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The optical vortex beam has widely been studied and used because of its unique orbital angular momentum(OAM). To generate and control OAM in compact and integrated systems, many metallic metasurface devices have been proposed,however, most of them suffer from the low efficiency. Here, we propose and experimentally verify a high-efficiency monolayer metallic metasurface composed of semicircular nano-grooves distributed with detour phase. The metasurface can generate single or an array of OAM with... 相似文献
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Controlling both amplitude and phase of light in the subwavelength scale is a challenge for traditional optical devices. Here, we propose and numerically investigate a novel plasmonic meta-hologram, demonstrating broadband manipulation of both phase and amplitude in the subwavelength scale. In the meta-hologram, phase modulation is achieved by the detour phase distribution of unit cells, and amplitude is continuously modulated by a T-shaped nano-cavity with tunable plasmonic resonance. Compared to phase-only holograms, such a metahologram could reconstruct three-dimensional(3D) images with higher signal-to-noise ratio and better image quality, thus offering great potential in applications such as 3D displays, optical communications, and beam shaping. 相似文献
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An efficient and inexpensive method that uses a glass plate mounted onto a motorized rotating stage as a beam-steering device for the generation of dynamic optical traps is reported.Force analysis reveals that there are drag and trapping forces imposed on the bead in the opposite directions,respectively,in a viscous medium.The trapped bead will be rotated following the beam’s motion before it reaches the critical escape velocity when the drag force is equal to the optical trapping force.The equilibrium condition facilitates the experimental measurement of the drag force with potential extensions to the determination of the viscosity of the medium or the refractive index of the bead.The proposed technique can easily be integrated into conventional optical microscopic systems with minimum modifications. 相似文献
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针对纳米尺度热现象研究的需求,基于表面等离激元光镊对金纳米颗粒的动态操控能力,设计了一种实时、动态、可控的纳米热源。利用有限元法对光镊系统中金纳米颗粒的光热效应与表面等离激元电磁场强度的关系进行了模拟,阐明了由于表面等离激元和局域表面等离激元的耦合作用导致的电磁场能量聚集和增强,以及同时实现的金属纳米颗粒的光热效应;分析了在该光镊系统捕获金属颗粒过程中颗粒所产生的热效应,并由此得到了实时控制纳米热源热功率的方法。在理论研究的基础上设计实验并证实了该光镊系统中金纳米颗粒基于光热效应的加热能力。结合表面等离激元光镊系统对纳米热源的精确定位操控能力,该系统为纳米尺度热现象的研究提供了灵活而可靠的手段。 相似文献
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