- 标题
- 摘要
- 关键词
- 实验方案
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Vortex Beam Encoded All-Optical Logic Gates Based on Nano-Ring Plasmonic Antennas
摘要： Vortex beam encoded all-optical logic gates are suggested to be very important in future information processing. However, within current logic devices, only a few are encoded by using vortex beams and, in these devices, some space optical elements with big footprints (mirror, dove prism and pentaprism) are indispensable components, which is not conducive to device integration. In this paper, an integrated vortex beam encoded all-optical logic gate based on a nano-ring plasmonic antenna is proposed. In our scheme, by defining the two circular polarization states of the input vortex beams as the input logic states and the normalized intensity of the plasmonic field at the center of the nano-ring as the output logic states, OR and AND (NOR and NAND) logic gates are realized when two 1st (1st) order vortex beams are chosen as the two input signals; and a NOT logic gate is obtained when one 1st order vortex beam is chosen as the input signal. In addition, by defining the two linear polarization states (x and y polarization) of the input vortex beams as the two input logic states, an XNOR logic gate is realized when two 1st order vortex beams are chosen as the two input signals.
关键词： vortex beam,all-optical logic gates,plasmonic
更新于2025-09-11 14:15:04
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LINEAR MOMENTUM DENSITY OF A GENERAL LORENTZ-GAUSS VORTEX BEAM IN FREE SPACE
摘要： Based on the Collins integral, an analytical expression of a general Lorentz-Gauss vortex beam propagating in free space is derived, which allows one to calculate the linear momentum density of a general Lorentz-Gauss vortex beam in free space. The linear momentum density distribution of a general Lorentz-Gauss vortex beam propagating in free space is graphically demonstrated. The x- and y-components of the linear momentum density are composed of two lobes with the equivalent area and the opposite sign. Therefore, the overall x- and y-components of the linear momentum in an arbitrary reference plane are equal to zero. The longitudinal component of the linear momentum density is proportional to the intensity distribution. The influences of the Gaussian waist, the width parameters of the Lorentzian part, the axial propagation distance, and the topological charge on the linear momentum density distribution of a general Lorentz-Gauss vortex beam in free space are examined in detail.
关键词： free space propagation,linear momentum density,Lorentz-Gauss vortex beam,Collins integral
更新于2025-09-11 14:15:04
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Study on the influence of phase noise on coherent beam combined Bessel-Gaussian beam
摘要： Coherent beam combining (CBC) technology is one of the effective methods to obtain the high power laser beam, but the quality of the combined beam is significantly affected by the random phase noise among the sub-beams. In this work, a method for generating a combined Bessel-Gaussian (CBG) beam based on CBC technology is proposed. The correlation coefficient is adopted to evaluate the influence of phase noise on CBG beam including the Gaussian phase noise (GPN) and measured fiber laser phase noise (FLPN). The research results of GPN show that the spiral phase of the n-order CBG beam is unaffected by noise when the amplitude of phase noise is less than λ/5. The phase noise of fiber laser is measured, and its amplitude is around λ/10. Therefore, the spiral phase of the CBG beam is unaffected by the measured FLPN. Moreover, the resisted ability of the CBG beam against phase noise is improved efficiently through increasing the number of sub-beams.
关键词： Phase noise,Vortex beam,Coherent beam combining technology,Correlation coefficient
更新于2025-09-10 09:29:36
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A Novel Broadband Bi-Functional Metasurface for Vortex Generation and Simultaneous RCS Reduction
摘要： In this paper, a broadband bi-functional metasurface is presented with capabilities of generating vortex beam for y-polarization and reducing the backward radar cross section (RCS) for x-polarization. With careful optimization, a meta-atom is first designed to control reflection phases for orthogonally polarized wave independently. Then, an integrated phase profile is employed to convert y-polarized spherical wavefront into a vortex spiral one, shaping a vortex high gain beam in the far-field region. By arranging a checkerboard-like phase profile onto the surface for x-polarization, the reflected wave in the backward direction will be canceled, consequently leading to the backward RCS reduction for x-polarization. Combining the above-mentioned cases into a whole, a compact bi-functional metasurface is designed, simulated, physically implemented, and finally measured. In good agreement with the simulated results, the measured ones show that the RCS reduction of 10 dB for x-polarization in comparison with a same-sized metallic plate can be realized over a 67.7 % frequency bandwidth (9–18.2 GHz). Besides, high-efficiency vortex beam conversion effect for y-polarization over a broad range of 11.2–18.2 GHz (47.6%) can also be observed from the measured results.
关键词： vortex beam generator,RCS reduction,Metasurface,bi-functional
更新于2025-09-09 09:28:46
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A multi-functional vortex beam generator based on transparent anisotropic metasurface
摘要： Vortex beam generators are increasingly in demand for their enormous potential in improving communication capability. Along with the continuous integration of electronic product, devices with single function can not satisfy the requirements of the people. Here, by employing an anisotropic metasurface (MS), we propose a transparent multi-functional vortex beam generator to obtain vortex beams with reconfigurable polarization status. An anisotropic element is firstly optimized to control x- and y-polarized wave independently, and then is applied to assemble a vortex beam generator that is not only able to convert spherical wavefront into a vortex one but also able to transform linearly polarized mode into the circular polarized counterpart. Interestingly, the polarized status of the generated vortex beam changes from x-polarization to left hand circularly polarization (LHCP) to y-polarization and finally to right hand circularly polarization (RHCP) when the spot source is rotated with different angles. For verification, the prototype of the practical configuration is fabricated and measured. Coinciding well with the simulated results, the measured ones show that linearly polarized spherical wave has been converted into LHCP or RHCP vortex beams with operating efficiency of 85.8% or 83.3% respectively.
关键词： vortex beam,multi-function,metasurface
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Generation of Broadband Multiple OAM Modes Using Pancharatnam-Berry Metasurface
摘要： Vortex beams carrying orbital angular momentum (OAM) have been extensively realized using different approaches. Here, we present a Pancharatnam-Berry (PB) metasurface to generate broadband multiple vortex beams, which can carry different OAM modes towards different directions. The proposed PB metasurface could control the circularly polarized incident waves by attaching geometric phase to the orientation angle of the anisotropic meta-atoms. This design is numerically demonstrated at Ku band (12-18 GHz) and can be further exploited for OAM multiplexing in the communication systems.
关键词： vortex beam,Pancharatnam-Berry (PB) phase,Metasurface,orbital angular momentum (OAM)
更新于2025-09-04 15:30:14
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Effects of anisotropic oceanic turbulence on the propagation of the OAM mode of a partially coherent modified Bessel correlated vortex beam
摘要： We have studied the impacts of anisotropic turbulence on the orbital angular momentum (OAM) mode of a partially coherent modified Bessel correlated vortex beam propagation in an oceanic channel. In the weak turbulence paraxial channel, a new model of the probability density of OAM modes has been established. Effects of specific parameters of the oceanic turbulence on it have been studied, it is shown that there is an optimizing receiving aperture diameter in the specific interval of the ratio of temperature and salinity (cid:2) , which can reduce the effect of (cid:2) on the normalized energy weight of OAM modes and the reception of fluctuation signal. The effect of oceanic turbulence with higher anisotropy on the OAM signal is weaker than the turbulence possessing lower anisotropy. We can choose the mode carrying lower OAM quantum number to transfer information more efficiently, and we can utilize the OAM mode with large energy level difference between modes and so on to reduce mode interference and enhance the information capacity of optical communication links.
关键词： optical communication,partially coherent modified Bessel correlated vortex beam,propagation,OAM mode,anisotropic oceanic turbulence
更新于2025-09-04 15:30:14
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[IEEE 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Xuzhou (2018.7.21-2018.7.24)] 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Study of Propagation of Airy Array Vortex Beams in Turbulent Atmosphere
摘要： A circular phased-locked Airy beam array carrying orbital angular momentum (OAM) propagating through turbulent atmosphere is investigated in detail. The results testify that the OAM modes generated by the array are closely associated with the number of beamlets, requiring the number of beamlets at least twice more than the values of the OAM signal precisely. Furthermore, through multiple-phase-screen simulations, it is shown that the anti-jamming performance of an Airy beam array is significantly enhanced.
关键词： Atmospheric optics,Atmospheric propagation,Airy array vortex beam
更新于2025-09-04 15:30:14