- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Phase Conjugation and Mode Conversion in Stimulated Parametric Down-Conversion with Orbital Angular Momentum: a Geometrical Interpretation
摘要： We report on an experiment that investigates the spatial mode conversion in the process of parametric down-conversion seeded by a light beam in a superposition of orbital angular momentum modes. This process is interpreted in terms of a geometric representation of first-order spatial modes in a Poincaré sphere, providing an intuitive image of the phase conjugation and the topological charge conservation. We also make a comparison with the analogous phenomenon for optical parametric oscillators.
关键词： Orbital angular momentum,Parametric down-conversion,Optics,Phase conjugation
更新于2025-09-23 15:23:52
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Implementation of quantum permutation algorithm with classical light
摘要： We report the experimental implementation of quantum permutation algorithm using polarization and orbital angular momentum of the classical optical beam. The easy-handling optical setup to realize all eight cyclic permutation transformations for an four-dimensional system has been constructed. The two-to-one speed-up ratio to determine the parity of each permutation has been demonstrated. Moreover, we have theoretically discussed the extension to the case with eight elements, and the limitations on the generalization of our proposal to higher-dimensional cases. Our scheme exhibits outstanding stability and demonstrates that optical quantum computation is possible using classical states of light.
关键词： classical light,quantum permutation algorithm,polarization,orbital angular momentum
更新于2025-09-23 15:23:52
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Broadband generation of the first-order OAM modes in two-mode fiber by offset splicing and fiber rotating technology
摘要： We demonstrate a simple, compact, and cost-effective all-fiber structure to generate the first-order orbital angular momentum (OAM) modes over a broad wavelength range. The offset splicing between a polarization-maintaining single mode fiber (PM-SMF) and a two-mode fiber (TMF) is adopted to excite LP11 mode in the TMF from LP01 mode in SMF. Then the OAM ± 1,1 modes are generated by rotating a customized fiber rotator, which can modulate the phase difference of the two degenerate LP11 modes (OAM ± 1,1 = LP11a ± i × LP11b). The interference phenomenon formed between OAM and Gaussian beams, which displays a fork-shape or spiral interference pattern, is used to confirm the generation of OAM modes. It should be noted that a PM fiber coupler and PM-SMFs are utilized in the experiment, which can avoid coupling of modes with orthogonal polarizations and then improves the OAM mode stability. Besides, the complexity of the OAM generation system is also reduced because the devices like polarization controller and half-wave plate are omitted by employing PM fibers. Based on this simple offset splicing and fiber rotating technology, the broadband generation of OAM ± 1,1 modes are experimentally demonstrated in wavelength range of 1530–1566 nm.
关键词： Fiber rotating,Polarization-maintaining single mode fiber,Two mode fiber,Offset-splicing,Orbital angular momentum mode
更新于2025-09-23 15:23:52
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Control of orbital angular momentum of light in optofluidic infiltrated circular photonic crystal fibers
摘要： Orbital angular momentum (OAM) of light has been of great interest to enhance the data transmission capacity in optical communication systems. In this regards, new designs of optical fibers have been developed to transmit OAM modes. Circular photonic crystal fibers (C-PCFs) with an air-core in the center are good candidates for guiding OAM of light. By changing the geometrical parameters of the C-PCFs, one can control the topological charge (l) associated with OAM order. However, practically it is of significant interest to keep the geometrical parameters fixed and control the OAM characteristics by introducing optical fluid into the C-PCF. Therefore, in this paper, we propose for the first time controlling OAM characteristics such as l, dispersion and confinement loss based on optofluidic infiltrated C-PCFs. To this end, optofluidics with various refractive indices are introduced into the first ring of air holes in the cladding and mode characteristics are compared with those of uninfiltrated C-PCF. The results show that the OAM modes can be well controlled in optofluidic-infiltrated C-PCFs over the wavelength range of 1.25-2.0 μm with good dispersion and loss characteristics. Also, the dispersion curve can be flattened when an optical fluid with a proper refractive index is infiltrated into the C-PCF.
关键词： circular photonic crystal fibers,orbital angular momentum,optical fluid,mode control.
更新于2025-09-23 15:22:29
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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) - Three Methods to Generate Orbital Angular Momentum Beams in Microwaves
摘要： This paper reviews three methods to generate orbital angular momentum (OAM) beams in microwave region. Circular patch array, Vivaldi connecting array and microstrip ring antenna are the potential candidates. The first two utilizes phased array technique, which needs complex feeding network, while the later method uses the higher modes of microstrip ring. Vortex OAM beams can be observed in all the methods.
关键词： Orbital angular momentum,microstrip ring antenna,patch antenna array,Vivaldi connecting array
更新于2025-09-23 15:22:29
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Bandwidth-limited orbital angular momentum mode of Bessel Gaussian beams in the moderate to strong non-Kolmogorov turbulence
摘要： We investigate the effects of the moderate to strong fluctuation on the propagation of orbital angular momentum (OAM) modes carried by Bessel Gaussian beams in turbulent atmosphere. The analytic expression of the received probability of the signal and crosstalk OAM mode is derived based on the theories of extended Rytov and non-Kolmogorov turbulence. Our results show that turbulence with smaller non-Kolmogorov index, smaller inner-scale factor is more easily to induce OAM crosstalk between modes. With the increase of turbulence strength, the OAM spreads from adjacent modes to peripheral modes. Our results also indicate that the received signal intensity can be improved by use of Bessel Gaussian beams with small initial radii of beam, low OAM quantum number and long wavelength.
关键词： Bandwidth-limited mode,Non-Kolmogorov turbulence,Extended Rytov theory,Bessel Gaussian beam,Orbital angular momentum
更新于2025-09-23 15:22:29
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Laguerre–Gauss and Hermite–Gauss soft X-ray states generated using diffractive optics
摘要： Light’s capacity to carry angular momentum is integral to our knowledge of physics and ability to probe matter. In addition to spin, photons can occupy free-space orbital angular momentum eigenstates. Visible light orbital angular momentum is used in quantum information experiments, super-resolution microscopy, optical tweezers and angular momentum transfer to atoms in optical lattices. Soft X-ray orbital angular momentum applications, slowed by the lack of suitable optics and the rarity of coherent X-ray sources, could enable the direct alteration of atomic states through orbital angular momentum exchange, and methods to study the electronic properties of quantum materials. We have made soft X-ray diffractive optics that generate single Laguerre–Gauss modes, observed carrying up to 30? angular momentum per photon, or their superpositions. We also present Hermite–Gauss diffractive optics and a soft X-ray orbital angular momentum analyser. These tools could enable both the manipulation and finer characterization of topologically complex electronic matter, such as magnetic skyrmions.
关键词： Hermite–Gauss modes,Diffractive optics,Laguerre–Gauss modes,Soft X-ray,Orbital angular momentum
更新于2025-09-23 15:22:29
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A shared aperture 1-bit metasurface for orbital angular momentum multiplexing
摘要： In this letter, a shared aperture 1-bit metasurface for orbital angular momentum (OAM) multiplexing is studied. A phased array antenna fed by the phase shift network is embedded on the reflective aperture of the 1-bit metasurface. The proposed device can work on reflectarray mode from 7.1GHz to 7.5GHz and phased array mode from 7GHz to 7.5GHz. Correspondingly, OAM vortex beam with topological charge l = -1 and l = 1 can be generated. The transmission coefficient between the two working modes is below -30dB and the envelop correlation coefficient (ECC) is quite close to 0, which reveals the excellent isolation and diversity performance. A prototype of the proposed device is fabricated and tested. The measured S parameters and radiation patterns agree well with the simulation results.
关键词： phased array,reflectarray,metasurface,Orbital angular momentum (OAM) multiplexing
更新于2025-09-23 15:22:29
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Optical orbital angular momentum under strong scintillation
摘要： The evolution of classical optical fields propagating through atmospheric turbulence is investigated under arbitrary conditions. We use the single-phase screen (SPS) method and the infinitesimal propagation equation (IPE), a multiphase screen (MPS) method, to compute the optical power fractions retained in an input Laguerre-Gauss (LG) mode or transferred to higher-order LG modes. Although they show the same trend while the scintillation is weak, the IPE and SPS predictions deviate when the strength of scintillation passes a certain threshold. These predictions are compared with numerical simulations of optical fields propagating through turbulence. The simulations are performed using an MPS model, based on the Kolmogorov theory of turbulence, for different turbulence conditions to allow comparison in both weak and strong scintillation. The numerical results agree well with the IPE results in all conditions, but they deviate from the SPS results for strong scintillation.
关键词： multiphase screen method,scintillation,infinitesimal propagation equation,atmospheric turbulence,Laguerre-Gauss modes,single-phase screen method,optical orbital angular momentum
更新于2025-09-23 15:22:29
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An Orbital Angular Momentum-Based Array for In-Band Full-Duplex Communications
摘要： A uniform circular array (UCA) with dual orbital angular momentum (OAM) modes is proposed for in-band full-duplex applications. The proposed scheme includes two concentric ring subarrays for transmitting and receiving, respectively, where all elements are operated under the same linear polarization. To suppress the self-interference resulting from the mutual coupling, an OAM mode-selection method related to the proposed configuration is discussed. Results indicate that good isolation performance between the transmitter and receiver can be achieved by using the proposed scheme. To validate the performance, a demonstrator with OAM modes of -1 and -2 at Ku-band is developed, fabricated, and measured. Measurements show a relative bandwidth of 21.3% from 13.5 to 16.7 GHz, referring to a 40-dB suppression level, is achieved and the desired radiations are found.
关键词： self-interference suppression,uniform circular array,full-duplex,mutual coupling,Orbital angular momentum
更新于2025-09-23 15:22:29