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《中国科学:物理学 力学 天文学(英文版)》2021,(9)
Nonlinear plasmonic metasurfaces are compatible with complementary metal oxide semiconductor technology and highly promising for on-chip optical switching and modulations and nanoscale frequency conversions. However, the low nonlinearoptical response of metasurface devices limits their practical applications. To circumvent this constraint, we propose the design of a nanocavity plasmonic metasurface, in which the strong light localization in the nanocavity can be used to boost the efficiency of second-harmonic generation. Compared with the single-layer counterpart, experimental results show that the intensity of the second-harmonic waves in the nanocavity metasurface is enhanced by ~790 times. The proposed nanocavity plasmonic metasurfaces in this work may open new routes for developing highly efficient nonlinear metacrystals for on-chip nonlinear sources,nonlinear image encryption, information processing, and so on. 相似文献
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Pu Sun Yuwei Sun Haolin Yang Xinan Xu Yi Jin Sailing He 《Laser \u0026amp; Photonics Reviews》2024,18(4):2300263
Dielectric metasurfaces are highly sought-after since they have found a variety of linear and nonlinear applications. Here, a novel transmission modulation is presented for pulsed laser generation by directly exploiting the enhanced Kerr effect from a periodic array of silicon nanodisks. The Mie resonance of the unit cells enhances the Kerr effect of the silicon material and is redshifted by the latter, so that the transmission of the metasurface at the working wavelength is strongly modulated (the observed modulation depth is above 3% under moderate exciting power). By inserting the fabricated metasurface as a self-modulator into a ring cavity fiber laser, stable Q-switched pulse laser output is achieved with a duration of 1.4 µs and a repetition rate of 60 kHz. This work opens a door for ultra-thin low-loss dielectric metasurfaces to efficiently shape the operation of pulsed lasing based on their enhanced nonlinear effects and flexible propagation manipulation. 相似文献
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Internal Structure Tailoring in 3D Nanoplasmonic Metasurface for Surface-Enhanced Raman Spectroscopy
Tao Jiang Pratibha Goel Hui Zhao Rui Ma Linghua Zhu Xiangjiang Liu Longhua Tang 《Particle & Particle Systems Characterization》2020,37(1):1900345
Tunable nanoplasmonic metasurfaces have resulted in many versatile platforms for sensing applications including surface-enhanced Raman scattering (SERS)-based detection. However, to date, their fabrication still faces challenges in uniformity, repeatability, and controllability. Here, a novel large-area and hierarchical nanoplasmonic array with controlled internal structure and tunable plasmonic properties is reported, relying on controllably tailoring the single nanosphere on a uniform double-layered array into a well-defined nanoflower structure. The fabrication involves colloidal self-assembly, lithography, and plasmonic metal coating. First, a uniformly distributed double-layered colloidal array is fabricated via an ethanol-assisted self-assembly technique. Next, with the help of inductively coupled plasma dry etching, the lower layer is transformed to the nanoflower array with well-defined petal shape. Subsequently, a gold film with controlled thickness is deposited onto the nanoflower structured array, resulting in a tunable optical and SERS-active enhancement effect. Furthermore, 3D finite-difference time-domain simulation shows multiple enhancement sites inside the nanoflower array. Such a brand-new 3D structured array has the potential for varied applications, ranging from SERS sensors to light regulation. 相似文献
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电磁超表面属于超材料的一种,是由许多亚波长纳米结构单元组成的二维功能性平面结构.根据惠更斯原理,超表面阵列可以任意调控光波的相位、振幅和偏振.与传统器件相比,基于这种超材料设计的光学功能器件最大的优势是其具有极薄的厚度.本文首先介绍了广义斯涅耳定律以及纳米单元结构调控相位的基本原理,重点归纳了电磁超表面在透镜成像技术方面的研究进展,包括等离子体超表面、全介质超表面以及金属/介质混合式超表面在成像方面的应用,最后指出了超表面在成像方面尚未解决的前沿问题以及与实际应用接轨的重要问题,希望能为以后的深入研究提供一定的参考和借鉴. 相似文献
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Conventional metasurfaces based on geometric phase are constrained to spin-locked phase profile, resulting in mirrored functionalities for different spins. A single flat device that enables independent manipulation of wavefronts in two orthogonal circularly polarized channels is of paramount importance in wireless and optical communications. In this work, by tuning the dimension and rotation angle of H-shaped meta-atoms to synthesize propagating phase and geometric phase, spin-dependent plasmonic metasurfaces are presented to manipulate circularly polarized waves in the visible band. To verify the capability of spin-dependent wavefront manipulation, three metasurfaces are implemented. The first metasurface generates vortex beams with orbital angular momentum (OAM) l = 1 under left-handed circularly polarized (LCP) incidence and l = 2 under right-handed circularly polarized (RCP) incidence. By introducing convolution operation, the second metasurface is capable of producing vortex beams with different OAMs and different directions for two spins. The third metasurface produces dual-beam and quad-beam with different OAMs for different circular polarizations. This scheme can provide a new pathway in ultracompact nanophotonic devices and systems. 相似文献
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Surface waves(SWs) are a special form of electromagnetic waves that travel along the boundary between a metal and a dielectric. The special optical properties of SWs render them very attractive in applications, such as subdiffractional lithography, novel biochemical sensors, and ultrafast integrated circuitries. Herein, we present a review of our recent progress in excitation and manipulation of terahertz SWs due to interference or coupling between a pair of slit resonators in metasurfaces, showing the ability to devise ultrathin and compact plasmonic components. 相似文献
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Chirality, which describes the broken mirror symmetry in geometric structures, exists macroscopically in our daily life as well as microscopically down to molecular levels. Correspondingly, chiral molecules interact differently with circularly polarized light exhibiting opposite handedness(left-handed and right-handed). However, the interaction between chiral molecules and chiral light is very weak. In contrast, artificial chiral plasmonic structures can generate "super-chiral" plasmonic near-field, leading to enhanced chiral light-matter(or chiroptical) interactions. The "super-chiral" near-field presents different amplitude and phase under opposite handedness incidence, which can be utilized to engineer linear and nonlinear chiroptical interactions. Specifically,in the interaction between quantum emitters and chiral plasmonic structures, the chiral hot spots can favour the emission with a specific handedness. This article reviews the state-of-the-art research on the design, fabrication and chiroptical response of different chiral plasmonic nanostructures or metasurfaces. This review also discusses enhanced chiral light-matter interactions that are essential for applications like chirality sensing, chiral selective light emitting and harvesting. In the final part, the review ends with a perspective on future directions of chiral plasmonics. 相似文献
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In view of wide applications of structured light fields and plasmonic vortices, we propose the concept of compound plasmonic vortex and design several structured plasmonic vortex generators. This kind of structured plasmonic vortex generators consists of multiple spiral nanoslits and they can generate two or more concentric plasmonic vortices. Different from Laguerre–Gaussian beam, the topological charge of the plasmonic vortex in different region is different. Theoretical analysis lays the basis for the design of radially structured plasmonic vortex generators and numerical simulations for several examples confirm the effectiveness of the design principle. The discussions about the interference of vortex fields definite the generation condition for the structured vortex. This work provides a design methodology for generating new vortices using spiral nanoslits and the advanced radially structured plasmonic vortices is helpful for broadening the applications of vortex fields. 相似文献
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We propose the inclusion of a structured pattern of nanoscale metal wires in a silica fiber to form a symmetric plasmonic waveguide. The surface plasmon polariton modes within the waveguide are studied by varying the wire diameter and spacing. Simulation results show that hybridization of the single-wire mode and the gap plasmon mode can yield a hybrid mode with optimum propagation lengths comparable to those reported for other structures but with better light confinement. The fiber can be easily doped with a gain material to offset the loss so that the resultant waveguide will be useful for integration with electronic circuits at nanometer dimensions. 相似文献
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Optical Review - Plasmonic nanostructures or metasurfaces have recently been actively researched for structural color generation. Controlling the plasmonic resonant wavelengths of surface plasmon... 相似文献
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Heyi Zhang Runxuan Zhang Canhui He Changqing Li Zhengyong Song 《Annalen der Physik》2023,535(9):2300197
As a burgeoning approach to modulate electromagnetic waves, metasurfaces fascinate many researchers. However, it is a persistent problem to realize independent wavefront tailoring in different polarization states. In this work, anisotropic plasmonic metasurfaces are presented with linear polarization-dependent focusings. The designed plasmonic meta-atoms consist of cross-shaped gold, silica spacer, and gold substrate. Phase modulation in different polarization channels is independently achieved by adjusting the dimensions of cross-shaped gold in x- and y-directions. Three metasurfaces are presented to verify linear polarization-dependent focusings at 200 THz. First, a focusing metasurface is designed with focal lengths of 5.2 µm under x-polarized incidence and 6.5 µm under y-polarized incidence. Second, by applying convolution operation, the second metasurface exhibits different focusings with different deflection angles at opposite directions under orthogonally polarized incidences. Finally, a multi-focal metasurface is demonstrated, which switches between dual- and quad-focal points depending on polarization state. The work may provide a novel platform for near-infrared integrated photonics. 相似文献
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本文用时域有限差分法对硅层等效厚度为100 nm的具有不同前后光栅周期的介质/金属双光栅结构薄膜太阳能电池进行了模拟分析,比较了三角形最佳相同与不同周期光栅结构的吸收光谱特性,分析了光栅高度、填充比、硅吸收层厚度对最佳相同和不同周期光栅结构光吸收特性的影响,以及相应结构中导致光吸收增强的共振模式.结果表明前后光栅周期为1:1的共形双光栅结构中存在光泄漏现象,偏离1:1后的光栅结构可有效地抑制低级次衍射光的泄漏,前光栅周期小于后光栅周期的结构光吸收性能的提高来自于平面波导模式在吸收层中的有效激发和传播,而前光栅周期大于后光栅周期的结构光吸收性能的提高则来自于后光栅界面上所激发的等离子体极化模式.在较厚的硅吸收层厚度,前后光栅周期比为1:2和1:3的电池结构也会出现光泄漏现象,从而使具有最大光吸收效率的结构偏离这些周期比结构的位置. 相似文献
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《中国物理 B》2015,(8)
It is interesting that in preparing process of nanosilicon by pulsed laser, the periodic diffraction pattern from plasmonic lattice structure in the Purcell cavity due to interaction between plasmons and photons is observed. This kind of plasmonic lattice structure confined in the cavity may be similar to the Wigner crystal structure. Emission manipulation on Si nanostructures fabricated by the plasmonic wave induced from pulsed laser is studied by using photoluminescence spectroscopy.The electronic localized states and surface bonding are characterized by several emission bands peaked near 600nm and 700nm on samples prepared in oxygen or nitrogen environment. The electroluminescence wavelength is measured in the telecom window on silicon film coated by ytterbium. The enhanced emission originates from surface localized states in band gap due to broken symmetry from some bonds on surface bulges produced by plasmonic wave in the cavity. 相似文献
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Guangzhou Geng 《中国物理 B》2022,31(12):124207-124207
The photonic spin Hall effect has attracted considerable research interest due to its potential applications in spin-controlled nanophotonic devices. However, realization of the asymmetrical photonic spin Hall effect with a single optical element is still a challenge due to the conjugation of the Pancharatnam-Berry phase, which reduces the flexibility in various applications. Here, we demonstrate an asymmetrical spin-dependent beam splitter based on a single-layer dielectric metasurface exhibiting strong and controllable optical response. The metasurface consists of an array of dielectric nanofins, where both varying rotation angles and feature sizes of the unit cells are utilized to create high-efficiency dielectric metasurfaces, which enables to break the conjugated characteristic of phase gradient. Thanks to the superiority of the phase modulation ability, when the fabricated metasurface is under normal incidence with a wavelength of 1550 nm, the left-handed circular polarization (LCP) light exhibits an anomalous refraction angle of 28.9°, while the right-handed circular polarization (RCP) light transmits directly. The method we proposed can be used for the flexible manipulation of spin photons and has potentials in high efficiency metasurfaces with versatile functionalities, especially with metasurfaces in a compact space. 相似文献
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以广义斯奈尔定律为理论依据,对五模声学超表面定向反射的基本原理进行了解析推导和理论分析,获得了五模超表面的理想连续物性参数分布,并给出了五模超表面尺寸设计准则;然后将超表面离散,获得离散单胞的密度和体积模量,并以此为目标进行五模微结构设计,采用均匀化理论计算微结构的等效物性参数;最后,进行了水下声场的声波定向反射调控仿真实验,研究了入射波频率对超表面定向反射性能的影响,仿真结果展现了五模超表面宽频有效的声波调控能力以及调控的可靠性和准确性。本文的研究工作为五模声学超表面的设计和物理实现提供理论指导。 相似文献
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《中国光学快报(英文版)》2021,(7)
In this paper,we experimentally demonstrate ultrafast optical control of slow light in the terahertz(THz) range by combining the electromagnetically induced transparency(EIT) metasurfaces with the cut wire made of P~+-implanted silicon with short carrier lifetime.Employing the optical-pump THz-probe spectroscopy,we observed that the device transited from a state with a slow light effect to a state without a slow light effect in an ultrafast time of 5 ps and recovered within 200 ps.A coupled oscillator model is utilized to explain the origin of controllability.The experimental results agree very well with the simulated and theoretical results.These EIT metasurfaces have the potential to be used as an ultrafast THz optical delay device. 相似文献