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Li L, Liu B, Guo Z. Robust orbital-angular-momentum-based underwater acoustic communication with dynamic modal decomposition method. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:3195-3205. [PMID: 38738938 DOI: 10.1121/10.0025988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/22/2024] [Indexed: 05/14/2024]
Abstract
Recently, acoustic communication employing orbital angular momentum (OAM) opens another avenue for efficient data transmission in aquatic environments. Current topological charge (TC) detection of OAM beams relies on the orthogonality among different-order OAM beams. However, such strategy requires measurements of the complete azimuthal acoustic pressure, which inevitably reduces the efficiency and increases the bit error rate (BER). To address these challenges, this study proposes a modified dynamic modal decomposition (DMD) method by partially sampling the acoustic field for precise TC detection. Numerical simulations confirm the accuracy of this approach in extracting single or multiple TCs magnitudes within a partially sampled acoustic field. We theoretically compare the performance of the modified DMD approach with conventional orthogonal decoding method. Simulation results indicate that our modified DMD scheme exhibits lower BER under the same noise interference and is more robust to the array misalignment. This research introduces an efficient demodulation solution for acoustic OAM communication, offering potential benefits for simplifying receiver array design and enhancing long-distance underwater data transmission.
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Affiliation(s)
- Liulin Li
- School of Computer Science and Information Engineering, Hefei University of Technology, Hefei 230009, China
| | - Bingyi Liu
- School of Computer Science and Information Engineering, Hefei University of Technology, Hefei 230009, China
| | - Zhongyi Guo
- School of Computer Science and Information Engineering, Hefei University of Technology, Hefei 230009, China
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Wang C, Gui L, Mei X, Chen H, Ding F, Meng C, Bozhevolnyi SI, Xu K. Intracavity spatially modulated metasurfaces for a wavelength-tunable figure-9 vortex fiber laser. OPTICS EXPRESS 2024; 32:6423-6431. [PMID: 38439345 DOI: 10.1364/oe.515612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 01/26/2024] [Indexed: 03/06/2024]
Abstract
Intracavity optical metasurfaces with compact and flexible light manipulation capabilities, effectively enrich the implementation of miniaturized and user-friendly orbital angular momentum (OAM) laser sources. Here we demonstrate a wavelength-tunable figure-9 Yb-doped vortex fiber laser solely with standard non-polarization-maintaining single-mode fibers, which utilizes a gap-surface plasmon (GSP) metasurface as the intracavity mode regulation component to generate OAM beams, extending the avenues and related applications for cost-effective OAM laser sources. Gained by the broadband operation range of the metasurface, the figure-9 fiber laser could emit OAM light with center wavelength tunable from 1020 nm to 1060 nm and of high mode purity (about 90%). OAM beams with different topological charges such as l = ±1 have been obtained by changing the metasurface design. The proposed fiber laser with the intracavity GSP metasurface provides a reliable and customized output of OAM beams at the laser source, holding great promise for a wide range of applications in optical communications, sensing, and super-resolution imaging.
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Kerridge-Johns WR, Srinivasa Rao A, Fujimoto Y, Omatsu T. Red, orange, and dual wavelength vortex emission from Pr:WPFGF fiber laser using a microscope slide output coupler. OPTICS EXPRESS 2023; 31:16607-16614. [PMID: 37157736 DOI: 10.1364/oe.491867] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Visible vortex beams have a large array of applications; however, the sources are often large or complex. Here, we present a compact vortex source with red, orange, and dual wavelength emission. This Pr:Waterproof Fluoro-Aluminate Glass fiber laser uses a standard microscope slide as an interferometric output coupler, yielding high quality first order vortex modes in a compact setup. We further demonstrate the broad (∼5 nm) emission bands in the orange (610 nm), red (637 nm) and near-infrared regions (698 nm), with the potential for green (530 nm) and cyan (485 nm) emission. This is a low-cost, compact and accessible device giving high quality modes for visible vortex applications.
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Zhang Q, Wang C, Dong X, Gao X. Control of transverse mode in a He-Ne laser using an astigmatic resonator. APPLIED OPTICS 2021; 60:10625-10631. [PMID: 35200925 DOI: 10.1364/ao.440596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/04/2021] [Indexed: 06/14/2023]
Abstract
The realization of output of the controllable transverse mode in a laser resonator has always been the key problem in applications of lasers. At present, the theory of optical resonators for passive resonators is relatively mature, but the non-uniformity of gain media greatly affects the output of the laser transverse mode for astigmatic resonators in operation; especially for gas lasers, controllable high-order modes have not been studied. To realize the theory of an astigmatic passive resonator of a gas laser as a good approximation of an active resonator, this paper develops the theory of selecting the laser eigenmode through an astigmatic resonator, and verifies that the two-dimensional tilt of the cavity mirror can break the axial symmetry. Controllable output of the laser mode is realized in real time and conveniently for the first time, to the best of our knowledge. This scheme is not only common to all kinds of lasers, but also has important research significance for the high-order modes required for real-time and rapid regulation of gas lasers under operating conditions.
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Lee DH, Kim HS, Han I, Bae JY, Yeo WJ, Jeong SK, Jeon M, Choi HJ, Kim DU, Lee KS, Chang KS, Lee W, Kim GH, Kim IJ. Generation of wavelength-tunable optical vortices using an off-axis spiral phase mirror. OPTICS LETTERS 2021; 46:4216-4219. [PMID: 34469977 DOI: 10.1364/ol.432413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
Wavelength-tunable optical vortices with a topological charge equal to l=1 of orbital angular momentum (OAM) were experimentally realized using a single off-axis spiral phase mirror (OSPM) with lasers of various visible-light wavelengths. Using an OSPM designed for 561 nm and an incidence angle of 45°, circular doughnut-shaped l=1 optical vortices were obtained at 561, 473, and 660 nm by rotating the OSPM to modify the laser incidence angle. Wavelength-tunable l=1 optical vortices were obtained at the respective incidence angles of 45°, 53.4°, and 33.7°, because the effective geometrical thickness of the OSPM, which determines the order of OAM, was identical at each wavelength. This flexible OSPM which operates over a wide wavelength range will provide continuously wavelength-tunable optical vortices for applications in the fields of advanced optics and photonics in which optical vortices with wide wavelength tunability are in demand.
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Wang D, Lei M, Lin S, Zheng Y, Kang S, Huang L. Generation of a mode-tunable optical vortex based on a mirror curvature dynamically controlled Z-shaped resonant cavity. OPTICS LETTERS 2021; 46:3079-3082. [PMID: 34197385 DOI: 10.1364/ol.422316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/28/2021] [Indexed: 06/13/2023]
Abstract
We report a novel, to the best of our knowledge, mode-tunable optical vortex generation method based on a mirror curvature dynamically controlled Z-shaped resonant cavity, a mode conversion beamline, and a reference laser beamline. By changing the mirror curvature of an intra-cavity deformable mirror (DM) at a certain pumping voltage and current, various Hermite-Gaussian (HG) mode beams were obtained in the Z-shaped resonant cavity of a laser diode pumped Yb:CALGO laser. The vortex beams were realized finally by using an external cavity astigmatism converter. In the experiment, the dynamic tuning of the 1st to 9th order HG mode beams and Laguerre-Gaussian mode vortex beams carrying different orbital angular momenta, ranging from 1ℏ to 9ℏ were achieved by dynamically adjusting the driving voltage of the DM.
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Acevedo CH, Batarseh M, Dogariu A. 3D intensity correlations in random fields created by vortex structured beams. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2021; 38:1024-1031. [PMID: 34263758 DOI: 10.1364/josaa.426531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/29/2021] [Indexed: 06/13/2023]
Abstract
We develop an analytical model for the 3D spatial coherence function of speckle fields generated by scattering of vortex and perfect optical vortex beams. The model is general and describes the spatial coherence along both the transversal and the longitudinal directions. We found that, on propagation, the 3D spatial coherence evolves differently for the different types of initially structured beams, which may affect their use in a variety of sensing applications.
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Detection and elimination of pulse train instabilities in broadband fibre lasers using dispersion scan. Sci Rep 2020; 10:7242. [PMID: 32350325 PMCID: PMC7190630 DOI: 10.1038/s41598-020-64109-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/31/2020] [Indexed: 11/25/2022] Open
Abstract
We use self-calibrating dispersion scan to experimentally detect and quantify the presence of pulse train instabilities in ultrashort laser pulse trains. We numerically test our approach against two different types of pulse instability, namely second-order phase fluctuations and random phase instability, where the introduction of an adequate metric enables univocally quantifying the amount of instability. The approach is experimentally demonstrated with a supercontinuum fibre laser, where we observe and identify pulse train instabilities due to nonlinear propagation effects under anomalous dispersion conditions in the photonic crystal fibre used for spectral broadening. By replacing the latter with an all-normal dispersion fibre, we effectively correct the pulse train instability and increase the bandwidth of the generated coherent spectrum. This is further confirmed by temporal compression and measurement of the output pulses down to 15 fs using dispersion scan.
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Shen Y, Wang X, Xie Z, Min C, Fu X, Liu Q, Gong M, Yuan X. Optical vortices 30 years on: OAM manipulation from topological charge to multiple singularities. LIGHT, SCIENCE & APPLICATIONS 2019; 8:90. [PMID: 31645934 PMCID: PMC6804826 DOI: 10.1038/s41377-019-0194-2] [Citation(s) in RCA: 384] [Impact Index Per Article: 76.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 08/04/2019] [Accepted: 08/20/2019] [Indexed: 05/05/2023]
Abstract
Thirty years ago, Coullet et al. proposed that a special optical field exists in laser cavities bearing some analogy with the superfluid vortex. Since then, optical vortices have been widely studied, inspired by the hydrodynamics sharing similar mathematics. Akin to a fluid vortex with a central flow singularity, an optical vortex beam has a phase singularity with a certain topological charge, giving rise to a hollow intensity distribution. Such a beam with helical phase fronts and orbital angular momentum reveals a subtle connection between macroscopic physical optics and microscopic quantum optics. These amazing properties provide a new understanding of a wide range of optical and physical phenomena, including twisting photons, spin-orbital interactions, Bose-Einstein condensates, etc., while the associated technologies for manipulating optical vortices have become increasingly tunable and flexible. Hitherto, owing to these salient properties and optical manipulation technologies, tunable vortex beams have engendered tremendous advanced applications such as optical tweezers, high-order quantum entanglement, and nonlinear optics. This article reviews the recent progress in tunable vortex technologies along with their advanced applications.
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Affiliation(s)
- Yijie Shen
- Key Laboratory of Photonic Control Technology (Tsinghua University), Ministry of Education, 100084 Beijing, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084 Beijing, China
| | - Xuejiao Wang
- National Engineering Laboratory for Public Safety Risk Perception and Control by Big Data (NEL-PSRPC), China Academy of Electronics and Information Technology of CETC, China Electronic Technology Group Corporation, 100041 Beijing, China
| | - Zhenwei Xie
- Nanophotonics Research Center, Shenzhen University, 518060 Shenzhen, China
| | - Changjun Min
- Nanophotonics Research Center, Shenzhen University, 518060 Shenzhen, China
| | - Xing Fu
- Key Laboratory of Photonic Control Technology (Tsinghua University), Ministry of Education, 100084 Beijing, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084 Beijing, China
| | - Qiang Liu
- Key Laboratory of Photonic Control Technology (Tsinghua University), Ministry of Education, 100084 Beijing, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084 Beijing, China
| | - Mali Gong
- Key Laboratory of Photonic Control Technology (Tsinghua University), Ministry of Education, 100084 Beijing, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084 Beijing, China
| | - Xiaocong Yuan
- Nanophotonics Research Center, Shenzhen University, 518060 Shenzhen, China
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