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Reconfigurable metasurface lens based on graphene split ring resonators using Pancharatnam–Berry phase manipulation
摘要： A reconfigurable graphene based metasurface is presented to controllably focus a circularly polarized incident plane wave. The unit cell of the proposed metasurface consists of split ring resonators on both sides of a dielectric layer. The required phase shift for focusing purpose is achieved by concurrent rotation of the elements to obey to the Pancharatnam–Berry concept. Convergence/Divergence of the transmitted wave can be controlled by handedness of the impinging plane wave and direction of the elements’ rotation. The operating frequency of the designed lens and its focal length can be adjusted by properly exploiting to the unique property of graphene, i.e. by tuning its chemical potential.
关键词： metasurface,Graphene,Pancharatnam–Berry phase,reconfigurable lens
更新于2025-09-23 15:23:52
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Monodimensional enlargement of resolved field of view in line scan cameras by a single doubly symmetric mirror
摘要： The geometry of the sensed and thus optically relevant area in the image plane of line scan cameras suggests that improvement of the overall system is possible, by joint design of optics and electronics. By a technique named Linear Fovea (LF) proposed in this paper, the optical contrast along the Line-of-Interest (LOI) in the image plane i.e. the location of the opto-electronic sensor, is optimized at the expense of contrast elsewhere. In the LF method, employing a single doubly symmetric surface, the resolved ?eld of view (RFOV) as the merit function, is maximized, by ?nding appropriate Zernike coe?cients describing that surface. The technique is applied on a proof-of-concept single mirror telescope and both MTF analysis and standard target imaging simulation are performed. Results show that by this technique, the RFOV can be doubled, or alternatively the illumination can be increased 2.5 times keeping RFOV unchanged. Furthermore, a rather uniform response is kept along the LOI.
关键词： Foveated imaging,Aberration compensation,Lens design,Wide ?eld angle lenses,Free form optics,Line scan cameras
更新于2025-09-23 15:23:52
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Anti-detection technology of cat eye target based on decentered field lens
摘要： Optoelectronic imaging equipment is easy to expose to active laser detection devices because of 'cat eye' effect. In this paper, we propose a new structure of optical system to reduce the retrore?ector effect of a cat eye target. Decentered ?eld lens structure is adopted in the design without sacri?cing imaging quality and clear aperture. An imaging system with ±30? ?eld of view is taken for example. The detailed design and simulation results are presented. The results indicate that this kind of optical system can reduce the retrore?ection signal substantially and maintain acceptable imaging performance.
关键词： decentered ?eld lens,cat eye effect reduction,geometric optical design
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Chongqing (2018.6.27-2018.6.29)] 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Research on Single-Frame Super-Resolution Reconstruction Algorithm for Low Resolution Cell Images Based on Convolutional Neural Network
摘要： At the problem of low resolution and low contrast of cell images collected by lens-less cell imaging system, a novel cell super-resolution reconstruction network (CSRN) based on convolutional neural network is proposed. First, the cell image is collected by lens-less cell imaging system, and then the cell image is down-sampled by bicubic interpolation to obtain low-resolution cell image. Then, the low-resolution cell image is input into the CSRN network for super-resolution reconstruction. The experimental results show that the proposed CSRN network can effectively improve the resolution and contrast of cell images, and the reconstruction effect is better than that of the traditional bicubic interpolation and SRCNN network.
关键词： convolutional neural network,cell image,super-resolution,lens-less imaging
更新于2025-09-23 15:23:52
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Design of a Broadband Metasurface Luneburg Lens for Full-Angle Operation
摘要： We present a broadband metasurface Luneburg lens for full-angle operation. The design of the Luneburg lens is based on an inverted substrate parallel-plate-waveguide structure with nonuniform circular holes etched on the upper metallic plate. We show that this structure is superior to existing designs as it allows significant simplification of the fabrication process. To achieve a smooth variation of the effective refractive index profile as well as circular symmetry for the Luneburg lens, size-variable meta atoms are used for synthesizing the metasurface. The effective refractive index profile can be tuned by varying just the hole diameters. By introducing tapered microstrip ports that are evenly distributed on the circumference of the Luneburg lens, full-angle operation of the lens can be achieved. A prototype with a diameter of 400 mm is fabricated and experimentally evaluated at operating frequencies ranging from 6 GHz to 9 GHz. We show good conceptual agreement between simulated and experimental results.
关键词： metasurface,inverted substrate parallel-plate-waveguide,Luneburg lens,Full-angle operation
更新于2025-09-23 15:23:52
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Dual functional optofluidic platform based on light-actuated air plug
摘要： Optical systems based on fluid-fluid interface are gaining great attention because they offer added advantages such as dynamic, reconfigurable, and self-healing capabilities with less complex fabrication steps compared to the solid based optical elements. Moreover, cost-effectiveness and ease of miniaturization pave a potential route towards the realization of portable optical and optofluidic devices. However, a single optofluidic device having remotely controlled multifunctional capabilities remains a challenge. We demonstrate an optofluidic multifunctional strategy, which could operate either as an optical switch or a tunable liquid lens. The principle relies on light-controlled volumetric change of an air plug confined in a minichannel filled with water. For the optical switch, volumetric change of the air plug modulates total internal reflection. A temperature difference of only 0.2 °C is sufficient for a subsecond switching time (0.6 ± 0.1 s). For the liquid lens, the change of plug size acts as an actuator to control the meniscus shape of the liquid. Upon heating or cooling, the meniscus develops a convex or a concave lens respectively. A temperature difference of 0.1–0.7 °C is sufficient for realizing tunability in the focal length. The demonstrated strategy is simple, cost-effective, non-contact and the device could be operated at room temperature.
关键词： Optical switch,Total internal reflection,Liquid lens
更新于2025-09-23 15:23:52
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Light in power
摘要： We present in this paper a generic and parameter-free algorithm to efficiently build a wide variety of optical components, such as mirrors or lenses, that satisfy some light energy constraints. In all of our problems, one is given a collimated or point light source and a desired illumination after reflection or refraction and the goal is to design the geometry of a mirror or lens which transports exactly the light emitted by the source onto the target. We first propose a general framework and show that eight different optical component design problems amount to solving a light energy conservation equation that involves the computation of visibility diagrams. We then show that these diagrams all have the same structure and can be obtained by intersecting a 3D Power diagram with a planar or spherical domain. This allows us to propose an efficient and fully generic algorithm capable to solve these eight optical component design problems. The support of the prescribed target illumination can be a set of directions or a set of points located at a finite distance. Our solutions satisfy design constraints such as convexity or concavity. We show the effectiveness of our algorithm on simulated and fabricated examples.
关键词： Mirror design,Caustics,Lens design,Power diagram,Optimal Transport,Non-imaging Optics
更新于2025-09-23 15:23:52
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Aberrated Microlenses to Reduce Crosstalk in Free Space Optical Interconnects Systems
摘要： A free space optical interconnects system that uses Gaussian beams and focusing microlenses with spherical aberration has been considered. Numerical results show that the use of microlenses with negative spherical improves the signal-to-crosstalk ratio of the interconnects system at some optimum positions of the detector array. An expression for output field at the detectors plane is derived and used to evaluate the signal-to-crosstalk ratio.
关键词： lens spherical aberration,optical crosstalk,free space optical interconnects
更新于2025-09-23 15:23:52
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Resultados visuales, independencia de gafas e insatisfacción tras implante de una lente intraocular difractiva trifocal
摘要： Purpose: To investigate visual outcomes, spectacle independence, and patient satisfaction after trifocal intraocular lens implantation. Methods: A retrospective study conducted on 5,186 patients who underwent phacoemulsification and were implanted with a diffractive trifocal intraocular lens (FineVision Micro F, PhysIOL SA, Liège, Belgium). Results: The mean pre-operative keratometry was 43.61 ± 1.55 D, and mean keratometric cylinder was -0.86 ± 0.66 D. At 3 months post-operatively, values changed to 43.59 ± 1.56 and -0.71 ± 0.46 D, respectively. Mean sphere varied from 2.04 ± 2.60 to 0.14 ± 0.38 D, and mean spherical equivalent from 1.64 ± 2.61 to -0.05 ± 0.36 D. More than 60% of the patients achieved better corrected distance visual acuity. The majority had a final residual refractive error (predictability) lower than 1 D (99.1%), with 14.3% needing optical adjustment (bioptics). Posterior capsulotomy was performed in 2.2%, and the lens was replaced in 5 patients. A high percentage of patients were satisfied in terms of vision and spectacle independence at all distances. Although 2% referred to worsening of night vision quality, only 2% were not very satisfied and 20 patients were dissatisfied. The causes were: blurred vision (7 cases), spectacle dependence (10), dysphotopsia (7), and dry eye (4). Conclusions: The implantation of this model provided good visual performance in all distances, as well as high levels of spectacle independence and satisfaction.
关键词： Trifocal,Intraocular lens,Multifocal,Dissatisfaction,Satisfaction
更新于2025-09-23 15:23:52
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Spectroscopy of Oxygen-Sensitive Material for Measuring Contact Lens Oxygen Transmissibility
摘要： Purpose: Oxygen permeability or transmissibility is a crucial parameter for contact lenses to ensure that extended wear will not induce corneal hypoxia. This work tests a new method of using the oxidation of cysteamine, an oxygen-sensitive chemical, to quantify the oxygen transmissibility of current commercial contact lenses and contact lenses loaded with vitamin E. Methods: 3D printing was used to modify eye drop bottles and quartz cuvettes to create systems that allowed insertion of a contact lens in between the cysteamine solution and air. Both systems were exposed to atmospheric conditions where the only path of entry for oxygen was through the contact lens. The entering oxygen reacted with cysteamine, and the rate of cysteamine oxidation was measured using UV-vis spectrophotometry. The rate was then stoichiometrically related to oxygen transmissibility. Results: The eye drop method predicted transmissibility values within 9% of established, commercial values. The cuvette method predicted values within 10% of established values for silicone hydrogel lenses without any correction factor and within 11% for poly-hydroxyethyl-methacrylate lenses after correcting for oxygen entering the system. Incorporation of 20% (w/w) vitamin E into Acuvue? Oasys? lenses did not have a significant impact on the oxygen transmissibility. Conclusions: Both methods presented in this work can reliably measure oxygen transmissibility of contacts lenses or other materials. Further improvements in manufacturing could lead to improved accuracy and reliability, allowing wider use of this method for quantifying the oxygen transport in contact lenses.
关键词： oxidation,oxygen permeability,spectrophotometry,3D printing,contact lens
更新于2025-09-23 15:23:52