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- 摘要
- 关键词
- 实验方案
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Optronic High-Resolution SAR Processing with the Capability of Full-Resolution Imaging
摘要： The improvement of synthetic aperture radar (SAR) resolution brings a broader applications but poses a great burden for SAR data processor. Real-time processing becomes a difficulty. Optronic technology has been developed for SAR real-time processing due to its ultrafast processing speed. A novel real-time optronic high-resolution SAR processor is proposed in this paper. It has the capability of full-resolution imaging. Restricted with the data scale of spatial light modulators (SLMs), SAR raw data cannot be all encoded onto the light beams at a time. To solve this, subaperture architecture is introduced in our system scheme. SAR data is optically processed in parallel by multiple optical subaperture processing modules and synthesized into a full-resolution SAR image. The module is implemented by multiple SLMs and lenses, which is innovatively proposed in this paper. The proposed system is applicable to large-scale SAR data processing, and the data scale is easy to extend with implementation of adding identical optical subaperture processing modules. Airborne SAR real data is used in the experiment, and a high-resolution image is also given. The PSLR of the focus results with and without subaperture partition are analyzed, which validate the satisfying image quality of the proposed algorithm.
关键词： high resolution,synthetic aperture radar,spatial light modulator,subaperture,full-resolution imaging,Optronic processing
更新于2025-09-23 15:22:29
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The application of SLM in shearography detecting system
摘要： The paper presents a new shearography system which applies a spatial light modulator (SLM). The system can control the shearing amount and direction as well as introduce the phase shift accurately and automatically, making shearographic testing easier and more practical. Shearography has the known advantages for nondestructive test and strain measurements of being fast, full-field, and having high sensitivity. Traditionally, the shearing amount is controlled by adjusting a reflector mechanically. Mechanical adjustment of the reflector is slow, inconvenient and not well suited for in-field NDT practice. For application of phase shift techniques, a piezoelectric transducer (PZT), which is usually used for application of phase shift techniques, introduces random error due to its tendency to be nonlinear. This paper introduces a new shearographic detection system with a spatial light modulator. The spatial light modulator controls the liquid crystal by using a birefringence effect and twisted nematic effect. The spatial light modulator can change the phase of the light and shearing amount accurately and automatically, thus eliminating the nonlinear random error in the phase shift method. Furthermore, this system also improves testing efficiency. In this paper, the fundamental of SLM shearography is presented. The capability of this optical configuration is demonstrated theoretically as well as through experiments.
关键词： Nondestructive detecting,Spatial light modulator,Shearography,Phase series
更新于2025-09-23 15:22:29
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High-resolution refractometry using phase shifting interferometry based on spatial light modulator and vortex probe
摘要： We present a spatial light modulator (SLM) based phase shifting interferometry (PSI) using an optical vortex for sensing the refractive index (RI) of liquids. The vortex phase rotates according to the phase shift introduced by a medium, and its rotation angle quantifies the index of refraction of the sample. An interferometer modified with the SLM is designed to obtain reliable results. We experimentally demonstrate the stability of the SLM-based system by measuring interference and phase fluctuation. Experimental results show that the proposed system keeps the fluctuation small. The vortex probe PSI combined with the SLM-based interferometer enables not only detecting extremely small changes in concentration but also precisely measuring the RI with high resolution of ～10?? refractive index unit.
关键词： Refractive index sensing,Spatial light modulator,Optical vortex,Interferometry
更新于2025-09-23 15:22:29
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Holographic Fabrication and Optical Property of Graded Photonic Super-Crystals with a Rectangular Unit Super-Cell
摘要： Recently developed graded photonic super-crystals show an enhanced light absorption and light extraction efficiency if they are integrated with a solar cell and an organic light emitting device, respectively. In this paper, we present the holographic fabrication of a graded photonic super-crystal with a rectangular unit super-cell. The spatial light modulator-based pixel-by-pixel phase engineering of the incident laser beam provides a high resolution phase pattern for interference lithography. This also provides a flexible design for the graded photonic super-crystals with a different ratio of length over the width of the rectangular unit super-cell. The light extraction efficiency is simulated for the organic light emitting device, where the cathode is patterned with the graded photonic super-crystal. The high extraction efficiency is maintained for different exposure thresholds during the interference lithography. The desired polarization effects are observed for certain exposure thresholds. The extraction efficiency reaches as high as 75% in the glass substrate.
关键词： spatial light modulator,holographic lithography,organic light emitting device,photonic crystals,graded photonic super-crystals,extraction efficiency
更新于2025-09-23 15:21:01
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Fabrication of oila??water separation copper filter by spatial light modulated femtosecond laser
摘要： Surface with oil-water separation performance has attracted more and more attention in the application of oil-containing wastewater purification. Much related work has been done by many researchers. However, there are still many difficulties in rapid manufacturing of filter membranes with special wettability. In this paper, an efficient, flexible method to fabricate microporous arrays by using femtosecond (fs) laser combined with spatial light modulator (SLM) is proposed. The laser treated copper sheet surface shows hydrophobic and superoleophilic properties due to the microstructure. Meanwhile, the array of micro-through-holes on the surface can allow oil to penetrate through holes and prevent water from penetrating. The manufacturing process is not only extremely efficient, 10×10 focus array are used in the ablation, but also it is without chemical method and the filter presents a long-term stable hydrophobic and superoleophilic performance.
关键词： Superoleophilic,Oil-water separation,Hydrophobic,Spatial light modulator,Femtosecond laser
更新于2025-09-23 15:21:01
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Multispectral Management of the Photon Orbital Angular Momentum
摘要： We report on a programmable liquid crystal spatial light modulator enabling independent orbital angular momentum state control on multiple spectral channels. This is done by using electrically controllable “topological pixels" that independently behave as geometric phase micro-optical elements relying on self-engineered liquid crystal defects. These results open interesting opportunities in optical manipulation, sensing, imaging, and communications, as well as information processing. In particular, spectral vortex modulation allows considering singular spatiotemporal shaping of ultrashort pulses which may find applications in many areas such as material processing, spectroscopy, or elementary particles acceleration.
关键词： liquid crystal spatial light modulator,spectral vortex modulation,photon orbital angular momentum,geometric phase micro-optical elements,ultrashort pulses
更新于2025-09-23 15:21:01
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A remote laser focusing system with spatial light modulator
摘要： This paper designs a remote laser focusing system (RLFS) based on spatial light modulator (SLM). In this system, the SLM serves as an active optical element that modulates the wavefront of the laser beam, causing variation in beam transmission. Theoretical analysis shows that a reflective SLM can compensate the residual aberrations at different operating distances, enabling the accurate focusing of targets without sacrificing the energy convergence. Based on optical design software, the geometrical parameters were optimized for the presented system through simulation. Finally, experimental demonstration and error analysis were carried out. The results show that the proposed RLFS-SLM is more stable and capable for controlling energy convergence than the traditional mechanical RLFS. Our system provides a desirable tool for high-energy laser applications.
关键词： Remote laser focusing (RLF),Wavefront modulation,Spatial light modulator (SLM),Mechanical focusing
更新于2025-09-23 15:19:57
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A V-Folded Digital Laser for On-Demand Vortex Beams by Astigmatic Transformation of Hermitea??Gaussian Modes <sup>*</sup>
摘要： A V-folded digital laser using a spatial light modulator (SLM) for intra-cavity loss shaping is exploited to generate Hermite–Gaussian modes with on-demand mode order. With a ??/2 astigmatic mode converter, vortex beams carrying on-demand orbital angular momentum (OAM) with a tunable range from ?11(cid:126) to 12(cid:126) are obtained. The mode order of the HG mode, hence the OAM of the vortex beam, is digitally switched by changing the phase pattern imposed on the SLM without requiring any mechanic alignment of the cavity. This work has great potential applications in various OAM-tunable vortex beams.
关键词： spatial light modulator,vortex beams,orbital angular momentum,Hermite–Gaussian modes,digital laser
更新于2025-09-23 15:19:57
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8.3: <i>Invited Paper:</i> Ultra High Resolution Display for Digital Holography
摘要： Ultra high resolution display panels are one of the technical trends for future display and essential for the realization of digital hologram. Two approaches for the development toward 1um pixel pitch are introduced. SLM panel with 3μm pixel pitch based on reflected TFT-LCD was fabricated. Reconstructed hologram images were successfully demonstrated. SLM based on phase change materials was under development. In this case the driving circuitry was consist of Si CMOS backplane. Due to the scalability of PCM materials, accomplishment of pixel pitch with 1μm is very promising.
关键词： TFT-LCD,Spatial Light Modulator,Ultra high resolution,Holography,Phase modulation,Active-matrix displays,TFTs,Phase Change Materials
更新于2025-09-12 10:27:22
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Thermal and optical performance characteristics of a spatial light modulator with high average power picosecond laser exposure applied to materials processing applications
摘要： A spatial light modulator (SLM) addressed with Computer Generated Holograms (CGH’s) can create structured light fields when an incident laser beam is diffracted by a phase CGH. The power handling limitations of SLMs based on a liquid crystal layer have always been of some concern. Now, with careful engineering of chip thermal management, we present the detailed optical phase and temperature response of a liquid cooled SLM exposed to picosecond laser average powers up to 220W at 1064nm – new knowledge critical for determining device performance at high laser powers. SLM chip temperature rose linearly with incident laser exposure, increasing by only 5°C at 220W incident power, measured with a thermal imaging camera. Thermal response time with continuous exposure was 1-2 seconds. The optical phase response with incident power approaches 2π radians with average powers up to 130W while above this power, liquid crystal thickness variations limit phase response to just over π radians. These remarkable performance characteristics show that liquid crystal based SLM technology is highly robust when efficiently cooled. High speed, multi-beam plasmonic surface micro-structuring at a coverage rate of 8cm2s-1 is achieved on polished metal surfaces at 25W exposure, while diffractive multi-beam surface ablation on stainless steel at an ablation rate of ～4mm3min-1 is demonstrated with average power 100W. Continuous exposure for many hours exceeding 100W laser power did not result in any detectable drop in diffraction efficiency hence no permanent changes in SLM phase response characteristics have been observed This research work will help to accelerate the use of liquid crystal SLMs for both scientific and ultra-high throughput laser-materials micro-structuring applications.
关键词： Spatial light modulator,active cooling,high average power picosecond laser,high power laser micro-machining
更新于2025-09-12 10:27:22