Editorial

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4 pages, 177 KiB

Open AccessEditorial

Special Issue on Light Control and Particle Manipulation: An Overview

by Zhe Shen

Photonics 2023, 10(11), 1213; https://doi.org/10.3390/photonics10111213 - 31 Oct 2023

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Abstract

Since Dr [...] Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

Research

Jump to: Editorial, Review

10 pages, 2850 KiB

Open AccessCommunication

Enhanced Spin Hall Shift by Multipoles of Different Orders in Spherical Particles

by Rudao Li, Dongliang Gao and Lei Gao

Photonics 2023, 10(7), 732; https://doi.org/10.3390/photonics10070732 - 26 Jun 2023

Cited by 1 | Viewed by 697

Abstract

The spin–orbit interaction of light is universal in the process of light scattering, and an important aspect is the spin Hall effect. The spin Hall effect of light also exists in a three-dimensional (3D) system. When circularly polarized light is incident on a [...] Read more.

The spin–orbit interaction of light is universal in the process of light scattering, and an important aspect is the spin Hall effect. The spin Hall effect of light also exists in a three-dimensional (3D) system. When circularly polarized light is incident on a spherical particle, the transverse displacement of the particle relative to the scattering plane can be observed due to the spiraling of the Poynting vector in the far field. In general, the spin Hall shift of light is negligible and difficult to detect in experiments. In this paper, we use a high-refractive-index (HRI) core-shell structure to excite high-order multipoles and explore the interaction between different order multipoles to enhance the spin Hall shift in the microwave band. We show that there exist some angles that increase the spin Hall shift when two particular multipoles are equal and dominated. Our work provides a new perspective for understanding the interaction between light and particles and enhances the spin Hall shift of the sphere in the microwave band. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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13 pages, 10690 KiB

Open AccessArticle

Flexible Terahertz Metamaterials Absorber based on VO₂

by Zhaoxia Jiang, Jin Leng, Jin Li, Jianfei Li, Boyang Li, Mao Yang, Xiaolian Wang and Qiwu Shi

Photonics 2023, 10(6), 621; https://doi.org/10.3390/photonics10060621 - 28 May 2023

Cited by 1 | Viewed by 1614

Abstract

Terahertz (THz) metamaterials have attracted great attention due to their widely application potential in smart THz devices; however, most of them are fabricated on rigid substrate and thus limit the exploration of flexible THz electronics. In this paper, a flexible THz metamaterial absorber [...] Read more.

Terahertz (THz) metamaterials have attracted great attention due to their widely application potential in smart THz devices; however, most of them are fabricated on rigid substrate and thus limit the exploration of flexible THz electronics. In this paper, a flexible THz metamaterial absorber (MMA) incorporated with phase change material vanadium dioxide (VO₂) is proposed. The simulation results indicate that two absorption peaks at around 0.24 THz (marked as A) and 0.46 THz (marked as B) can be observed by designing a I-shaped metamaterial combined with split ring structure. The strong absorption over 92% at 0.24 THz is bending-insensitive, but the absorption at 0.46 THz is bending-sensitive, across the bending angle in the range of 0–50 degrees. Moreover, dynamic modulation of the absorption can be achieved across the insulator-metal phase transition of VO₂. Particularly, the absorption of the A-peak can be tuned from 99.4% to 46.9%, while the absorption of the B-peak can be tuned from 39.6% to 99.3%. This work would provide significance for the design of flexible THz smart devices. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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11 pages, 2874 KiB

Open AccessEditor’s ChoiceCommunication

Valley-Selective Polarization in Twisted Bilayer Graphene Controlled by a Counter-Rotating Bicircular Laser Field

by Jiayin Chen, Candong Liu and Ruxin Li

Photonics 2023, 10(5), 516; https://doi.org/10.3390/photonics10050516 - 01 May 2023

Cited by 5 | Viewed by 1501

Abstract

The electron valley pseudospin in two-dimensional hexagonal materials is a crucial degree of freedom for achieving their potential application in valleytronic devices. Here, bringing valleytronics to layered van der Waals materials, we theoretically investigate lightwave-controlled valley-selective excitation in twisted bilayer graphene (tBLG) with [...] Read more.

The electron valley pseudospin in two-dimensional hexagonal materials is a crucial degree of freedom for achieving their potential application in valleytronic devices. Here, bringing valleytronics to layered van der Waals materials, we theoretically investigate lightwave-controlled valley-selective excitation in twisted bilayer graphene (tBLG) with a large twist angle. It is demonstrated that the counter-rotating bicircular light field, consisting of a fundamental circularly-polarized pulse and its counter-rotating second harmonic, can manipulate the sub-cycle valley transport dynamics by controlling the relative phase between two colors. In comparison with monolayer graphene, the unique interlayer coupling of tBLG renders its valley selectivity highly sensitive to duration, leading to a noticeable valley asymmetry that is excited by single-cycle pulses. We also describe the distinct signatures of the valley pseudospin change in terms of observing the valley-selective circularly-polarized high-harmonic generation. The results show that the valley pseudospin dynamics can still leave visible fingerprints in the modulation of harmonic signals with a two-color relative phase. This work could assist experimental researchers in selecting the appropriate protocols and parameters to obtain ideal control and characterization of valley polarization in tBLG. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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12 pages, 4544 KiB

Open AccessArticle

Generation and Manipulation of Airy Breathing Solitons in an Inhomogeneous Medium with Periodic Potential

by Chunhui Gao, Bing Wen, Yangbao Deng, Yingqi Fan, Jiamou Wei and Depeng Chen

Photonics 2023, 10(5), 486; https://doi.org/10.3390/photonics10050486 - 24 Apr 2023

Cited by 1 | Viewed by 1072

Abstract

The propagation characteristics of Airy beams in an inhomogeneous medium with periodic potential are studied theoretically and numerically. The Gross–Pitaevskii equation was solved with periodic potential using the separating variables method, and a breathing soliton solution and the breathing period were obtained. Further, [...] Read more.

The propagation characteristics of Airy beams in an inhomogeneous medium with periodic potential are studied theoretically and numerically. The Gross–Pitaevskii equation was solved with periodic potential using the separating variables method, and a breathing soliton solution and the breathing period were obtained. Further, the propagation properties of an Airy beam, and the interaction between two Airy beams while considering the medium parameters and beam parameters were numerically simulated in detail. First, we discuss the influence of the initial medium parameters (modulation intensity P and modulation frequency ω) on the propagation characteristics. Then, we investigate the effect of the initial beam parameters (initial chirp C and position x₀) on the propagation characteristics. Lastly, the interaction of two Airy beams with opposite spatial positions for different phase φ, amplitude A, and initial interval x₀ is analyzed. The breathing period and central position of the breathing solitons could be controlled by changing the initial medium parameters. By varying the initial beam parameters, the deflection direction and size, and the maximal intensity of the breathing solitons were manipulated. The breathing solitons of different bound states were formed by changing the phase φ, amplitude A, and initial interval x₀ of two Airy beams. The results provide a theoretical basis for the propagation and manipulation of Airy beams. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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10 pages, 2544 KiB

Open AccessCommunication

Particle Trapping Properties of Metal Annular Slits under Vector Field Excitation

by Chunyan Bai, Jiqing Lian, Xiangcai Ma, Peizhen Qiu, Dileep Kumar and Saima Kanwal

Photonics 2023, 10(4), 445; https://doi.org/10.3390/photonics10040445 - 13 Apr 2023

Cited by 1 | Viewed by 1094

Abstract

This article presents the particle capture performance of annular slits, which offer a simple alternative to complex micro/nano structures used to excite and focus surface plasmon polaritons (SPPs). Additionally, the annular slits are compatible with a variety of vector light fields, generating diverse [...] Read more.

This article presents the particle capture performance of annular slits, which offer a simple alternative to complex micro/nano structures used to excite and focus surface plasmon polaritons (SPPs). Additionally, the annular slits are compatible with a variety of vector light fields, generating diverse SPP field distributions under their excitation. These SPP fields can be regulated by varying the vector light field parameters, thereby offering the annular slit structure the ability to flexibly capture and manipulate particles. The rotation and movement of captured objects can be achieved by changing the position and phase difference of the incident beams with linear polarization. Different material and sized metallic particles can be stably captured with a radially polarized beam excitation due to the strong convergence. These capabilities are demonstrated by evaluating the optical force and trapping potential based on the finite difference time domain (FDTD) simulation. This study provides valuable insights into the practical application of annular slits for particle capture and manipulation. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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15 pages, 20803 KiB

Open AccessArticle

Polarization-Independent Ultra Wideband RCS Reduction Conformal Coding Metasurface Based on Integrated Polarization Conversion-Diffusion-Absorption Mechanism

by Hamza Asif Khan, Umair Rafique, Syed Muzahir Abbas, Fahad Ahmed, Yifei Huang, Junaid Ahmed Uqaili and Abdelhady Mahmoud

Photonics 2023, 10(3), 281; https://doi.org/10.3390/photonics10030281 - 07 Mar 2023

Cited by 6 | Viewed by 1855

Abstract

An ultra wideband (UWB) radar cross-section (RCS) reduction metasurface has received attention in recent years. However, the majority of the research has concentrated on the physics and design of planar surfaces, which do not meet the standards of modern aerodynamics and aesthetics. In [...] Read more.

An ultra wideband (UWB) radar cross-section (RCS) reduction metasurface has received attention in recent years. However, the majority of the research has concentrated on the physics and design of planar surfaces, which do not meet the standards of modern aerodynamics and aesthetics. In this paper, we offer a sophisticated strategy for designing a metasurface that can conform to the shape of any object, even those of moderate curvature, and can also achieve UWB RCS reduction by combining absorption, polarization conversion, and diffusion mechanisms. Firstly, an absorbing-polarization converter is designed, composed of a square patch with a truncated diagonal strip and ring. A thin Rogers RT/Duroid 5880 dielectric substrate layer is used in the structure, which is also appropriate for conformal conditions. The substrate layer and the ground plane are separated by an air gap to enhance the polarization conversion bandwidth (PCBW). For normal incident electromagnetic (EM) waves, the PCBW ranges from 10.8 to 31.3 GHz with polarization conversion ratio (PCR) values greater than 0.9 dB. Up to a 45

^{\circ}

oblique incidence angle over the aforementioned band, the PCR efficiency is well maintained. Then, the optimized coding metasurface is formed by the Pancharatnam–Berry (PB) phase, consisting of meta-atoms “0” and “1” of the same size but different orientations, to realize the concept of cross-polarization diffusion. A theoretical investigation has been performed to analyze the RCS reduction performance of planar as well as conformal cylindrical surfaces. The results show that more than 10 dB of RCS reduction is experienced over UWB (10.8–31.3 GHz) for planar metasurfaces under linearly and circularly polarized incidence waves. Furthermore, the RCS reduction for cylindrical surfaces can be achieved in a similar frequency band above 10 dB up to an angle of 90

^{\circ}

. It can be deduced that our proposed flexible metasurface can be used as an absorber or a polarization converter and provide broadband RCS reduction, which is essential for multi-function and conformal stealth applications. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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20 pages, 13811 KiB

Open AccessArticle

Development of 3D Microstructures for the Formation of a Set of Optical Traps on the Optical Axis

by Dmitry A. Savelyev and Sergey V. Karpeev

Photonics 2023, 10(2), 117; https://doi.org/10.3390/photonics10020117 - 22 Jan 2023

Cited by 5 | Viewed by 1557

Abstract

Three-dimensional (3D) microstructures used in the formation of optical traps on the optical axis in the near diffraction zone are calculated and studied. Subwavelength, variable-height annular gratings (a lattice period of 1.05λ) with a standard and graded-index (GRIN) substrate are considered as microstructures. [...] Read more.

Three-dimensional (3D) microstructures used in the formation of optical traps on the optical axis in the near diffraction zone are calculated and studied. Subwavelength, variable-height annular gratings (a lattice period of 1.05λ) with a standard and graded-index (GRIN) substrate are considered as microstructures. Two scenarios are examined for changing the refractive index n of the GRIN substrate: from a maximum n in the center to a minimum n at the edges (direct GRIN) and, conversely, from a minimum n in the center to a maximum n at the edges (reverse GRIN). The propagation of light through the proposed 3D microstructures is simulated using the finite-difference time-domain (FDTD) method. The possibility of obtaining not only single but also a set of optical traps on the optical axis is demonstrated. It is also shown that compared to the results obtained with a diffractive axicon, the size of the focal spot can be reduced by 21.6% when use is made of the proposed 3D microstructures and the light needle is increased by 2.86 times. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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11 pages, 3086 KiB

Open AccessCommunication

Visible to Mid-Infrared Supercontinuum Initiated by Stimulated Raman Scattering of 1.03 μm Ultrashort Pulses in a Gas-Filled Silica Fiber

by Alexey Gladyshev, Yury Yatsenko, Anton Kolyadin and Igor Bufetov

Photonics 2022, 9(12), 997; https://doi.org/10.3390/photonics9120997 - 17 Dec 2022

Cited by 7 | Viewed by 1199

Abstract

Multiband supercontinuum generation covering the bandwidth from 0.65 μm to 3.3 μm was demonstrated in a gas-filled hollow-core silica fiber pumped by chirped ultrashort pulses at 1.03 μm. The development of the SC spectrum into the mid-IR was initiated by cascade stimulated Raman [...] Read more.

Multiband supercontinuum generation covering the bandwidth from 0.65 μm to 3.3 μm was demonstrated in a gas-filled hollow-core silica fiber pumped by chirped ultrashort pulses at 1.03 μm. The development of the SC spectrum into the mid-IR was initiated by cascade stimulated Raman scattering in gaseous D₂, which was used as an active medium filling the hollow core. The influence of the Kerr nonlinearity was studied by changing the linear chirp of the pump pulses. The influence of gas pressure and pump pulse energy on the SC generation was investigated. As high as 14% of pump quanta were converted to the wavelength range above 2 μm. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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11 pages, 2405 KiB

Open AccessArticle

Photonic Crystal Fiber Sensor for Detecting Sulfuric Acid in Different Concentrations

by Abdul Mu’iz Maidi, Md. Abul Kalam and Feroza Begum

Photonics 2022, 9(12), 958; https://doi.org/10.3390/photonics9120958 - 09 Dec 2022

Cited by 8 | Viewed by 1106

Abstract

A high-performance photonic crystal fiber sensor for sulfuric acid detection is designed and investigated, undertaken through a full vector Finite Element Method on COMSOL Multiphysics software to establish the optical properties of effective refractive index, power fraction, relative sensitivity, confinement loss, chromatic dispersion, [...] Read more.

A high-performance photonic crystal fiber sensor for sulfuric acid detection is designed and investigated, undertaken through a full vector Finite Element Method on COMSOL Multiphysics software to establish the optical properties of effective refractive index, power fraction, relative sensitivity, confinement loss, chromatic dispersion, and propagation constant. Different aqueous sulfuric acid concentrations of 0%, 10%, 20%, 30%, and 40% were selected as the test analytes. The dimensions of two cladding rings of the hexagon- and circular-shaped air holes and a circular core hole denoted outstanding outcomes of relative sensitivity and confinement loss. At 1.1 µm optimum wavelength, 0%, 10%, 20%, 30%, and 40% sulfuric acid concentrations depict relative sensitivities of 97.08%, 97.67%, 98.06%, 98.39%, and 98.67%, respectively, and confinement losses of 1.32 × 10⁻¹² dB/m, 4.11 × 10⁻¹² dB/m, 1.46 × 10⁻¹² dB/m, 6.34 × 10⁻¹² dB/m, and 2.12 × 10⁻¹² dB/m, respectively. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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14 pages, 3198 KiB

Open AccessArticle

Transfer of Orbital Angular Momentum of Light Using Autler-Townes Splitting

by Seyyed Hossein Asadpour, Hamid Reza Hamedi and Emmanuel Paspalakis

Photonics 2022, 9(12), 954; https://doi.org/10.3390/photonics9120954 - 09 Dec 2022

Cited by 8 | Viewed by 1226

Abstract

We propose a scheme to exchange optical vortices beyond electromagnetically induced transparency (EIT) but based on four-wave mixing (FWM) in a five-level atomic system consisting of two

Λ

subsystems linked via a weak driving field. When the laser fields are strong enough, the [...] Read more.

We propose a scheme to exchange optical vortices beyond electromagnetically induced transparency (EIT) but based on four-wave mixing (FWM) in a five-level atomic system consisting of two

Λ

subsystems linked via a weak driving field. When the laser fields are strong enough, the quantum interference responsible for the EIT in each

Λ

subsystem is washed out, giving rise to the Autler-Townes splitting (ATS). When only one of the control fields carries an optical vortex, it is shown that the generated FWM field obtains the vorticity of the vortex control. We distinguish between three different regimes, i.e., a pure EIT, a joint EIT-ATS, and a dual-ATS, where the optical angular momentum (OAM) translation can take place. Elaborating on the distinction between three regimes through numerical analysis, we find that the maximum energy conversion efficiency is obtained in the joint EIT-ATS and dual-ATS regimes. The latter is more favorable as the absorption losses vanish as the beam propagates into the atomic cloud. The results may find applications in the implementation of high-efficient frequency and OAM conversion devices for quantum information processing. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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15 pages, 3374 KiB

Open AccessArticle

Research on a MEMS Microparticles Vacuum Chamber for Optical Levitation with a Built-In Vacuum Gauge

by Junji Pu, Kai Zeng, Yulie Wu and Dingbang Xiao

Photonics 2022, 9(12), 911; https://doi.org/10.3390/photonics9120911 - 28 Nov 2022

Cited by 2 | Viewed by 1354

Abstract

The vacuum chamber is an important part of microparticle optical levitation technology. The traditional vacuum chamber has a large volume and many peripheral components, which cannot meet the requirements of miniaturization and on-chip optical levitation technology. Therefore, this study proposes a novel microparticle [...] Read more.

The vacuum chamber is an important part of microparticle optical levitation technology. The traditional vacuum chamber has a large volume and many peripheral components, which cannot meet the requirements of miniaturization and on-chip optical levitation technology. Therefore, this study proposes a novel microparticle vacuum chamber based on the micro-electro-mechanical system (MEMS) process. This MEMS microparticle vacuum chamber adopts a “glass-silicon-glass” three-layer vacuum bonding process, with a volume of only 15 mm × 12 mm × 1.2 mm, including particle chamber, cantilever resonator chamber, and getter chamber, which can encapsulate microparticles in a tiny vacuum environment and realize optical levitation of microparticles. At the same time, the air pressure in the micro vacuum chamber is monitored by the cantilever resonator, which can provide a miniaturized microparticle chamber with a more accurate vacuum environment for microparticle optical levitation. The research of this paper has significance for promoting the development of miniaturized optical levitation technology. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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10 pages, 3907 KiB

Open AccessCommunication

Plasmonic Surface Lattice Resonances in Suspended Symmetric Double-Layer Gratings

by Mengjia Cen, Jiawei Wang, Jianxun Liu, Ye Li, Wenfeng Cai, Delai Kong, Dan Luo, Tun Cao and Yan Jun Liu

Photonics 2022, 9(12), 890; https://doi.org/10.3390/photonics9120890 - 22 Nov 2022

Cited by 2 | Viewed by 1547

Abstract

Surface lattice resonances (SLRs) with high-quality factors supported by metal nanoparticle arrays are useful for plasmonic nanolasers, biochemical sensors, and surface-enhanced Raman spectroscopy. Most nanoparticle arrays are fabricated on a substrate, and the refractive index mismatch between the substrate and superstrate suppresses the [...] Read more.

Surface lattice resonances (SLRs) with high-quality factors supported by metal nanoparticle arrays are useful for plasmonic nanolasers, biochemical sensors, and surface-enhanced Raman spectroscopy. Most nanoparticle arrays are fabricated on a substrate, and the refractive index mismatch between the substrate and superstrate suppresses the performance of SLRs. In this work, we propose unique SLRs excited in suspended, self-aligned symmetric double-layer gratings with index-matched environment. The self-aligned double-layer gratings are fabricated using a single-step electron beam lithography and exhibit a Fano-like spectra resulting from interference between out-of-plane plasmonic resonances and diffraction modes. By changing the incident angle and refractive index of the surrounding medium, the SLRs can be tuned from visible to near-infrared regions with a high-quality factor of 120. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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6 pages, 2464 KiB

Open AccessArticle

Van Der Waals Materials for Subdiffractional Light Guidance

by Georgy Ermolaev, Dmitriy Grudinin, Kirill Voronin, Andrey Vyshnevyy, Aleksey Arsenin and Valentyn Volkov

Photonics 2022, 9(10), 744; https://doi.org/10.3390/photonics9100744 - 09 Oct 2022

Cited by 8 | Viewed by 1482

Abstract

Photonics is a natural next technological step after an era of electronics. However, the diffraction limit of light poses severe limitations on photonic elements and dictates their size. Herein, we demonstrate that layered semiconductors solve this challenge thanks to their giant optical anisotropy. [...] Read more.

Photonics is a natural next technological step after an era of electronics. However, the diffraction limit of light poses severe limitations on photonic elements and dictates their size. Herein, we demonstrate that layered semiconductors solve this challenge thanks to their giant optical anisotropy. In particular, waveguides with molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂) claddings can operate in a transparency region slightly above (20%) the diffraction limit and even overcome it by 10% around 700 nm, providing an even better confinement than air cladding, but with excitonic losses. Further analysis reveals that van der Waals materials with an in-plane refractive index of about five or an out-of-plane index around two provide subdiffractional and lossless guidance. Therefore, our results establish the route for ultra-dense photonic integration based on layered materials. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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13 pages, 5139 KiB

Open AccessArticle

Effect of Twisting Phases on the Polarization Dynamics of a Vector Optical Field

by Quanbin Liu, Khian-Hooi Chew, Yingqi Huang, Caixia Liu, Xiaobo Hu, Yuhua Li and Rui-Pin Chen

Photonics 2022, 9(10), 722; https://doi.org/10.3390/photonics9100722 - 04 Oct 2022

Cited by 7 | Viewed by 1163

Abstract

The effect of twisting phases on the polarization dynamics of a vector vortex beam with a spatially variant state of polarization (SoP) is investigated theoretically and experimentally. The twisted vector vortex optical field with the cross-phase modulation is experimentally generated and observed. The [...] Read more.

The effect of twisting phases on the polarization dynamics of a vector vortex beam with a spatially variant state of polarization (SoP) is investigated theoretically and experimentally. The twisted vector vortex optical field with the cross-phase modulation is experimentally generated and observed. The presence of the twisting phases on the vector optical field results in novel propagation dynamics and the evolution of polarization states. The optical field performs the process of compressing and stretching the orthogonal polarization components and the linear-circular polarization conversions during propagation. Different from the scalar twisted beams, the orthogonal polarization components of twisted vector beams can be compressed along the same azimuthal angle or the orthogonal azimuthal angles, depending on the signs of the twist intensity coefficients. For an anisotropic twisted optical field, the SoP and the optical field rotate, and the rotation behaviors are sensitively dependent on the twisting coefficients. Furthermore, the two vortex topological charges embedded within the orthogonal polarization component of a twisted vector vortex beam can be simultaneously identified by looking at the interference fringes of the twisting phases. This work reveals that a vector vortex beam and its SoP can be dynamically manipulated by twisting phases. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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11 pages, 773 KiB

Open AccessArticle

Detection Optimization of an Optically Trapped Microparticle in Vacuum with Kalman Filter

by Shidong Xu, Ming Chen, Jianyu Yang, Xingfan Chen, Nan Li and Huizhu Hu

Photonics 2022, 9(10), 700; https://doi.org/10.3390/photonics9100700 - 27 Sep 2022

Cited by 1 | Viewed by 1302

Abstract

The optical trapping of micro-nano particles in a high vacuum has become a popular research platform in various frontier fields of physics because of its excellent isolation from the environment. The precise measurement of particle motion information is required to analyze and control [...] Read more.

The optical trapping of micro-nano particles in a high vacuum has become a popular research platform in various frontier fields of physics because of its excellent isolation from the environment. The precise measurement of particle motion information is required to analyze and control particle motion modes in traps. However, the detection accuracy is limited by measurement noise and coupling signals from other axes in microparticle optical traps. In this study, we use the Kalman filter to extract the real motion information of each axis under simulation conditions, and the results show that the Kalman filter performs well in noise suppression, improving the RMSE from 12.64 to 5.18 nm and enhancing the feedback cooling performance by approximately 27% through reducing the axes’ signal coupling ratio. We believe that as a solution to these challenges, the Kalman filter will bring a significant achievement to micrometer particle optical traps in vacuums. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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18 pages, 2426 KiB

Open AccessArticle

Generation of Elliptic-Symmetry Radially Polarized Optical Beam by Circle-Cassinian Optical Coordinate Transformation

by Huan Wei and Hui Fang

Photonics 2022, 9(8), 563; https://doi.org/10.3390/photonics9080563 - 11 Aug 2022

Cited by 1 | Viewed by 1499

Abstract

Recently, optical coordinate transformation has garnered considerable research interest for manipulating structured light in emerging optical communication applications. Herein, we propose a circle-Cassinian optical coordinate transformation based on polarization invariance to generate an elliptical-symmetry radially polarized (ESRP) optical beam. Accordingly, we designed three [...] Read more.

Recently, optical coordinate transformation has garnered considerable research interest for manipulating structured light in emerging optical communication applications. Herein, we propose a circle-Cassinian optical coordinate transformation based on polarization invariance to generate an elliptical-symmetry radially polarized (ESRP) optical beam. Accordingly, we designed three isotropic phase plates for placement in the 4f optical system. The numerical simulations demonstrated accurate generation of the ESRP beam with specified intensity, including an overall intensity adjustment applied in the input plane. Therefore, the proposed method can aid in designing vector light fields, and the ESRP beam can be applied to optical tweezers and surface plasmonic-field generation. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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Jump to: Editorial, Research

21 pages, 5151 KiB

Open AccessReview

A Review of Optical Tweezers with Metasurfaces

by Zhe Shen and Xinyu Huang

Photonics 2023, 10(6), 623; https://doi.org/10.3390/photonics10060623 - 28 May 2023

Cited by 4 | Viewed by 2206

Abstract

Optical tweezers (OTs) have made significant progress in recent years, realizing the non-contact optical manipulation of target objects through the interaction between light and matter. In addition to trapping particles with the intensity gradient of the beam, a series of complex optical elements [...] Read more.

Optical tweezers (OTs) have made significant progress in recent years, realizing the non-contact optical manipulation of target objects through the interaction between light and matter. In addition to trapping particles with the intensity gradient of the beam, a series of complex optical elements are required to properly modulate the beams to expand the operation of optical manipulation. The development of metasurfaces alleviates this problem. Due to the merits of miniaturization, planarization, multi-function, and integration of metasurfaces, these kinds of novel devices have been applied in OT systems. Metasurface devices have been used to replace traditional objective lenses, achieving device integration and even obtaining multi-function of OTs with unique optical properties in applications. OTs with metasurfaces have developed rapidly, and a great deal of work has been carried out on OTs with metasurfaces, as well as discussions on their practical applications. In this review, we regard the latest progress in the field of OTs with metasurfaces. We classify OTs with metasurface and summarize the new impetus brought by metasurfaces for the development of OTs. Full article

(This article belongs to the Special Issue Light Control and Particle Manipulation)

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