Article
Optics
Dong-Ho Lee, Hong Seung Kim, Ilkyu Han, Ji Yong Bae, Woo-Jong Yeo, Seok Kyung Jeong, Minwoo Jeon, Hwan-Jin Choi, Dong Uk Kim, Kye-Sung Lee, Ki Soo Chang, Wonkyun Lee, Geon Hee Kim, I. Jong Kim
Summary: Wavelength-tunable optical vortices with a topological charge equal to l=1 of orbital angular momentum were experimentally realized using a single off-axis spiral phase mirror, providing continuously wavelength-tunable optical vortices for applications in the fields of advanced optics and photonics. The flexible OSPM operates over a wide wavelength range, producing circular doughnut-shaped l=1 optical vortices by rotating the OSPM to modify the laser incidence angle at different visible-light wavelengths.
Article
Optics
Yiping Geng, Hao Hu, Xinru Ma, Xiaoxue Hu, Xinyue Chai, Xiaolei Wang, Sixing Xi, Zhuqing Zhu
Summary: In this study, various hollow structured optical fields were generated by adjusting the number and positions of multiple off-axis vortices loaded in a Gaussian beam. The focal-field characteristics of these fields after passing through a lens were theoretically analyzed and confirmed experimentally. This research is expected to contribute to the potential applications of off-axis vortex beams in optical field shaping, optical manipulation, and laser processing.
Article
Optics
Alexey A. Kovalev, Victor V. Kotlyar, Darya S. Kalinkina
Summary: The study focused on paraxial light beams formed by a continuous superposition of off-axis Gaussian beams. An analytical expression for a propagation-invariant off-axis elliptic Gaussian beam was derived, along with an analysis of its orbital angular momentum. The angular momentum of the elliptic beam consists of two terms, one intrinsic and the other dependent on the distance between the beam center and the optical axis. The study showed that the orientation of the ellipse in the transverse plane does not affect the normalized orbital angular momentum.
Article
Physics, Applied
Minghao Sun, Songhua Liu, Lixin Guo, Kai Huang, Mingjian Cheng
Summary: The scattering characteristics of electrically large arbitrarily shaped targets illuminated by an off-axis Laguerre-Gaussian (LG) vortex beam are compared to the on-axis incidence case. The results show that the scattering field distorts and orbital angular momentum (OAM) spectrum mixing occurs as the beam center offset and topological charge increase. The study also reveals OAM spectrum aliasing even for asymmetric targets, providing valuable insights for applying vortex beams in target detection and recognition.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Galina Kostyuk, Victoria Shkuratova, Andrey Petrov, Dmitriy Stepanyuk, Roman Zakoldaev
Summary: In this paper, a method for fabricating spiral phase plates using laser-induced microplasma on fused silica is proposed. The fabricated plate generates vortex beams with a topological charge of 1, and the conversion efficiency is approximately 75%.
OPTICAL AND QUANTUM ELECTRONICS
(2023)
Article
Optics
Amal Mirando, Yimin Zang, Qiwen Zhan, Andy Chong
Summary: A recent study has shown that a spatiotemporal optical vortex (STOV) can be generated from a light source with partial temporal coherence instead of using mode-locked lasers, providing a convenient and cost-effective transverse OAM source.
Article
Optics
Shuqing Chen, Zhiqiang Xie, Huapeng Ye, Xinrou Wang, Zhenghao Guo, Yanliang He, Ying Li, Xiaocong Yuan, Dianyuan Fan
Summary: The study introduces a simple approach based on a metal-dielectric-metal metasurface for off-axis polarization control in CVB multiplexing/demultiplexing, enabling high-capacity optical communication. The proposed multiplexers/demultiplexers are broadband and compatible with wavelength-division-multiplexing, achieving a transmission rate of 1.56 Tbit/s in a four-channel CVB communication system. This paves the way for more efficient and high-capacity CVB communication.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Article
Optics
Ke Hai Luo, Rui Ma, Han Wu, Xin Ying Li, Chun Xiang Zhang, Dian Yuan Fan, Jun Liu
Summary: In this study, broadband wavelength-tunable Laguerre-Gaussian (LG) modes with a controllable topological charge were generated using a random fiber laser and a digital micromirror device. This enables large-capacity data transmission in optical communication.
Article
Physics, Multidisciplinary
David R. Blackman, Yin Shi, Sallee R. Klein, Mihail Cernaianu, Domenico Doria, Petru Ghenuche, Alexey Arefiev
Summary: This study investigates an alternative electron injection method using a low-density foam target and a helical laser pulse. Three-dimensional simulations demonstrate that this method can generate a high-energy, short acceleration distance, and low-divergence electron beam.
COMMUNICATIONS PHYSICS
(2022)
Article
Optics
Mingxian Guo, Wei Le, Chao Wang, Guanghao Rui, Zhuqing Zhu, Jun He, Bing Gu
Summary: Compared with the on-axis vortex beam and the off-axis single vortex beam, the off-axis double vortex beam has more control degrees of freedom and brings rich physical properties. In this work, the generation, topological charge (TC), and orbital angular momentum (OAM) of off-axis double vortex beams are investigated theoretically and experimentally. The tilted lens method is demonstrated to detect the magnitudes, signs, and spatial distribution of two TCs of the off-axis double vortex beam. Moreover, the average OAM of the off-axis double vortex beam can be easily controlled by changing the relative position of two-phase singularities, enabling applications in multi-degrees of freedom particle manipulation, optical communication, and material processing.
Article
Optics
Shunlin Huang, Peng Wang, Xiong Shen, Jun Liu
Summary: A theoretical study on spatiotemporal optical vortex (STOV) light generation and propagation, analyzing the characteristics of output pulses with different topological charges, the evolution of intensity profiles, and the conservation of OAM in the space-time domain, providing guidance on the application of STOV.
Article
Optics
Ghanasyam Remesh, B. S. Athira, Shyamal Gucchait, Ayan Banerjee, Nirmalya Ghosh, Subhasish Dutta Gupta
Summary: This study investigates manifestations of orbital angular momentum induced effects in the diffraction of a radially polarized vector beam by an off-axis tilted aperture, demonstrating a proportional relationship between circular polarization degree and on-axis component of spin angular momentum density. The clear separation of right and left circular polarizations associated with positive and negative topological charges contributes to understanding alignment issues in systems involving vortex beams.
Article
Engineering, Electrical & Electronic
Zhiqiang Xie, Yanliang He, Xinrou Wang, Haisheng Wu, Canming Li, Huapeng Ye, Junmin Liu, Ying Li, Yatao Yang, Dianyuan Fan, Shuqing Chen
Summary: This study proposes a phase off-axis modulation strategy for (de)multiplexing the orbital angular momentum (OAM) modes. By encoding the binary Dammann optical vortex grating (DOVG) phase into a geometric phase metasurface consisting of metallic nanoantennas with spatially varying orientations on a dielectric-metal substrate. The experimental results demonstrate the successful (de)multiplexing of four OAM modes (-2, -1, 1, 2) through the multilevel diffraction of DOVG and its reverse process. The metasurface has a working wavelength range of 1260 nm to 1675 nm due to the dispersion-free geometric phase, and the mode symmetry of DOVG and the conjugate modulation of the geometric phase result in polarization insensitivity.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Ke Hu, Longqing Yi
Summary: It has recently been reported that ultraviolet harmonic vortices can be generated by a high-power circular-polarized laser pulse passing through a micro-scale waveguide. However, the harmonic generation typically quenches after a short distance due to the buildup of electrostatic potential. To overcome this obstacle, a hollow-cone channel is proposed, allowing the surface wave to maintain a high amplitude for a longer distance. Simulations show that the proposed scheme can achieve a very high efficiency (>20%) in producing harmonic vortices, which opens up possibilities for powerful optical vortices sources in the extreme ultraviolet regime.
Article
Physics, Applied
A. H. Tavabi, P. Rosi, A. Roncaglia, E. Rotunno, M. Beleggia, P. -H. Lu, L. Belsito, G. Pozzi, S. Frabboni, P. Tiemeijer, R. E. Dunin-Borkowski, V. Grillo
Summary: This study reports the use of an electrostatic micro-electromechanical systems-based device to generate high-quality electron vortex beams with more than 1000 quanta of orbital angular momentum. Diffraction and off-axis electron holography experiments demonstrate that the diameter of the vortex in the diffraction plane increases linearly with OAM, providing a means to calibrate the angular momentum content of the vortex. The current limitation in achieving electron vortex beams with even larger values of OAM is the breakdown voltage of the device. Potential solutions to overcome this problem are discussed.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Analytical
Alexey P. Porfirev, Svetlana N. Khonina, Nikolay A. Ivliev, Sergey A. Fomchenkov, Denis P. Porfirev, Sergey V. Karpeev
Summary: This study demonstrates the unique possibilities of processing azopolymers using a structured laser beam. It shows that these materials are highly sensitive to the polarization state of the illuminating beam and can be used to create non-uniform patterns by adjusting the polarization distribution.
Article
Optics
Victor V. V. Kotlyar, Alexey A. A. Kovalev, Alexey M. M. Telegin
Summary: Based on the Richards-Wolf formalism, two different exact expressions for the angular momentum (AM) density of light in the focus of an optical vortex with right circular polarization are obtained. One expression is derived as the cross product of the position vector and the Poynting vector and has a nonzero value in the focus for any integer n. The other expression is equal to a sum of the orbital angular momentum (OAM) and the spin angular momentum (SAM) and equals zero at n = -1. These expressions are not equal at each point in space, but their 3D integrals are equal. Thus, exact expressions for the AM, SAM, and OAM densities in the focus of an optical vortex are derived, and the identity for the densities AM = SAM + OAM is proven to be invalid. Additionally, the expressions for the strength vectors of the electric and magnetic field near the tight focus, obtained based on the Richards-Wolf formalism, are shown to be exact solutions of Maxwell's equations. Therefore, the Richards-Wolf theory accurately describes the behavior of light near the tight focus in free space.
Article
Optics
Sergey S. S. Stafeev, Vladislav D. D. Zaitsev, Victor V. V. Kotlyar
Summary: This paper investigates the focusing of circularly polarized light with flat diffractive lenses using the Richards-Wolf equations. The study shows that as the numerical aperture (NA) of the lens increases, the size of the focal spot first decreases and then begins to grow. Replacing the flat diffractive lens with an aplanatic lens results in a monotonic decrease in the size of the focal spot as the numerical aperture increases. At the focus of a circularly polarized laser beam, different radius circles with opposite polarization rotation are observed, which may represent the radial spin Hall effect at the focus.
Article
Optics
Svetlana N. Khonina, Alexey P. Porfirev
Summary: We investigate new types of laser beams with autofocusing, rotating, and/or transformation properties theoretically, numerically, and experimentally. Using a spatial light modulator, we generate clusters/sets of shifted vortex Laguerre-Gaussian beams and their superpositions with additional phase distribution, thus forming rotating beam clusters with controlled individual autofocusing trajectories and complex structures. Furthermore, we explore the possibility of astigmatic transformation of the propagating laser beam clusters. These techniques provide additional control of the three-dimensional trajectories of structured laser beams and have applications in laser manipulation, laser material processing, and optical microscopy.
APPLIED PHYSICS B-LASERS AND OPTICS
(2023)
Review
Engineering, Electrical & Electronic
A. Porfirev, S. Khonina, A. Kuchmizhak
Summary: The orbital angular momentum (OAM) of light, which represents the dynamical rotation of a wavefront, is a crucial characteristic of structured electromagnetic fields. Research on the interaction between OAM and matter, initiated in 1992, has led to important advancements in various fields, including physics, chemistry, and biology. This review summarizes recent progress in areas such as laser material processing, optical tweezers, control of chirality, and various OAM-empowered linear and nonlinear effects. It also highlights the remarkable opportunities for modifying ultrahigh-intensity laser-plasma interactions at the atomic scale, as well as the potential applications of spatiotemporal optical vortices.
PROGRESS IN QUANTUM ELECTRONICS
(2023)
Article
Chemistry, Analytical
Victor V. Kotlyar, Alexey A. Kovalev, Elena S. Kozlova, Alexey M. Telegin
Summary: This article investigates the tight focusing of an optical vortex with an integer topological charge and linear polarization. It is shown that the longitudinal components of the spin angular momentum (SAM) and orbital angular momentum (OAM) are preserved separately, leading to the spin and orbital Hall effects. The total energy flux crossing the focus plane is found to be less than the total beam power, and the longitudinal component of the angular momentum vector is not equal to the sum of SAM and OAM. The distributions of the angular momentum and the SAM longitudinal components characterize the orbital and spin Hall effects at the focus, respectively.
Article
Chemistry, Analytical
Alexey A. Kovalev, Victor V. Kotlyar, Sergey S. Stafeev
Summary: We investigated a paraxial vectorial Gaussian beam with multiple polarization singularities residing on a circle. Despite initial linear polarization, on propagation in space, alternating areas with a spin angular momentum (SAM) density of opposite sign are generated, manifesting the spin Hall effect. We derived that maximal SAM magnitude is on a certain-radius circle in each transverse plane and obtained an approximate expression for the distance to the transverse plane with the maximal SAM density. Furthermore, we defined the singularities circle radius, at which the achievable SAM density is maximal. The obtained results have potential applications in designing micromachines with optically driven elements.
Article
Chemistry, Analytical
Eugeny G. Abramochkin, Victor V. Kotlyar, Alexey A. Kovalev
Summary: We have derived a transformation method that relates standard Bessel-Gaussian (BG) beams with BG beams described by a Bessel function of a half-integer order and quadratic radial dependence. We have also studied square vortex BG beams described by the square of the Bessel function and double-BG beams described by a product of two different integer-order Bessel functions. By deriving expressions as series of products of three Bessel functions, we have described the propagation of these beams in free space. Additionally, we have obtained a vortex-free power-function BG beam and explored its propagation characteristics.
Article
Chemistry, Analytical
Alexey A. Kovalev, Victor V. Kotlyar
Summary: We study the spin angular momentum (SAM) of double-index cylindrical vector beams in tight focus. We generalize the conventional cylindrical vector beams by considering different polarization orders for the transverse field components. Based on the Richards-Wolf theory, we derive the SAM distribution and find that the spin Hall effect occurs in the tight focus when the polarization orders have different parity. We also analyze the orbital angular momentum spectrum and predict the SAM distribution, demonstrating the ability to generate focal distributions with alternating areas of positive and negative spin angular momentum.
Article
Optics
A. G. Nalimov, V. V. Kotlyar
Summary: A combined high-aperture metalens in a thin silicon nitride film composed of two inclined sector metalens, each consisting of binary subwavelength gratings, is capable of detecting optical vortices with different topological charges and wavelengths. The metalens can distinguish wavelengths focused at different points in the focal plane and has a focal spot shift of approximately 4 nm for a 1 nm change in wavelength. When illuminated by a Gaussian beam with left-handed circular polarization, two optical vortices with topological charges are simultaneously formed at a focal distance of 6 nm.
Article
Chemistry, Multidisciplinary
Sergey S. Stafeev, Nikita N. Kazakov, Vladislav D. Zaitsev, Sergey D. Poletayev, Victor V. Kotlyar
Summary: In this work, the tight focusing of vector beams with azimuthal polarization and beams with a V-line of polarization singularity was numerically simulated using the Richards-Wolf formulas. It was found that in a tight focus for these beams, there is no longitudinal component of the electric field. Calculation of the longitudinal component of the spin angular momentum was performed, and the possibility of creating sector azimuthally polarized beams using vector waveplates was demonstrated.
APPLIED SCIENCES-BASEL
(2023)
