Pub Date : 2024-11-24DOI: 10.1016/j.optlastec.2024.112144
Feiyun Fang, Zhaoying Wang
We construct an electromagnetic induction imaging (EMI) system based on a SERF (Spin-Exchange-Relaxation-Free) atomic magnetometer. The homemade SERF magnetometer relies on the optical magnetic resonance absorption to obtain the magnitude of the secondary magnetic fields of object, and only one laser beam is used for both pumping and detection. Besides, by using sub-harmonics in beating signal, the scheme of the imaging system is simplified with fast Fourier transform (FFT) instead of the lock-in amplifier. Overall, our scheme has a simple structure, which is very conducive to miniaturization and portability. In our experiment, the frequency regions of RF and the corresponding magnitude of the generational secondary magnetic field are both investigated to find that the optimal operation RF frequency is about kHz, which lead to a deeper object’s penetration depth. Furthermore, due to the high sensitivity of SERF atomic magnetometer, we can have a clear imaging based solely on the magnitude of the secondary magnetic fields without the information of its phase.
{"title":"Electromagnetic induction imaging with a SERF atomic magnetometer","authors":"Feiyun Fang, Zhaoying Wang","doi":"10.1016/j.optlastec.2024.112144","DOIUrl":"10.1016/j.optlastec.2024.112144","url":null,"abstract":"<div><div>We construct an electromagnetic induction imaging (EMI) system based on a SERF (Spin-Exchange-Relaxation-Free) atomic magnetometer. The homemade SERF magnetometer relies on the optical magnetic resonance absorption to obtain the magnitude of the secondary magnetic fields of object, and only one laser beam is used for both pumping and detection. Besides, by using sub-harmonics in beating signal, the scheme of the imaging system is simplified with fast Fourier transform (FFT) instead of the lock-in amplifier. Overall, our scheme has a simple structure, which is very conducive to miniaturization and portability. In our experiment, the frequency regions of RF and the corresponding magnitude of the generational secondary magnetic field are both investigated to find that the optimal operation RF frequency is about kHz, which lead to a deeper object’s penetration depth. Furthermore, due to the high sensitivity of SERF atomic magnetometer, we can have a clear imaging based solely on the magnitude of the secondary magnetic fields without the information of its phase.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112144"},"PeriodicalIF":4.6,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-24DOI: 10.1016/j.optlastec.2024.112148
Zhigang Jiang , Shengshui Wang , Min Xu , Wei Wang , Chaoyang Wei , Zhenqi Niu
Single-crystal thin-film lithium niobate (TFLN) photonic devices have become a highly popular research area in recent years. The mask-chemical mechanical polishing (CMP) etching technique for TFLN photonic devices has garnered significant attention due to its potential for the efficient and large-scale fabrication of integrated photonic device microstructures. This paper focuses on the physical processes involved in etching TFLN waveguide microstructures using mask-CMP technology. Innovatively, the pressure distribution function of a superelastic polishing pad is combined with the Preston equation to establish a finite element theoretical model. Based on this model, systematic theoretical calculations and analyses were conducted on factors affecting etching efficiency and waveguide structure, such as load magnitude, contact pressure, and mask dimensions. The simulation results were compared with experimental data. This research provides a theoretical reference for advancing the large-scale, high-efficiency fabrication of TFLN photonic chips using mask-CMP etching technology.
{"title":"Fabrication of on-chip single-crystal lithium niobate waveguide microstructures based on mask-chemical mechanical polishing technology","authors":"Zhigang Jiang , Shengshui Wang , Min Xu , Wei Wang , Chaoyang Wei , Zhenqi Niu","doi":"10.1016/j.optlastec.2024.112148","DOIUrl":"10.1016/j.optlastec.2024.112148","url":null,"abstract":"<div><div>Single-crystal thin-film lithium niobate (TFLN) photonic devices have become a highly popular research area in recent years. The mask-chemical mechanical polishing (CMP) etching technique for TFLN photonic devices has garnered significant attention due to its potential for the efficient and large-scale fabrication of integrated photonic device microstructures. This paper focuses on the physical processes involved in etching TFLN waveguide microstructures using mask-CMP technology. Innovatively, the pressure distribution function of a superelastic polishing pad is combined with the Preston equation to establish a finite element theoretical model. Based on this model, systematic theoretical calculations and analyses were conducted on factors affecting etching efficiency and waveguide structure, such as load magnitude, contact pressure, and mask dimensions. The simulation results were compared with experimental data. This research provides a theoretical reference for advancing the large-scale, high-efficiency fabrication of TFLN photonic chips using mask-CMP etching technology.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112148"},"PeriodicalIF":4.6,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-24DOI: 10.1016/j.optlastec.2024.112120
Yang Li , Yan Li , Jingru Wang , Zejia Zhao , Adnan Khan , Ming Feng , Feng Song
The utilization of a stable orthogonally polarized laser can promote the head-mounted miniature fluorescence microscopy into a powerful tool for real-time intracerebral three-dimensional observation. However, the realization of wearable dual-wavelength polarized light sources has remained an attractive challenge to break through the spatial constraints of transmitting fiber-optic paths. Herein, we have proposed a modularized orthogonal-polarization dual-wavelength microcavity enabled by high reflectance (HR) and output-coupled (OC) gradient-composite multi-dimensional meta-filters, where these printable meta-filters are composed of two nanocomposite metasurfaces (NCMSs). Specifically, based on the Mie surface lattice resonances (Mie-SLR), the designed NCMSs can realize tunable multi-parameter filtering at diverse dimensions (wavelength, polarization, and incident angle) by optimizing the lattice distances. By virtue of the sandwich-type gradient-composite configuration, the proposed meta-filters have integrated orthogonal-polarization filtering of two independent NCMS at 1064 nm and 1320 nm. The stability of the multi-dimensional filtering capabilities of the proposed meta-filters has been enhanced by optimizing the thickness of the resin bonding layers in the gradient-composite structure. Without other nonlinear modulation, orthogonal-polarization dual-wavelength mode oscillations can be developed only by passive multi-dimensional filtering of HR and OC meta-filters in the microcavity. These proposed new-generation gradient-composite multi-dimensional meta-filters will provide novel strategies toward high-robust miniature light sources for wearable optical devices.
{"title":"Modularized orthogonal-polarization dual-wavelength microcavity based on light curing gradient-composite multi-dimensional meta-filters","authors":"Yang Li , Yan Li , Jingru Wang , Zejia Zhao , Adnan Khan , Ming Feng , Feng Song","doi":"10.1016/j.optlastec.2024.112120","DOIUrl":"10.1016/j.optlastec.2024.112120","url":null,"abstract":"<div><div>The utilization of a stable orthogonally polarized laser can promote the head-mounted miniature fluorescence microscopy into a powerful tool for real-time intracerebral three-dimensional observation. However, the realization of wearable dual-wavelength polarized light sources has remained an attractive challenge to break through the spatial constraints of transmitting fiber-optic paths. Herein, we have proposed a modularized orthogonal-polarization dual-wavelength microcavity enabled by high reflectance (HR) and output-coupled (OC) gradient-composite multi-dimensional meta-filters, where these printable meta-filters are composed of two nanocomposite metasurfaces (NCMSs). Specifically, based on the Mie surface lattice resonances (Mie-SLR), the designed NCMSs can realize tunable multi-parameter filtering at diverse dimensions (wavelength, polarization, and incident angle) by optimizing the lattice distances. By virtue of the sandwich-type gradient-composite configuration, the proposed meta-filters have integrated orthogonal-polarization filtering of two independent NCMS at 1064 nm and 1320 nm. The stability of the multi-dimensional filtering capabilities of the proposed meta-filters has been enhanced by optimizing the thickness of the resin bonding layers in the gradient-composite structure. Without other nonlinear modulation, orthogonal-polarization dual-wavelength mode oscillations can be developed only by passive multi-dimensional filtering of HR and OC meta-filters in the microcavity. These proposed new-generation gradient-composite multi-dimensional meta-filters will provide novel strategies toward high-robust miniature light sources for wearable optical devices.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112120"},"PeriodicalIF":4.6,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-23DOI: 10.1016/j.optlastec.2024.112140
Renwu Jiang , Ziyu Chen , Yongqiang Yang , Zixin Liu , Changjun Han , Yu Long , Yingjie Zhang , Xingchen Yan , Liming Lei , Haoran Li , Di Wang
During multi-laser powder bed fusion (ML-PBF) process, spatters increase with the number of lasers employed in the printing process. The flow velocity of shielding gas plays a crucial role in determining part quality, and thus warrants further investigation into its interaction with multi-laser scanning strategies. In this work, two multi-laser scanning strategies, i.e., parallel scanning (single laser operating) and simultaneous scanning (two lasers operating simultaneously) along the gas flow direction, within a range of flow velocity from 0 to 3 m/s, were employed to print 316L parts. The effect of the flow velocity and multi-laser scanning strategy on the surface quality, internal defects, and microhardness of 316L printed via ML-PBF were investigated. Both multi-laser scanning strategies obtained minimum surface roughness at an upstream area within the flow velocity range of 2–3 m/s, due to the elimination of balling phenomenon and the improvement of large spatters attachment. The printed 316L alloy achieved a density of over 99 % and an average microhardness exceeding 180 HV when the flow velocity exceeded 2 m/s in simultaneous scanning and 1 m/s in parallel scanning. The superior mechanical properties were attributed to the decrease in both the number and size of lack-of-fusion defects. Additionally, spatters generated at the upstream areas had a detrimental impact on the sample quality at the downstream areas, resulting in inferior surface quality and density. These findings provide valuable insights into the importance of considering flow velocity as a crucial process parameter, in addition to optimizing multi-laser scanning strategies.
在多激光粉末床熔融（ML-PBF）过程中，喷溅物会随着打印过程中激光器数量的增加而增加。屏蔽气体的流速在决定零件质量方面起着至关重要的作用，因此需要进一步研究其与多激光扫描策略之间的相互作用。在这项工作中，采用了两种多激光扫描策略，即沿气体流动方向的平行扫描（单激光器工作）和同步扫描（两台激光器同时工作），在 0 至 3 m/s 的流速范围内打印 316L 零件。研究了流速和多激光扫描策略对通过 ML-PBF 打印的 316L 的表面质量、内部缺陷和显微硬度的影响。在 2-3 m/s 的流速范围内，两种多激光扫描策略都能在上游区域获得最小的表面粗糙度，原因是消除了起球现象并改善了大飞溅物的附着。当同步扫描的流速超过 2 m/s、平行扫描的流速超过 1 m/s 时，打印出的 316L 合金密度超过 99%，平均显微硬度超过 180 HV。优异的机械性能得益于熔合缺陷数量和尺寸的减少。此外，上游区域产生的飞溅物对下游区域的样品质量有不利影响，导致表面质量和密度变差。这些发现为我们提供了宝贵的启示，即除了优化多激光扫描策略外，还必须将流速视为关键的工艺参数。
{"title":"Effect of gas flow velocity and multi-laser scanning strategy on surface quality and mechanical properties of 316L parts printed by multi-laser powder bed fusion","authors":"Renwu Jiang , Ziyu Chen , Yongqiang Yang , Zixin Liu , Changjun Han , Yu Long , Yingjie Zhang , Xingchen Yan , Liming Lei , Haoran Li , Di Wang","doi":"10.1016/j.optlastec.2024.112140","DOIUrl":"10.1016/j.optlastec.2024.112140","url":null,"abstract":"<div><div>During multi-laser powder bed fusion (ML-PBF) process, spatters increase with the number of lasers employed in the printing process. The flow velocity of shielding gas plays a crucial role in determining part quality, and thus warrants further investigation into its interaction with multi-laser scanning strategies. In this work, two multi-laser scanning strategies, i.e., parallel scanning (single laser operating) and simultaneous scanning (two lasers operating simultaneously) along the gas flow direction, within a range of flow velocity from 0 to 3 m/s, were employed to print 316L parts. The effect of the flow velocity and multi-laser scanning strategy on the surface quality, internal defects, and microhardness of 316L printed via ML-PBF were investigated. Both multi-laser scanning strategies obtained minimum surface roughness at an upstream area within the flow velocity range of 2–3 m/s, due to the elimination of balling phenomenon and the improvement of large spatters attachment. The printed 316L alloy achieved a density of over 99 % and an average microhardness exceeding 180 HV when the flow velocity exceeded 2 m/s in simultaneous scanning and 1 m/s in parallel scanning. The superior mechanical properties were attributed to the decrease in both the number and size of lack-of-fusion defects. Additionally, spatters generated at the upstream areas had a detrimental impact on the sample quality at the downstream areas, resulting in inferior surface quality and density. These findings provide valuable insights into the importance of considering flow velocity as a crucial process parameter, in addition to optimizing multi-laser scanning strategies.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112140"},"PeriodicalIF":4.6,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-23DOI: 10.1016/j.optlastec.2024.112175
Wei Feng , Zhuangzhuang Mao , Heng Ma , Hongye Zhang , Yao Zhao , Kai Zhao , Chaoqi Qi , Ce Hao , Jiaqiang Li , Sheng Liu , Xin Kang , Jianxin Nie , Zhanwei Liu
Deposited height deviation (DHD) of printed layers is a common surface defect that restricts vertical printing accuracy during the additive manufacturing process. The accumulation of DHD layer by layer inevitably leads to the failure of subsequent additive manufacturing tasks. Therefore, accurate online measurement of DHD is crucial. This study proposed a novel amplification computer-vision measurement (ACVM) method that effectively utilizes both melt pool images and temperature information, achieving a DHD detection sensitivity of approximately 9.96 μm. Theoretical connections between image features and DHD, as well as the theoretical associations between instantaneous temperature characteristic and DHD, have been systematically deduced. Based on these two theoretical relationships, DHD can be accurately and synchronously detected directly through the positions of image features and temperature. A single-camera dual-channel multi-signal detection (SDMD) system was developed and implemented within a laser-engineered net shaping (LENS) additive manufacturing system. Subsequently, an online measuring and verification experiment was designed to assess the height deviation of thin-walled structural parts. The experimental results demonstrated that the ACVM method provided an early response to DHD. The method exhibits significant technical application value in quality control in future.
{"title":"Online in situ detection of deposited height deviation during additive manufacturing","authors":"Wei Feng , Zhuangzhuang Mao , Heng Ma , Hongye Zhang , Yao Zhao , Kai Zhao , Chaoqi Qi , Ce Hao , Jiaqiang Li , Sheng Liu , Xin Kang , Jianxin Nie , Zhanwei Liu","doi":"10.1016/j.optlastec.2024.112175","DOIUrl":"10.1016/j.optlastec.2024.112175","url":null,"abstract":"<div><div>Deposited height deviation (DHD) of printed layers is a common surface defect that restricts vertical printing accuracy during the additive manufacturing process. The accumulation of DHD layer by layer inevitably leads to the failure of subsequent additive manufacturing tasks. Therefore, accurate online measurement of DHD is crucial. This study proposed a novel amplification computer-vision measurement (ACVM) method that effectively utilizes both melt pool images and temperature information, achieving a DHD detection sensitivity of approximately 9.96 μm. Theoretical connections between image features and DHD, as well as the theoretical associations between instantaneous temperature characteristic and DHD, have been systematically deduced. Based on these two theoretical relationships, DHD can be accurately and synchronously detected directly through the positions of image features and temperature. A single-camera dual-channel multi-signal detection (SDMD) system was developed and implemented within a laser-engineered net shaping (LENS) additive manufacturing system. Subsequently, an online measuring and verification experiment was designed to assess the height deviation of thin-walled structural parts. The experimental results demonstrated that the ACVM method provided an early response to DHD. The method exhibits significant technical application value in quality control in future.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112175"},"PeriodicalIF":4.6,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Holography stands as a significant technology for achieving three-dimensional (3D) wavefront recording and reproductions with continuous depth sensation. Spatial 3D contents can be recovered from a digital hologram using numerical Fresnel back propagation algorithms. However, the space-bandwidth product (SBP) of a holographic 3D imaging system is technically limited to keep the signal spectra away from the unwanted spectra, thereby resulting in a reduced field of view or resolution of an image. In this paper, we proposed a scheme for high bandwidth holographic 3D imaging that uses Kramers–Kronig Fresnel digital holography system. The Kramers–Kronig relations (KKR) are employed to derive the propagated complex wavefront of 3D object from recorded Fresnel digital hologram, then accurate 3D contents of the target object are reconstructed through numerical back-propagation diffraction algorithm. In contrast to the conventional off-axis Fresnel digital holography techniques, the proposed method can suppress streak-like noise and aliasing caused by limited space-bandwidth utilization and depict high-quality reconstructed 3D images.
{"title":"High bandwidth holographic 3D imaging through Kramers–Kronig Fresnel digital holography","authors":"Shaohui Wang, Chenliang Chang, Bo Dai, Qi Wang, Dawei Zhang, Songlin Zhuang","doi":"10.1016/j.optlastec.2024.112180","DOIUrl":"10.1016/j.optlastec.2024.112180","url":null,"abstract":"<div><div>Holography stands as a significant technology for achieving three-dimensional (3D) wavefront recording and reproductions with continuous depth sensation. Spatial 3D contents can be recovered from a digital hologram using numerical Fresnel back propagation algorithms. However, the space-bandwidth product (SBP) of a holographic 3D imaging system is technically limited to keep the signal spectra away from the unwanted spectra, thereby resulting in a reduced field of view or resolution of an image. In this paper, we proposed a scheme for high bandwidth holographic 3D imaging that uses Kramers–Kronig Fresnel digital holography system. The Kramers–Kronig relations (KKR) are employed to derive the propagated complex wavefront of 3D object from recorded Fresnel digital hologram, then accurate 3D contents of the target object are reconstructed through numerical back-propagation diffraction algorithm. In contrast to the conventional off-axis Fresnel digital holography techniques, the proposed method can suppress streak-like noise and aliasing caused by limited space-bandwidth utilization and depict high-quality reconstructed 3D images.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112180"},"PeriodicalIF":4.6,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-23DOI: 10.1016/j.optlastec.2024.112184
Hebin Wu , Mengyu Cao , Fuxaing Liu , Zhang Chong , Yongkang Zhang
The bonding interface serves as the stress load transfer surface of the key bonding structural component of offshore engineering equipment, making its quality detection crucial for ensuring strength and service safety. The laser shock adhesion test is an effective method to detect the bonding quality in the local range by pulsed laser-induced high strain rate shockwave. However, this process requires attention to the propagation and failure mechanism of shockwaves to better understand the energy reference level of spalling in bonded structures. Under laser shock, a combination of simulation and experimental methods was employed to investigate the impact of laser energy and pulse width on the damage characteristics of symmetrically bonded laminated plates with varying thicknesses of bonding plates, elucidating the layered damage mechanism induced by laser shock. It has been observed that the thickness of the bonding plate exhibits a correlation with both the location of damage and the laser energy threshold, under unchanged laser parameters. The thicker the bonding plate, the higher the laser energy threshold becomes, and gradually, the initial location of damage shifts from the impact back to the adhesive layer. With the increase of pulse width, the damage location of the spalling moves from the impact back to the impact surface, and the spalling area increases. The thicker the bonding plate of the symmetrical bonded structure, the greater the selected pulse width, which can enhance spalling effectiveness. Laser energy plays a crucial role in determining spalling outcomes, with higher laser energy resulting in increased spalling damage. The modulation of laser energy and pulse width offers a viable approach for employing the laser shock adhesion testing in non-destructive testing of weak bonding within different material thicknesses composite material bonded structures.
{"title":"Dynamic modeling of the interfacial bonding strength of CFRP composites detected by laser shockwave","authors":"Hebin Wu , Mengyu Cao , Fuxaing Liu , Zhang Chong , Yongkang Zhang","doi":"10.1016/j.optlastec.2024.112184","DOIUrl":"10.1016/j.optlastec.2024.112184","url":null,"abstract":"<div><div>The bonding interface serves as the stress load transfer surface of the key bonding structural component of offshore engineering equipment, making its quality detection crucial for ensuring strength and service safety. The laser shock adhesion test is an effective method to detect the bonding quality in the local range by pulsed laser-induced high strain rate shockwave. However, this process requires attention to the propagation and failure mechanism of shockwaves to better understand the energy reference level of spalling in bonded structures. Under laser shock, a combination of simulation and experimental methods was employed to investigate the impact of laser energy and pulse width on the damage characteristics of symmetrically bonded laminated plates with varying thicknesses of bonding plates, elucidating the layered damage mechanism induced by laser shock. It has been observed that the thickness of the bonding plate exhibits a correlation with both the location of damage and the laser energy threshold, under unchanged laser parameters. The thicker the bonding plate, the higher the laser energy threshold becomes, and gradually, the initial location of damage shifts from the impact back to the adhesive layer. With the increase of pulse width, the damage location of the spalling moves from the impact back to the impact surface, and the spalling area increases. The thicker the bonding plate of the symmetrical bonded structure, the greater the selected pulse width, which can enhance spalling effectiveness. Laser energy plays a crucial role in determining spalling outcomes, with higher laser energy resulting in increased spalling damage. The modulation of laser energy and pulse width offers a viable approach for employing the laser shock adhesion testing in non-destructive testing of weak bonding within different material thicknesses composite material bonded structures.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112184"},"PeriodicalIF":4.6,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
In the multimode fiber laser, a phenomenon of multi-state broadband spectrum and ultra-short pulse spatiotemporal mode-locking (STML) is obtained. The dissipative soliton, multiple pulses, harmonic pulse and bound soliton can be observed by rotating the polarization controllers(PCs). The spectral bandwidth of dissipative soliton is 19.04 nm at the central wavelength of 1039.40 nm, and the pulse width is 3.58 ps, acquiring the widest spectrum and the shortest pulse in an all-fiber dissipative soliton STML laser. As the STML state changes from dissipative soliton to bound soliton, spectral bandwidth decreases slightly. The spectral width and modulation period of the loose bound soliton with central wavelength of 1038.24 nm are 18.03 nm and 0.76 nm, respectively. We realize the conversion between the multiple states, which provides a scheme for the study of nonlinear soliton dynamics.
{"title":"Multi-state broadband spectrum and ultra-short pulse spatiotemporal mode-locked Yb-doped multimode fiber laser","authors":"Haoxue Qiu, Yong Yao, Yu Yang, Linguang Guo, Songting Li, Xiaochuan Xu, Jiajun Tian, Yanfu Yang","doi":"10.1016/j.optlastec.2024.112149","DOIUrl":"10.1016/j.optlastec.2024.112149","url":null,"abstract":"<div><div>In the multimode fiber laser, a phenomenon of multi-state broadband spectrum and ultra-short pulse spatiotemporal mode-locking (STML) is obtained. The dissipative soliton, multiple pulses, harmonic pulse and bound soliton can be observed by rotating the polarization controllers(PCs). The spectral bandwidth of dissipative soliton is 19.04 nm at the central wavelength of 1039.40 nm, and the pulse width is 3.58 ps, acquiring the widest spectrum and the shortest pulse in an all-fiber dissipative soliton STML laser. As the STML state changes from dissipative soliton to bound soliton, spectral bandwidth decreases slightly. The spectral width and modulation period of the loose bound soliton with central wavelength of 1038.24 nm are 18.03 nm and 0.76 nm, respectively. We realize the conversion between the multiple states, which provides a scheme for the study of nonlinear soliton dynamics.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112149"},"PeriodicalIF":4.6,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
A comprehensive comparison illustrates the role of laser technology in altering the macro morphology and microstructure of martensitic steel joints produced by friction stir welding (FSW). In this study, laser-induced tempering (LIT) was introduced to the FSW of 1500 MPa martensitic steel. The mechanism by which LIT enhanced the mechanical properties of the FSW joints was elucidated by comparing joints produced with and without LIT. Experimental findings revealed that LIT effectively eradicated tunnel defects under the same FSW parameters. Even with an increase in travelling speed from 60 mm/min to 120 mm/min, flawless welds were achieved under LIT conditions. At 500 rpm and 60 mm/min, the bottom of the stir zone (SZ) in conventional FSW (C-FSW) joint exhibited a ferrite and martensite dual-phase microstructure. In contrast, the SZ of the LIT-FSW joint had a fully martensitic structure. Moreover, LIT resulted in significant variations in the martensitic hierarchical structure within the SZ. LIT reduced ferrite distribution in the dual-phase zone, caused recrystallized ferrite to appear further from the SZ. The stress concentration in the dual-phase zone attributed to joint fracture. The improvement in the mechanical properties of martensitic steel FSW joints was explained by analyzing the correlation between the stress concentration factor and phase fraction. Additionally, the increase in traveling speed narrowed the dual-phase zone, triggered a constraint effect that led to a maximum ultimate tensile strength (UTS) increase from 986 MPa at 60 mm/min joint to 1142 MPa at 120 mm/min joint.
{"title":"The influence of laser-induced tempering on the microstructure and mechanical properties of 1500 MPa martensitic steel friction stir welded joints","authors":"Shuhao Zhu , Xiangxiang Zhu , Wenyuan Lv , Ling Cen , Ming Gao , Yufeng Sun , Lihong Wu , Hidetoshi Fujii , Shaokang Guan","doi":"10.1016/j.optlastec.2024.112094","DOIUrl":"10.1016/j.optlastec.2024.112094","url":null,"abstract":"<div><div>A comprehensive comparison illustrates the role of laser technology in altering the macro morphology and microstructure of martensitic steel joints produced by friction stir welding (FSW). In this study, laser-induced tempering (LIT) was introduced to the FSW of 1500 MPa martensitic steel. The mechanism by which LIT enhanced the mechanical properties of the FSW joints was elucidated by comparing joints produced with and without LIT. Experimental findings revealed that LIT effectively eradicated tunnel defects under the same FSW parameters. Even with an increase in travelling speed from 60 mm/min to 120 mm/min, flawless welds were achieved under LIT conditions. At 500 rpm and 60 mm/min, the bottom of the stir zone (SZ) in conventional FSW (C-FSW) joint exhibited a ferrite and martensite dual-phase microstructure. In contrast, the SZ of the LIT-FSW joint had a fully martensitic structure. Moreover, LIT resulted in significant variations in the martensitic hierarchical structure within the SZ. LIT reduced ferrite distribution in the dual-phase zone, caused recrystallized ferrite to appear further from the SZ. The stress concentration in the dual-phase zone attributed to joint fracture. The improvement in the mechanical properties of martensitic steel FSW joints was explained by analyzing the correlation between the stress concentration factor and phase fraction. Additionally, the increase in traveling speed narrowed the dual-phase zone, triggered a constraint effect that led to a maximum ultimate tensile strength (UTS) increase from 986 MPa at 60 mm/min joint to 1142 MPa at 120 mm/min joint.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112094"},"PeriodicalIF":4.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Lasers are very powerful and can produce high temperatures, capable of melting materials when projected with an appropriate power, exposure time, distance, and beam width. High energy lasers are used for attacking enemy aircraft and missiles; however, the same threat is inevitable to the allied aircraft and missiles. Surface coatings have proven to be a viable solution to reduce damage from such laser attacks. In the present work, ZrC-Cu-based highly reflective coatings were deposited on Al-6061 alloy using the cold spray to develop laser damage resistance. Microstructural characterization, XRD, micro-hardness, reflectivity measurements, and laser ablation tests were conducted on the developed materials. The results showed improved ceramic retention and mechanical properties along with minimal porosity in the coating with increasing ZrC content in the feedstock. Additionally, the XRD analysis revealed that Cu-ZrC composite coatings could be produced by cold spray, without decarburisation of ZrC or oxidation of Cu. Owing to the exceptional purity in coatings, highly reflective coatings were obtained. At the target wavelength of 1080 nm, Cu-30 %ZrC composition achieved a remarkable reflectivity of 75 % (85 % of bulk copper). The coatings with compositions of Cu-30 %ZrC, Cu-50 %ZrC and Cu-70 %ZrC remained undamaged under laser irradiation, whereas Cu-85 %ZrC exhibited a laser ablation pit. These findings provide valuable insights into developing optimized ZrC-Cu coatings against laser irradiation.
{"title":"Highly reflective ZrC-Cu-based metal matrix composite coatings deposited via cold-spray for laser protection applications","authors":"Saiful Wali Khan , Ameey Anupam , Ekta Singla , Harpreet Singh","doi":"10.1016/j.optlastec.2024.112171","DOIUrl":"10.1016/j.optlastec.2024.112171","url":null,"abstract":"<div><div>Lasers are very powerful and can produce high temperatures, capable of melting materials when projected with an appropriate power, exposure time, distance, and beam width. High energy lasers are used for attacking enemy aircraft and missiles; however, the same threat is inevitable to the allied aircraft and missiles. Surface coatings have proven to be a viable solution to reduce damage from such laser attacks. In the present work, ZrC-Cu-based highly reflective coatings were deposited on Al-6061 alloy using the cold spray to develop laser damage resistance. Microstructural characterization, XRD, micro-hardness, reflectivity measurements, and laser ablation tests were conducted on the developed materials. The results showed improved ceramic retention and mechanical properties along with minimal porosity in the coating with increasing ZrC content in the feedstock. Additionally, the XRD analysis revealed that Cu-ZrC composite coatings could be produced by cold spray, without decarburisation of ZrC or oxidation of Cu. Owing to the exceptional purity in coatings, highly reflective coatings were obtained. At the target wavelength of 1080 nm, Cu-30 %ZrC composition achieved a remarkable reflectivity of 75 % (85 % of bulk copper). The coatings with compositions of Cu-30 %ZrC, Cu-50 %ZrC and Cu-70 %ZrC remained undamaged under laser irradiation, whereas Cu-85 %ZrC exhibited a laser ablation pit. These findings provide valuable insights into developing optimized ZrC-Cu coatings against laser irradiation.</div></div>","PeriodicalId":19511,"journal":{"name":"Optics and Laser Technology","volume":"182 ","pages":"Article 112171"},"PeriodicalIF":4.6,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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