Zhenyu Ma, Yuchen Pang, Kangquan Sun, Han Liu, Weimin Sun, Yunxiang Yan
Fiber scrambling is important in high-precision calibration systems for radial velocity measurement for searching for exoplanets. As for laser frequency combs, the modal noise of significant laser speckles can occur due to the strong coherence of the light source, which can be effectively suppressed by vibrating the fiber. However, the fibers used for scientific target detection are coupled with polychromatic light from the celestial body. This study focuses on the fiber mode noise and length dependency under white light conditions, and proposes a new fiber scrambling method of combining different types of fiber to achieve high scrambling gain. The results show that the fiber mode noise increases with decreasing length, and that there is also significant mode noise when the fiber is less than 2m, resulting in a speckle-like pattern as the modal pattern in the near field. The combination of non-circular fibers and graded index fibers can effectively reduce mode noise and improve the scrambling gain.
{"title":"Length dependency of modal noise and scrambling effect of fibers under incoherent light","authors":"Zhenyu Ma, Yuchen Pang, Kangquan Sun, Han Liu, Weimin Sun, Yunxiang Yan","doi":"10.1117/12.2687006","DOIUrl":"https://doi.org/10.1117/12.2687006","url":null,"abstract":"Fiber scrambling is important in high-precision calibration systems for radial velocity measurement for searching for exoplanets. As for laser frequency combs, the modal noise of significant laser speckles can occur due to the strong coherence of the light source, which can be effectively suppressed by vibrating the fiber. However, the fibers used for scientific target detection are coupled with polychromatic light from the celestial body. This study focuses on the fiber mode noise and length dependency under white light conditions, and proposes a new fiber scrambling method of combining different types of fiber to achieve high scrambling gain. The results show that the fiber mode noise increases with decreasing length, and that there is also significant mode noise when the fiber is less than 2m, resulting in a speckle-like pattern as the modal pattern in the near field. The combination of non-circular fibers and graded index fibers can effectively reduce mode noise and improve the scrambling gain.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"31 1","pages":"127640L - 127640L-8"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139225221","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}
Yanzhuo Hu, Lunze Hu, Liujun Yuan, Enguo Chen, Sheng Xu, Tailiang Guo, Y. Ye
In recent years, Mini-LED has been widely used in direct-lit backlight for Liquid Crystal Display (LCD) widely due to its advantages of miniaturization and low power consumption. Typical Mini-LED direct-lit backlights mainly rely on the diffuser plate to convert point-like light sources into uniform surface light sources. However, the diffuser plate cannot achieve high uniformity at a very low optical distance (OD). In this paper, we introduced the pyramidal microstructure and the semi-cylindrical microstructure to both sides of the optical film, respectively. The mechanism of influence of the pyramidal microstructure and the semi-cylindrical microstructure on light was analyzed. We clarified the relationship between the parameters of the microstructure (the pyramid angle, the pyramid dimension) and the illuminance uniformity by simulation. Moreover, two layers of microstructure optical films are discussed and simulated. Through the simulation, the optical effects are evaluated and analyzed from the point of illuminance uniformity. Simulation results maintain that when the OD is 5mm, the illuminance uniformity reaches 93.07%. Compared with the diffuser plate with a thickness of 1.5mm, the thickness is reduced by 0.9mm, and the illuminance uniformity is increased by 11.77%. This work fully demonstrates the advantages of the microstructure optical film to improve the illuminance uniformity.
{"title":"Design of microstructure optical film for high uniform mini-LED backlight","authors":"Yanzhuo Hu, Lunze Hu, Liujun Yuan, Enguo Chen, Sheng Xu, Tailiang Guo, Y. Ye","doi":"10.1117/12.2689049","DOIUrl":"https://doi.org/10.1117/12.2689049","url":null,"abstract":"In recent years, Mini-LED has been widely used in direct-lit backlight for Liquid Crystal Display (LCD) widely due to its advantages of miniaturization and low power consumption. Typical Mini-LED direct-lit backlights mainly rely on the diffuser plate to convert point-like light sources into uniform surface light sources. However, the diffuser plate cannot achieve high uniformity at a very low optical distance (OD). In this paper, we introduced the pyramidal microstructure and the semi-cylindrical microstructure to both sides of the optical film, respectively. The mechanism of influence of the pyramidal microstructure and the semi-cylindrical microstructure on light was analyzed. We clarified the relationship between the parameters of the microstructure (the pyramid angle, the pyramid dimension) and the illuminance uniformity by simulation. Moreover, two layers of microstructure optical films are discussed and simulated. Through the simulation, the optical effects are evaluated and analyzed from the point of illuminance uniformity. Simulation results maintain that when the OD is 5mm, the illuminance uniformity reaches 93.07%. Compared with the diffuser plate with a thickness of 1.5mm, the thickness is reduced by 0.9mm, and the illuminance uniformity is increased by 11.77%. This work fully demonstrates the advantages of the microstructure optical film to improve the illuminance uniformity.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"28 1","pages":"127650B - 127650B-7"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139225517","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}
Electronic information systems are highly sensitive to electromagnetic signals, rendering them vulnerable to electromagnetic weapon attacks. The presence of metal electrodes and wires in these systems prevents them from being immune to attacks from electromagnetic weapons. This study specifically focuses on enhancing the RF signal receiving front-end, comprising a lithium niobate modulation chip and a full dielectric antenna. We utilized the finite-difference time-domain (FDTD) method to simulate and optimize the chip structure of the lithium niobate waveguide. Based on the optimization results, a two-step etching process was employed to fabricate the chip. The micro-ring in the Ku-band photonic RF front-end has been experimentally measured to possess a Q-factor of 74,000, with an instantaneous bandwidth of 2.5 GHz. This research holds significant implications for safeguarding electronic information systems against the potential damage caused by electromagnetic forces.
{"title":"Research on electrode-free RF receiver front-end based on lithium niobate photonic chip","authors":"Shaoshuai Han, Yangyang Yu, Mingxiang Yang, Mengting Ning, Zhenlin Wu","doi":"10.1117/12.2687952","DOIUrl":"https://doi.org/10.1117/12.2687952","url":null,"abstract":"Electronic information systems are highly sensitive to electromagnetic signals, rendering them vulnerable to electromagnetic weapon attacks. The presence of metal electrodes and wires in these systems prevents them from being immune to attacks from electromagnetic weapons. This study specifically focuses on enhancing the RF signal receiving front-end, comprising a lithium niobate modulation chip and a full dielectric antenna. We utilized the finite-difference time-domain (FDTD) method to simulate and optimize the chip structure of the lithium niobate waveguide. Based on the optimization results, a two-step etching process was employed to fabricate the chip. The micro-ring in the Ku-band photonic RF front-end has been experimentally measured to possess a Q-factor of 74,000, with an instantaneous bandwidth of 2.5 GHz. This research holds significant implications for safeguarding electronic information systems against the potential damage caused by electromagnetic forces.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"53 1","pages":"127720A - 127720A-7"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139226469","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}
Pulsed laser processing matures as a powerful technique for flexible and high-performing nanostructuration. Rich physics behind the light-matter interaction allows to produce unique surface nanotextures with desired properties, beneficial for various practically-relevant applications such as optical sensing, anti-counterfeiting, realization of nanophotonic platforms and so on. Here we have applied direct femtosecond-laser printing to locally fabricate nanostructures on glass-supported amorphous-silicon thin film for realization of high-resolution (up to 60 000 dots per inch) security labels offering full-optical information encryption in several ways. Since the proposed tag represents array of close-packed amorphous-silicon hemispherical nanoparticles, the first approach for information encryption is to selectively crystallize some of nanoparticles by continuous-wave laser irradiation without morphological changes. Thus, crystalized nanoparticles ordered in a user-defined way indicate encrypted information that can be read using Raman signal intensity mapping at frequency of 519 cm−1, corresponding to the main phonon mode of crystalline silicon. The second way is to hide Mie-resonant nanoparticles between non-resonant ones. Since the latter haven’t proper size to resonantly interact with pump radiation during Raman signal mapping, encrypted information can be revealed via evident variation in Raman yield between resonant and non-resonant nanoparticles. Thereby, we demonstrated facile single step printing of anti-counterfeiting labels at resolution up to 60 000 dots per inch justifying the applicability of the developed approach for optical information encryption.
{"title":"Femtosecond-laser nanostructuring of silicon thin films for optical information encryption","authors":"Sergey A. Syubaev","doi":"10.1117/12.2688543","DOIUrl":"https://doi.org/10.1117/12.2688543","url":null,"abstract":"Pulsed laser processing matures as a powerful technique for flexible and high-performing nanostructuration. Rich physics behind the light-matter interaction allows to produce unique surface nanotextures with desired properties, beneficial for various practically-relevant applications such as optical sensing, anti-counterfeiting, realization of nanophotonic platforms and so on. Here we have applied direct femtosecond-laser printing to locally fabricate nanostructures on glass-supported amorphous-silicon thin film for realization of high-resolution (up to 60 000 dots per inch) security labels offering full-optical information encryption in several ways. Since the proposed tag represents array of close-packed amorphous-silicon hemispherical nanoparticles, the first approach for information encryption is to selectively crystallize some of nanoparticles by continuous-wave laser irradiation without morphological changes. Thus, crystalized nanoparticles ordered in a user-defined way indicate encrypted information that can be read using Raman signal intensity mapping at frequency of 519 cm−1, corresponding to the main phonon mode of crystalline silicon. The second way is to hide Mie-resonant nanoparticles between non-resonant ones. Since the latter haven’t proper size to resonantly interact with pump radiation during Raman signal mapping, encrypted information can be revealed via evident variation in Raman yield between resonant and non-resonant nanoparticles. Thereby, we demonstrated facile single step printing of anti-counterfeiting labels at resolution up to 60 000 dots per inch justifying the applicability of the developed approach for optical information encryption.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"120 1","pages":"127730J - 127730J-9"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139226840","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}
Vortex beams that carry orbital angular momentum (OAM) have garnered significant attention, as they bring the degree of freedom of OAM to modern optical communication, beyond the traditional degrees of freedom such as amplitude, phase and polarization. Meanwhile, metasurfaces composed of ultra-thin layers of subwavelength structures have also been utilized for light manipulation. Nevertheless, the combination of these two concepts has not been explored in the form of microring resonator-based light emitter. In this work, we demonstrate a Si-based, passive, conjugate symmetrybreaking emitter in numerical simulation. This broken conjugate symmetry enables the emitter to generate OAMs with different topological charges, when it is driven at two opposite input directions.
{"title":"Metasurface-integrated microring resonators for off-chip vortex beam generation","authors":"Jian-Tzung Huang, Wangke Yu, Zihang Zheng, Jize Yan, Xu Fang","doi":"10.1117/12.2689032","DOIUrl":"https://doi.org/10.1117/12.2689032","url":null,"abstract":"Vortex beams that carry orbital angular momentum (OAM) have garnered significant attention, as they bring the degree of freedom of OAM to modern optical communication, beyond the traditional degrees of freedom such as amplitude, phase and polarization. Meanwhile, metasurfaces composed of ultra-thin layers of subwavelength structures have also been utilized for light manipulation. Nevertheless, the combination of these two concepts has not been explored in the form of microring resonator-based light emitter. In this work, we demonstrate a Si-based, passive, conjugate symmetrybreaking emitter in numerical simulation. This broken conjugate symmetry enables the emitter to generate OAMs with different topological charges, when it is driven at two opposite input directions.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"61 1","pages":"127730F - 127730F-5"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139227412","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}
Wu Fei, Lu Chen, Wei Qiu, Liangkun Dai, Xiaoyun Jiang, Yuwei Fang, Youlong Yu, Qiwen Zhan, Jigang Hu
Here we propose a metasurface consisting of asymmetric dielectric tetramer arrays, which can realize a polarization-sensitive light modulation through toroidal dipole resonance (TDR) in the near-infrared (NIR) region. We found, by breaking the C4v symmetry of the tetramer arrays, two narrow-band TDRs can be created with the linewidth around 1.5 nm. Multipolar decomposition of scattering power and electromagnetic field distribution calculations confirm the excitation of TDRs. Our simulation results show that 100% modulation depth in light absorption and selective field confinement can be achieved by changing the polarization orientation of the incident light. Our findings will prompt versatile applications in optical switching, storage, polarization detection, and light emitting devices.
{"title":"Polarization-sensitive optical absorption modulation driven by toroidal-dipole resonance in asymmetric dielectric tetramer metasurface","authors":"Wu Fei, Lu Chen, Wei Qiu, Liangkun Dai, Xiaoyun Jiang, Yuwei Fang, Youlong Yu, Qiwen Zhan, Jigang Hu","doi":"10.1117/12.2686633","DOIUrl":"https://doi.org/10.1117/12.2686633","url":null,"abstract":"Here we propose a metasurface consisting of asymmetric dielectric tetramer arrays, which can realize a polarization-sensitive light modulation through toroidal dipole resonance (TDR) in the near-infrared (NIR) region. We found, by breaking the C4v symmetry of the tetramer arrays, two narrow-band TDRs can be created with the linewidth around 1.5 nm. Multipolar decomposition of scattering power and electromagnetic field distribution calculations confirm the excitation of TDRs. Our simulation results show that 100% modulation depth in light absorption and selective field confinement can be achieved by changing the polarization orientation of the incident light. Our findings will prompt versatile applications in optical switching, storage, polarization detection, and light emitting devices.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"21 1","pages":"1277308 - 1277308-6"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139218311","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}
Haoran Li, Haisong Tang, Zexin Feng, Yi Luo, Yongtian Wang
We previously optimized the freeform surfaces using extended polynomials in stereographic projection coordinates based on an automated workflow linking the optimization engine, 3D modeling software and ray tracing software [Optics Express 29(9), 13469–13485 (2021)]. However, this method is time consuming as it needs thousands of irradiance evaluations. Here, we speed up the optimization of spherical-freeform lenses for uniform illumination based on differentiable ray tracing. The freeform surface is still parameterized with the ‘uv’ extended polynomials under stereographic projection coordinates, which is suitable for generating simple illumination patterns. We implement differentiable ray tracing based on computation graph in MindSpore framework, which is efficient and effective by calculating derivatives of the surface parameters during a single backpropagation. We provide two design examples for generating uniform irradiance distributions with a point-like source and an extended light source, respectively.
{"title":"Spherical-freeform lens design for uniform illumination based on differentiable ray tracing with uv polynomials","authors":"Haoran Li, Haisong Tang, Zexin Feng, Yi Luo, Yongtian Wang","doi":"10.1117/12.2687294","DOIUrl":"https://doi.org/10.1117/12.2687294","url":null,"abstract":"We previously optimized the freeform surfaces using extended polynomials in stereographic projection coordinates based on an automated workflow linking the optimization engine, 3D modeling software and ray tracing software [Optics Express 29(9), 13469–13485 (2021)]. However, this method is time consuming as it needs thousands of irradiance evaluations. Here, we speed up the optimization of spherical-freeform lenses for uniform illumination based on differentiable ray tracing. The freeform surface is still parameterized with the ‘uv’ extended polynomials under stereographic projection coordinates, which is suitable for generating simple illumination patterns. We implement differentiable ray tracing based on computation graph in MindSpore framework, which is efficient and effective by calculating derivatives of the surface parameters during a single backpropagation. We provide two design examples for generating uniform irradiance distributions with a point-like source and an extended light source, respectively.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"49 1","pages":"127650H - 127650H-7"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139219045","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}
N. Kondratiev, Marcus Engsig, Evgeny Lonshakov, C. Kasmi, S. Cordette
Optical array antennas have diverse applications in optical communication, remote sensing, imaging, and astronomy, supporting a broad range of optical and photonics-based technologies. Traditional square phased array antennas require a half-wavelength emitter spacing to prevent secondary orders of emission (aliasing). However, achieving such small distances in optics is impractical. To break this limitation irregularly-placed arrays has been proposed. This study focuses on the alias-free spiral array, which allows for high level of sidelobe suppression. Using standard Huygens–Fresnel principle approach to calculate the emission pattern, we identify key parameters of the spiral and consider their influence on the result. We perform multi-parametric optimisation of the spiral array for maximum suppression of sidelobes, enhancing its performance by dB compared to previously suggested bio-inspired design. This research provides insights into overcoming aliasing challenges and improving the efficiency of optical array antennas.
{"title":"Side lobe suppression analysis of spiral array optical antenna","authors":"N. Kondratiev, Marcus Engsig, Evgeny Lonshakov, C. Kasmi, S. Cordette","doi":"10.1117/12.2687176","DOIUrl":"https://doi.org/10.1117/12.2687176","url":null,"abstract":"Optical array antennas have diverse applications in optical communication, remote sensing, imaging, and astronomy, supporting a broad range of optical and photonics-based technologies. Traditional square phased array antennas require a half-wavelength emitter spacing to prevent secondary orders of emission (aliasing). However, achieving such small distances in optics is impractical. To break this limitation irregularly-placed arrays has been proposed. This study focuses on the alias-free spiral array, which allows for high level of sidelobe suppression. Using standard Huygens–Fresnel principle approach to calculate the emission pattern, we identify key parameters of the spiral and consider their influence on the result. We perform multi-parametric optimisation of the spiral array for maximum suppression of sidelobes, enhancing its performance by dB compared to previously suggested bio-inspired design. This research provides insights into overcoming aliasing challenges and improving the efficiency of optical array antennas.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"23 1","pages":"127640T - 127640T-7"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139222154","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}
Zichen Wang, Yao Hu, Qun Hao, Chuheng Xu, YuanHeng Liu
Transient measurement technology has broad application prospects in fields such as mirror processing, automotive painting, and precision mechanical processing. It can help us monitor and analyze instantaneous changes in the processing process in real-time. The existing contact and non-contact measurement methods have drawbacks in both non-destructive testing and transient measurement directions. This paper develops a transient measurement system for color speckle deflectometry, aiming to improve efficiency in the field of optical measurement. The core components of the system described in this paper include a liquid crystal display (LCD) screen, a camera, and a beam splitter. By using multi-channel speckle fusion and color correction, one color image is captured to achieve the same effect as the previous three monochromatic images. The gradient of each point on the surface under test (SUT) is obtained through speckle shift, and then the surface shape of the SUT is obtained through integration. The feasibility is verified by the actual measurement with a flat mirror. By utilizing these devices and methods, transient measurement of the three-dimensional shape of a mirror can be achieved, and reliable results can be obtained in both laboratory environments and processing sites. Compared with traditional measurement methods, this system not only has a significant improvement in measurement speed, but also can achieve non-destructive and in place measurement.
瞬态测量技术在镜面加工、汽车喷漆和精密机械加工等领域有着广阔的应用前景。它可以帮助我们实时监控和分析加工过程中的瞬时变化。现有的接触式和非接触式测量方法在无损检测和瞬态测量两个方向上都存在缺陷。本文开发了一种用于彩色斑点偏转测量的瞬态测量系统，旨在提高光学测量领域的效率。本文所述系统的核心部件包括液晶显示屏（LCD）、摄像头和分光镜。通过使用多通道斑点融合和色彩校正，可以捕捉到一幅彩色图像，达到与前三幅单色图像相同的效果。通过斑点移动获得被测表面（SUT）上每个点的梯度，然后通过积分获得 SUT 的表面形状。通过使用平面镜进行实际测量来验证其可行性。利用这些装置和方法，可以实现镜面三维形状的瞬态测量，并可在实验室环境和加工现场获得可靠的结果。与传统的测量方法相比，该系统不仅在测量速度上有显著提高，而且还能实现无损和就地测量。
{"title":"Color speckle deflectometry for three-dimensional surface transient measurement","authors":"Zichen Wang, Yao Hu, Qun Hao, Chuheng Xu, YuanHeng Liu","doi":"10.1117/12.2686390","DOIUrl":"https://doi.org/10.1117/12.2686390","url":null,"abstract":"Transient measurement technology has broad application prospects in fields such as mirror processing, automotive painting, and precision mechanical processing. It can help us monitor and analyze instantaneous changes in the processing process in real-time. The existing contact and non-contact measurement methods have drawbacks in both non-destructive testing and transient measurement directions. This paper develops a transient measurement system for color speckle deflectometry, aiming to improve efficiency in the field of optical measurement. The core components of the system described in this paper include a liquid crystal display (LCD) screen, a camera, and a beam splitter. By using multi-channel speckle fusion and color correction, one color image is captured to achieve the same effect as the previous three monochromatic images. The gradient of each point on the surface under test (SUT) is obtained through speckle shift, and then the surface shape of the SUT is obtained through integration. The feasibility is verified by the actual measurement with a flat mirror. By utilizing these devices and methods, transient measurement of the three-dimensional shape of a mirror can be achieved, and reliable results can be obtained in both laboratory environments and processing sites. Compared with traditional measurement methods, this system not only has a significant improvement in measurement speed, but also can achieve non-destructive and in place measurement.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"31 1","pages":"127650Q - 127650Q-8"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139224762","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}
Jiajing Cao, Jun Chang, Junya Wang, Bingqing Xie, Dongmei Li
Off-axis reflective zoom imaging optical system has a wide range of applications in the field of photoelectric detection because of its advantages of chromatic aberration-free, broad-spectrum imaging. The existing off-axis reflective zoom imaging optical system has a fixed pupil diameter, and as the focal length becomes larger, the relative aperture becomes smaller, resulting in a lower signal-to-noise ratio and weaker detection capability. Additionally, aberration correction is vitally important in the off-axis reflective zoom system with large relative aperture. An attempt to improve the performance of an off-axis reflective zoom imaging system with large relative aperture using freeform surface is reported. The F number is 4, and the zoom ratio is 3. The optical design with freeform surfaces shows marked improvements compared with the design with higher order aspheric surfaces.
{"title":"Optical design of off-axis freeform reflective zoom imaging system with large relative aperture","authors":"Jiajing Cao, Jun Chang, Junya Wang, Bingqing Xie, Dongmei Li","doi":"10.1117/12.2685883","DOIUrl":"https://doi.org/10.1117/12.2685883","url":null,"abstract":"Off-axis reflective zoom imaging optical system has a wide range of applications in the field of photoelectric detection because of its advantages of chromatic aberration-free, broad-spectrum imaging. The existing off-axis reflective zoom imaging optical system has a fixed pupil diameter, and as the focal length becomes larger, the relative aperture becomes smaller, resulting in a lower signal-to-noise ratio and weaker detection capability. Additionally, aberration correction is vitally important in the off-axis reflective zoom system with large relative aperture. An attempt to improve the performance of an off-axis reflective zoom imaging system with large relative aperture using freeform surface is reported. The F number is 4, and the zoom ratio is 3. The optical design with freeform surfaces shows marked improvements compared with the design with higher order aspheric surfaces.","PeriodicalId":149506,"journal":{"name":"SPIE/COS Photonics Asia","volume":"250 1","pages":"127650E - 127650E-8"},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139227854","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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