of the coupling effect between dynamic power and oscillation path on the formation of weld seams and the fluid behavior of the molten pool during laser welding of 5A06 aluminum alloy was investigated through numerical simulation and experimentation. Three power modes were compared in the experiments: equal power (EP), delayed dynamic power (D-DP), and non-delayed dynamic power (ND-DP). The experimental results show that both D-DP and ND-DP modes are favorable to improve the mechanical properties. Among them, the joints formed under the D-DP mode exhibit the best mechanical properties, with an average tensile strength reaching ≈ 99.1% of the base material, which is an increase of ≈ 35.3% and ≈ 5.6% compared to the EP and ND-DP modes, respectively. Numerical simulation results indicate that the D-DP mode effectively mitigates the average flow velocity of the molten pool, reduces the collision effects between liquid flows, suppresses the impact of fluid on the keyhole walls, and improves the stability of the keyhole and the welding process, thereby enhancing the mechanical properties of the joints.
{"title":"Coupling effect of dynamic power and oscillation path on butt weld formation and melt flow behavior during aluminum alloys","authors":"Jiangmei Cui, J.P. Oliveira, Bowen Pang, Jiajia Shen, Zhi Zeng","doi":"10.1016/j.optlastec.2024.111687","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111687","url":null,"abstract":"The influence of the coupling effect between dynamic power and oscillation path on the formation of weld seams and the fluid behavior of the molten pool during laser welding of 5A06 aluminum alloy was investigated through numerical simulation and experimentation. Three power modes were compared in the experiments: equal power (EP), delayed dynamic power (D-DP), and non-delayed dynamic power (ND-DP). The experimental results show that both D-DP and ND-DP modes are favorable to improve the mechanical properties. Among them, the joints formed under the D-DP mode exhibit the best mechanical properties, with an average tensile strength reaching ≈ 99.1% of the base material, which is an increase of ≈ 35.3% and ≈ 5.6% compared to the EP and ND-DP modes, respectively. Numerical simulation results indicate that the D-DP mode effectively mitigates the average flow velocity of the molten pool, reduces the collision effects between liquid flows, suppresses the impact of fluid on the keyhole walls, and improves the stability of the keyhole and the welding process, thereby enhancing the mechanical properties of the joints.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"117 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-02DOI: 10.1016/j.optlastec.2024.111724
Xiaobing Li, Yang Zhang, Mingyu Liu, Jiayan Li, Jiayang Sun, Wenzhi Wu, Degui Kong
Based on Richards-Wolf vector diffraction theory, the tight focusing properties of radially polarized chirped circular Airy vortex beams (RP-CCAVBs) are theoretically investigated using a high numerical aperture objective lens in the paper. The results shown that super-resolution scalable optical needles, dark channels, elliptical optical cages, and optical oscillations can be obtained by adjusting the scale factor, exponential attenuation coefficient, main ring radius, and topological charge of optical vortex in the incident RP-CCAVBs. The DOF of optical needle and dark channels is exponent dependent on scaling factor ω of RP-CCAVBs. And the position optical needle and dark channels can be moved by changing chirped parameter of RP-CCAVBs. The size of obtained optical cages can be adjusted by changing the radius of main rings in RP-CCAVBs. The intensity distribution of the obtained optical oscillations is intensely affected by parameter and chirp parameter of RP-CCAVBs.
{"title":"Generation of variable light fields by radially polarized chirped circular Airy vortex beams","authors":"Xiaobing Li, Yang Zhang, Mingyu Liu, Jiayan Li, Jiayang Sun, Wenzhi Wu, Degui Kong","doi":"10.1016/j.optlastec.2024.111724","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111724","url":null,"abstract":"Based on Richards-Wolf vector diffraction theory, the tight focusing properties of radially polarized chirped circular Airy vortex beams (RP-CCAVBs) are theoretically investigated using a high numerical aperture objective lens in the paper. The results shown that super-resolution scalable optical needles, dark channels, elliptical optical cages, and optical oscillations can be obtained by adjusting the scale factor, exponential attenuation coefficient, main ring radius, and topological charge of optical vortex in the incident RP-CCAVBs. The DOF of optical needle and dark channels is exponent dependent on scaling factor ω of RP-CCAVBs. And the position optical needle and dark channels can be moved by changing chirped parameter of RP-CCAVBs. The size of obtained optical cages can be adjusted by changing the radius of main rings in RP-CCAVBs. The intensity distribution of the obtained optical oscillations is intensely affected by parameter and chirp parameter of RP-CCAVBs.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"285 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-02DOI: 10.1016/j.optlastec.2024.111690
Gharam A. Alharshan, H.A. Saudi, Shams A.M. Issa, Hesham M.H. Zakaly, Hosam M. Gomaa
The optical response in materials offers valuable insights into their properties, especially regarding interband transitions, distinct from direct current responses. By adjusting the frequency of electromagnetic radiation, interband transitions and energy band mappings can be explored, even in materials like graphene. Optical conductivity, which measures a material’s ability to conduct electricity under the influence of light, is pivotal across physics, materials science, and engineering. It quantifies a material’s efficiency in absorbing and transporting electromagnetic energy as photons. Typically described by Drude’s model, optical conductivity has applications in diverse fields, from designing specific optical properties in materials to optimizing solar cells and developing photonic devices. Plasmonics, meta-materials, and renewable energy research also benefit from understanding and controlling optical conductivity. The optical conductivity problem centers on comprehending materials’ electrical interactions with light across the optical spectrum, which is vital for various technologies. Theoretical models, simulations, and experiments address this problem, aiming to develop tunable materials and enhance theoretical models for accurate prediction of optical properties. Mathematical models, such as Maxwell’s equations, the Lorentz-Drude model, and the Hosam-Heba model, elucidate optical conductivity, aiding in understanding light-material interactions and predicting material behavior under electromagnetic radiation. Each model offers a unique perspective on optical conductivity, with different theoretical foundations and mathematical formulations that can be applied depending on the specific properties of the material being studied. Understanding and manipulating optical conductivity is foundational to utilizing light across various technological applications.
{"title":"Shedding light on and comparing three different mathematical models of the optical conductivity concept","authors":"Gharam A. Alharshan, H.A. Saudi, Shams A.M. Issa, Hesham M.H. Zakaly, Hosam M. Gomaa","doi":"10.1016/j.optlastec.2024.111690","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111690","url":null,"abstract":"The optical response in materials offers valuable insights into their properties, especially regarding interband transitions, distinct from direct current responses. By adjusting the frequency of electromagnetic radiation, interband transitions and energy band mappings can be explored, even in materials like graphene. Optical conductivity, which measures a material’s ability to conduct electricity under the influence of light, is pivotal across physics, materials science, and engineering. It quantifies a material’s efficiency in absorbing and transporting electromagnetic energy as photons. Typically described by Drude’s model, optical conductivity has applications in diverse fields, from designing specific optical properties in materials to optimizing solar cells and developing photonic devices. Plasmonics, meta-materials, and renewable energy research also benefit from understanding and controlling optical conductivity. The optical conductivity problem centers on comprehending materials’ electrical interactions with light across the optical spectrum, which is vital for various technologies. Theoretical models, simulations, and experiments address this problem, aiming to develop tunable materials and enhance theoretical models for accurate prediction of optical properties. Mathematical models, such as Maxwell’s equations, the Lorentz-Drude model, and the Hosam-Heba model, elucidate optical conductivity, aiding in understanding light-material interactions and predicting material behavior under electromagnetic radiation. Each model offers a unique perspective on optical conductivity, with different theoretical foundations and mathematical formulations that can be applied depending on the specific properties of the material being studied. Understanding and manipulating optical conductivity is foundational to utilizing light across various technological applications.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hollow-laser Direct Energy Deposition (HL-DED) significantly surpasses traditional Laser Directed Energy Deposition (L-DED) methods, marked by its superior adjustability of energy density, exacting control of energy distribution, and versatility in creating cladding layers of varied geometries. This novel technique ensures a markedly uniform and stable melt path. In this paper, the HL-DED process was systematically analyzed by combining numerical simulation and experimental research. A novel three-dimensional transient computational fluid dynamics (CFD) simulation model is established based on the Flow 3D software to study the flow and heat and mass transfer behaviors. At the optimized processing parameters, the single-track and multi-track cladding layer processes were carried out respectively. Results show that the model can well predict and explain the flow of the molten pool and the morphology of the cladding layer in the HL-DED process. In the initial stage of single-track cladding, the molten pool exhibits a symmetrical bimodal distribution configuration characterized by the peak flow rate of 0.09 m/s, with temperatures being higher at the periphery and lower at the center. In the stabilization phase, the dynamics of the molten pool are primarily influenced by gas-powder momentum transfer, showing increased peak flow rates up to 0.26 m/s. Concurrently, the peripheral temperatures rise from 2001 K to 2122 K (0.06 % increase), but central temperatures ascend from 1400 K to 1800 K (0.29 % increase). The flow and temperature distribution patterns in multi-track cladding closely mirror those observed in single-track layers, maintaining a symmetrical bimodal temperature distribution with peak flow rates reaching 0.105 m/s. The temperature distribution evolves from a unimodal to a bimodal pattern, with the left peak approximately 100 K higher than the right, before reverting to a unimodal configuration. Simulation outcomes closely align with experimental findings, offering valuable insights for refining the experimental adjustment of the internal optical coaxial powder feeding process.
中空激光直接能量沉积（HL-DED）大大超越了传统的激光定向能量沉积（L-DED）方法，其显著特点是能量密度的可调节性、能量分布的精确控制以及创建不同几何形状包覆层的多功能性。这种新型技术可确保熔体路径明显均匀稳定。本文结合数值模拟和实验研究，对 HL-DED 工艺进行了系统分析。基于 Flow 3D 软件建立了新型三维瞬态计算流体动力学（CFD）仿真模型，以研究流动、传热和传质行为。在优化的加工参数下，分别进行了单轨和多轨覆层工艺。结果表明，该模型可以很好地预测和解释 HL-DED 工艺中熔池的流动和熔覆层的形态。在单轨包覆的初始阶段，熔池呈现对称的双峰分布构型，峰值流速为 0.09 m/s，温度在外围较高，在中心较低。在稳定阶段，熔池的动态主要受气体-粉末动量传递的影响，峰值流速增加到 0.26 m/s。同时，外围温度从 2001 K 上升到 2122 K（上升 0.06%），但中心温度从 1400 K 上升到 1800 K（上升 0.29%）。多轨道包层中的流动和温度分布模式与单轨道层中的流动和温度分布模式非常相似，保持了对称的双峰温度分布，峰值流速达到 0.105 m/s。温度分布从单模模式演变为双模模式，左侧峰值比右侧峰值高出约 100 K，然后又恢复到单模配置。模拟结果与实验结果非常吻合，为完善内部光学同轴粉末进给过程的实验调整提供了宝贵的见解。
{"title":"Numerical simulation and experimental research of molten pool flow field and temperature field by hollow-laser direct energy deposition","authors":"Gangxian Zhu, Lele Zhao, Jiaqin Luo, Jiaqiang Li, Xing Zhang","doi":"10.1016/j.optlastec.2024.111732","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111732","url":null,"abstract":"Hollow-laser Direct Energy Deposition (HL-DED) significantly surpasses traditional Laser Directed Energy Deposition (L-DED) methods, marked by its superior adjustability of energy density, exacting control of energy distribution, and versatility in creating cladding layers of varied geometries. This novel technique ensures a markedly uniform and stable melt path. In this paper, the HL-DED process was systematically analyzed by combining numerical simulation and experimental research. A novel three-dimensional transient computational fluid dynamics (CFD) simulation model is established based on the Flow 3D software to study the flow and heat and mass transfer behaviors. At the optimized processing parameters, the single-track and multi-track cladding layer processes were carried out respectively. Results show that the model can well predict and explain the flow of the molten pool and the morphology of the cladding layer in the HL-DED process. In the initial stage of single-track cladding, the molten pool exhibits a symmetrical bimodal distribution configuration characterized by the peak flow rate of 0.09 m/s, with temperatures being higher at the periphery and lower at the center. In the stabilization phase, the dynamics of the molten pool are primarily influenced by gas-powder momentum transfer, showing increased peak flow rates up to 0.26 m/s. Concurrently, the peripheral temperatures rise from 2001 K to 2122 K (0.06 % increase), but central temperatures ascend from 1400 K to 1800 K (0.29 % increase). The flow and temperature distribution patterns in multi-track cladding closely mirror those observed in single-track layers, maintaining a symmetrical bimodal temperature distribution with peak flow rates reaching 0.105 m/s. The temperature distribution evolves from a unimodal to a bimodal pattern, with the left peak approximately 100 K higher than the right, before reverting to a unimodal configuration. Simulation outcomes closely align with experimental findings, offering valuable insights for refining the experimental adjustment of the internal optical coaxial powder feeding process.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Third harmonic generation (THG) by laser filamentation in gases is immune to the damage threshold and phase matching limit for UV and EUV pulse generation. Here, we report on the jitter measurements of the beam pointing and the intensity of the THG through filamentation with different repetition rates in air. The THG jitters are stronger at the high repetition rates (1 kHz) filaments. A technique of applying an external DC electric field on the filament was found to suppress the jitters. The beam pointing and intensity jitters of the 1 kHz THG from laser filament in air were reduced by about 1 fold with the extreme external electric field electric field applied on the filament. This technique provides a way to generate a stable, high repetition rate UV and EUV sources.
{"title":"Improving the beam pointing and intensity stability of the third harmonic generated in air filament","authors":"Fukang Yin, Yaoxiang Liu, Tie-Jun Wang, Yingxia Wei, Juan Long, Hengyi Zheng, Chengpu Liu, Yuxin Leng","doi":"10.1016/j.optlastec.2024.111717","DOIUrl":"https://doi.org/10.1016/j.optlastec.2024.111717","url":null,"abstract":"Third harmonic generation (THG) by laser filamentation in gases is immune to the damage threshold and phase matching limit for UV and EUV pulse generation. Here, we report on the jitter measurements of the beam pointing and the intensity of the THG through filamentation with different repetition rates in air. The THG jitters are stronger at the high repetition rates (1 kHz) filaments. A technique of applying an external DC electric field on the filament was found to suppress the jitters. The beam pointing and intensity jitters of the 1 kHz THG from laser filament in air were reduced by about 1 fold with the extreme external electric field electric field applied on the filament. This technique provides a way to generate a stable, high repetition rate UV and EUV sources.","PeriodicalId":19597,"journal":{"name":"Optics & Laser Technology","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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