Two-dimensional Manipulation Research Articles

Autofocusing capabilities of double-ring circular Airy Gaussian beams and their application in particle manipulation

Focusing is extensively researched in bioimaging, medicine, and quantum computation. However, single focal point and short focal length restrict imaging and optical manipulation at long distances. In this study, we propose what we believe to be a novel method, namely the coherent superposition of double-ring circular Airy Gaussian beams (DR-CAiGBs) to achieve multiple autofocusing over long distances. Without complex structures, theoretical simulations and experimental verifications demonstrate that the DR-CAiGBs can generate multiple autofocusing points along the optical axis, whose positions and quantities can be flexibly adjusted. Furthermore, we demonstrated the two-dimensional (2D) particle manipulation of the DR-CAiGBs by trapping multiple particles at different autofocusing points over 100 µm. Our research and findings establish new avenues for practical applications in biological cell analysis, particle transportation, and lithography.

Motion Planning for Dynamic Three-Dimensional Manipulation for Unknown Flexible Linear Object

Generally, deformable objects have large and nonlinear deformations. Because of these characteristics, recognition and estimation of their movement are difficult. Many studies have been conducted aimed at manipulating deformable objects at will. However, they have been focused on situations wherein a rope’s properties are already known from prior experiments. In our previous work, we proposed a motion planning algorithm to manipulate unknown ropes using a robot arm. Our approach considered three steps: motion generation, manipulation, and parameter estimation. By repeating these three steps, a parameterized flexible linear object model that can express the actual rope movements was estimated, and manipulation was realized. However, our previous work was limited to 2D space manipulation. In this paper, we extend our previously proposed method to address casting manipulation in a 3D space. Casting manipulation involves targeting the flexible linear object tips at the desired object. While our previous studies focused solely on two-dimensional manipulation, this work examines the applicability of the same approach in 3D space. Moreover, 3D manipulation using an unknown flexible linear object has never been reported for dynamic manipulation with flexible linear objects. In this work, we show that our proposed method can be used for 3D manipulation.

Selection of functional sperm by using hyaluronic acid modified magnetic microbeads and an electromagnetic manipulation system.

In recent years, the incidence of infertility has increased year by year. Assisted reproductive technology (ART) is one of the effective strategies to treat infertility. In the process of ART, commonly used methods for sperm separation have shortcomings and there is still room for improvement. In this study, a functional sperm selection strategy was established based on hyaluronic acid (HA) modified magnetic microbeads (MBs) and a supporting two-dimensional electromagnetic manipulation device system. Due to the modification of HA on the surface of MBs, the HA-MBs have the ability to target and bind to specific receptors on the sperm membrane to form a sperm-MB complex. A disulfide linker was introduced to connect HA and MBs. After modifying HA and connecting it with the disulfide linker, the sperm of sperm-MBs can be released under the combined effect of hyaluronidase and reduced GSH with the disulfide bond broken and HA degraded. A two-dimensional electromagnetic manipulation system was introduced to generate a magnetic field and control the directional movement of the sperm-MB complex under the guidance of an inverted microscope. The free MBs can also be removed after the sperm is released. Furthermore, the mouse sperm selected through this strategy can achieve normal insemination via ICSI and the obtained blastocysts have normal morphology and developmental milestones. This strategy has potential to be developed into an automated screening solution for the screening of functional sperm for assisted reproductive technology.

High quality factor metasurfaces for two-dimensional wavefront manipulation

The strong interaction of light with micro- and nanostructures plays a critical role in optical sensing, nonlinear optics, active optical devices, and quantum optics. However, for wavefront shaping, the required local control over light at a subwavelength scale limits this interaction, typically leading to low-quality-factor optical devices. Here, we demonstrate an avenue towards high-quality-factor wavefront shaping in two spatial dimensions based on all-dielectric higher-order Mie-resonant metasurfaces. We design and experimentally realize transmissive band stop filters, beam deflectors and high numerical aperture radial lenses with measured quality factors in the range of 202–1475 at near-infrared wavelengths. The excited optical mode and resulting wavefront control are both local, allowing versatile operation with finite apertures and oblique illumination. Our results represent an improvement in quality factor by nearly two orders of magnitude over previous localized mode designs, and provide a design approach for a new class of compact optical devices.

Geometric phase and photonic spin Hall effect in thin films with architected columnar morphology

We have detected spin-dependent splitting of light, the signature of the photonic spin Hall effect (PSHE), via quantum weak measurements on two types of thin films with architected columnar morphology. Specifically, we fabricated columnar thin films comprising parallel tilted nanocolumns and chiral sculptured thin films comprising parallel upright nanohelices by resistively heating zinc selenide (ZnSe) in a low-pressure chamber and collecting the collimated vapor flux of ZnSe on planar substrates with dynamically varying orientation. The architected columnar morphology creates a spin-dependent geometric Pancharatnam–Berry (PB) phase corresponding to the evolution of polarization states on the Poincaré sphere. Morphology-controlled anisotropy and spatial inhomogeneity result in the depolarization and optical rotation of incident plane-polarized light, and intrinsic spin-precession coupling with the propagation vector, contributing to the efficient generation and two-dimensional manipulation of both in-plane and out-of-plane spin splitting and steering the PB phase in the propagation process. The first experimental observations of widely tailorable PSHE and PB phase in thin films with architected columnar morphology may lead to new applications ranging from spin-controlled nanophotonics to optoelectronic devices for quantum information processing and optical communication.

Acoustic manipulation of microparticles using a two-dimensional phononic crystal plate

Acoustic waves can manipulate particles without contact or damage, and has received increasing attention due to their potential applications in various fields, such as cell sorting, organoid construction, and material assembly. In general, high-throughput manipulation of microparticles relies on a large number of active transducers and phase-shifting circuits to create standing wave patterns, thus significantly inducing system complexity. Recently, we realized the parallel manipulation of microparticles by using an acoustic field modulated by a one-dimensional phononic crystal plate. The concept is based on the fact that phononic crystal plate can resonantly excite the zero-order asymmetric (<i>A</i><sub>0</sub>) Lamb wave, inducing highly localized periodic radiation force on the particles. In this paper, we further show that by using a two-dimensional phononic crystal plate (TDPCP), parallel manipulation of massive particles can be achieved only with a single transducer. The <i>A</i><sub>0</sub> Lamb wave can be excited by a TDPCP, forming a two-dimensional periodic localized field, and then particles can suffer negative vertical force and stable zero horizontal force, inducing two-dimensional periodic trapping on the surface of the plate. Combining a PZT source with a TDPCP consisting of a brass plate patterned with periodical brass stubs, we observe the capture and arrangement of glass microspheres, achieving two-dimensional arrangement manipulation of particles on the TDPCP. This system represents a significant advancement in developing high-throughput, rapid, and flexible devices for particles and cell manipulation.

Two-dimensional manipulation of ultraviolet Photonic Spin Hall Effect with high efficiency broadband dielectric metasurface

Photonic Spin Hall Effect (PSHE) is a relativistic spin-orbit coupling phenomenon that can provide a wide range of spin-controlled nano-photon applications. However, most of the research results have been achieved only on 1D modulation of PSHE and the PSHE is very weak because of the extremely small spin-orbit interaction. Here, we propose a novel method to achieve a 2D manipulation of PSHE based on the broadband dielectric metasurface with refractive efficiency of above 80%. Using silicon nitride nanorods with perfect half-wave plates properties, a high-efficiency metasurface is designed, which demonstrated that directly realizes the high-performance PSHE in the ultraviolet region. Moreover, the metasurface can realize longitudinal focusing and transverse deflection of photons in different spin states by using the Pancharatnam-Berry (PB) phase and propagation phase, thus enabling 2D flexible manipulation of spin photons. The results show that the broadband dielectric metasurface offers a method to develop a high-efficiency PSHE for generating and manipulating spin-polarized photons, achieving important applications in optical communication, beam shaping, and optical sensors.

Programmable Droplet Microfluidics Based on Machine Learning and Acoustic Manipulation.

Typical microfluidic devices are application-specific and have to be carefully designed to implement the necessary functionalities for the targeted application. Programmable microfluidic chips try to overcome this by offering reconfigurable functionalities, allowing the same chip to be used in multiple different applications. In this work, we demonstrate a programmable microfluidic chip for the two-dimensional manipulation of droplets, based on ultrasonic bulk acoustic waves and a closed-loop machine-learning-based control algorithm. The algorithm has no prior knowledge of the acoustic fields but learns to control the droplets on the fly. The manipulation is based on switching the frequency of a single ultrasonic transducer. Using this method, we demonstrate 2D transportation and merging of water droplets in oil and oil droplets in water, and we performed the chemistry that underlies the basis of a colorimetric glucose assay. We show that we can manipulate drops with volumes ranging from ∼200 pL up to ∼30 nL with our setup. We also demonstrate that our method is robust, by changing the system parameters and showing that the machine learning algorithm can still complete the manipulation tasks. In short, our method uses ultrasonics to flexibly manipulate droplets, enabling programmable droplet microfluidic devices.

Enhancing the Photoinduced Interlayer Charge Transfer and Spatial Separation in Type-II Heterostructure of WS2 and Asymmetric Janus-MoSSe with Intrinsic Self-Build Electric Field

Two-dimensional heterostructure manipulation is promising to overcome the high recombination rates and limited redox abilities of photogenerated electron-hole pairs in a single photocatalyst. The built-in electric field (Ehetero) in the type-II heterojunction is normally unfavorable for the desired charge transfer, which is an important but easily neglected issue that needs to be solved. Here, on the basis of the density functional theory (DFT) and the nonadiabatic molecular dynamics (NAMD) calculations, we obtain a type-II band alignment in Janus-MoSSe/WS2 heterostructure, which meets the band-edge position requirement for water splitting. Importantly, the intrinsic self-build electric field (Eself) of Janus-MoSSe can effectively weaken the hindrance effect of Ehetero for charge transfer by constructing a suitable Se-S stacking configuration, improving charge separation efficiency in the Janus-MoSSe/WS2 heterostructure. Our work provides a materials-by-design paradigm and interlayer charge-transfer dynamics understanding of heterostructure engineering against asymmetric structures lacking reflection symmetry.

Two-dimensional manipulation of droplets on a single-sided continuous optoelectrowetting digital microfluidic chip

Digital microfluidic chips are liquid processors that perform biochemical assays by moving, merging and splitting droplets using the electrowetting effect. Yet, hardwiring electrowetting chips becomes tedious as soon as they include more than a few dozen electrodes. Single-sided continuous opto-electrowetting, where the electrowetting effect of a featureless semiconductor film is controlled by light patterns is a promising solution to this hardwiring bottleneck, but so far two-dimensional manipulation of droplets is still difficult. Here, we demonstrate the manipulation of droplets along arbitrary directions by using Z-shaped light patterns that rotate the electric field by an arbitrary angle. We provide a theoretical model for driving droplets in different directions. It is verified by Comsol simulations and experiments. Optimization of the width of the notches provides quite large increase of the driving voltage in the y-direction. The chip can move dyed water droplets in the y-direction at a maximum speed of 4.86 mm/s. Such multidimensional droplet driving opens new possibilities for single-sided continuous optoelectrowetting such as merging droplets that are not in line, efficient droplet mixing, and bypassing droplets to avoid coalescence.

Two-dimensional acoustic manipulation in air using interference of standing wave field by three sound waves

A number of small ultrasonic transducers were placed on a flat surface to form a directional ultrasonic sound source. A standing wave field with a hexagonal distribution of sound pressure like a honeycomb was formed when ultrasonic waves were superimposed from three directions using three of these sources. Small objects could be trapped at the nodes of the sound pressure in the sound field. When the phase of the three sources was changed, the sound pressure distribution shifted in the direction of the sound axis of the sources, and the objects trapped at the pressure nodes also shifted. For more stable object trapping, the ultrasonic transducers were placed on the inner wall of a semicylinder and the ultrasonic waves were focused to form a thin two-dimensional planar standing wave field. Three of these sources were used in the experiment, and it was possible to manipulate the objects more stably.

In vivo acoustic manipulation of microparticles in zebrafish embryos.

In vivo micromanipulation using ultrasound is an exciting technology with promises for cancer research, brain research, vasculature biology, diseases, and treatment development. In the present work, we demonstrate in vivo manipulation of gas-filled microparticles using zebrafish embryos as a vertebrate model system. Micromanipulation methods often are conducted in vitro, and they do not fully reflect the complex environment associated in vivo. Four piezoelectric actuators were positioned orthogonally to each other around an off-centered fluidic channel that allowed for two-dimensional manipulation of intravenously injected microbubbles. Selective manipulation of microbubbles inside a blood vessel with micrometer precision was achieved without interfering with circulating blood cells. Last, we studied the viability of zebrafish embryos subjected to the acoustic field. This successful high-precision, in vivo acoustic manipulation of intravenously injected microbubbles offers potentially promising therapeutic options.

Spatiotemporal manipulation of three-dimensional vectorlight fields

<p indent=0mm>Vector light fields show many exotic phenomena and applications that do not exist in scalar light fields, but current research of polarization optics mainly focuses on two-dimensional polarization manipulation. Recently, researchers have proposed a novel spatiotemporal manipulation method of synthetic vector light fields based on metasurfaces with asymmetric photonic spin-orbit interactions, which can in principle produce arbitrary three-dimensional vector light fields. This method expands polarization optics from two-dimensional space to three-dimensional space, provides some new ideas for the research of vector light field manipulation and its property in long-distance energy and information transmission, and has application prospects in the fields of focal field manipulation, light force control, laser communication, laser processing, etc.

Addendum: Multiaxial resonant MEMS force sensor (2018 J. Micromech. Microeng. 28 105002)

In this letter we present an MEMS Sensor to measure displacement in at least two directions. The sensor device is a resonant, Lorentz force driven and cross-shaped sensing structure whereas the measurement signal equals the change of the resonance frequency induced by the deformation of the sensor-frame. This device is a pre-study to implement the sensor in a two-dimensional micro manipulation system for which the team uses a micro system analyzer to detect the resonance frequencies of the different vibration modes. The sensor-frame deformation between 0.1 and 2 µm is generated by four piezo actuators. With this setup, the sensor achieves a sensitivity of up to 20 nm Hz−1. The device is fabricated from a 100 mm SOI wafer with standard CMOS processes and has two Pt1000 elements integrated on the device layer to compensate any effects caused by thermal extension of the structure or temperature induced changes of material parameters.

A Two-Dimensional Manipulation Method for a Magnetic Microrobot with a Large Region of Interest Using a Triad of Electromagnetic Coils.

This paper proposes an effective method to manipulate the 2D motions of a magnetic small-scale robot (microrobot) within a relatively large working area using a triad of electromagnetic coils (TEC). The TEC is a combination of three identical circular coils placed at the vertices of an equilateral triangle. Since it is geometrically compact and requires only three control variables (input currents), the TEC can be effectively used to generate various magnetic fields that can be used to maneuver various functional microrobots. In this paper, we established several equations to calculate the input currents of the TEC required to move a microrobot along a designated pathway effectively and precisely. We also constructed an experimental setup to demonstrate and validate the controlled motions of the microrobot using the proposed method. The results showed that the proposed method can effectively improve the TEC’s practical working area (region of interest) for manipulating the microrobot, which can possibly be applied to biomedical and biological applications, including minimally invasive surgery, targeted drug and cargo delivery, microfluidic control, etc.

Spoon-like Beams Generated with Exponential Phases

In this paper, we report a new kind of beam, named “spoon-like” beams, generated with the exponential phase. The intensity distributions and transverse energy flow of the spoon-like beam at the focal plane are analyzed theoretically and experimentally. The results demonstrate that the size of the spoon-like beam becomes enlarged with the increasing power exponent n, and the length of the spoon-like intensity trajectory becomes shorter with the increasing parameter p. Furthermore, there is an intensity gradient along the spoon-like trajectory of the beam, which introduces the intensity-gradient force exerted onto microparticles. The experiment on optical tweezers demonstrates that the focused beams can create spoon-like traps for the two-dimensional manipulation of particles.

Two-Dimensional Manipulation of Droplets on a Single-Sided Continuous Optoelectrowetting Digital Microfluidic Chip

Two-Dimensional Manipulation of Droplets on a Single-Sided Continuous Optoelectrowetting Digital Microfluidic Chip

Precise position and angular control of optical trapping and manipulation via a single vortex-pair beam

Optical trapping and manipulation using structured laser beams now attract increasing attention in many areas including biology, atomic science, and nanofabrication. Here we propose and demonstrate experimentally the use of a single vortex-pair beam in two-dimensional optical trapping and manipulation. Using the focal properties of such vortex-pair beams, we successfully manipulate two spherical microparticles simultaneously, and obtain the precise position-control on the microparticles by adjusting the off-axis parameter a of the vortex-pair beam. Furthermore, we also realize the high-precision angular-controllable rotation of cylindrical microrods by rotating the initial phase structure of such vortex-pair beams, which is like an optical wrench due to two focused bright spots at the focal plane of objective lens. Our experimental result provides an alternative manipulation of microparticles and may have potential applications in biological area, and optically driven micromachines or motors.

Three-Dimensional Trapping and Dynamic Axial Manipulation with Frequency-Tuned Spiraling Acoustical Tweezers: A Theoretical Study

Holographic acoustical tweezers based on Archimedes-Fermat spiraling interdigitated transducers (SIDTs) are a versatile tool for the selective manipulation of microparticles [Baudoin et al., Sci. Adv. 5, eaav1967 (2019)] and cells [Baudoin et al., Nat. Commun., 11, 4244 (2020)] in a standard microfluidic environment. These binary active holograms produce some focused helical wave, with the ability to trap particles at the vortex core. Yet, all the studies conducted with SIDTs have so far been restricted to two-dimensional (2D) manipulation only. Here we show through a theoretical study that (i) a 3D radiation trap for microparticles and cells can be obtained with spiraling tweezers with sufficiently large aperture and that (ii) the particles can be displaced axially by simply tuning the driving frequency, without any motion of the transducer. This work opens perspectives for 3D cells and microparticles manipulation with single-beam acoustical tweezers.

Controlled Manipulation and Active Sorting of Particles Inside Microfluidic Chips Using Bulk Acoustic Waves and Machine Learning.

Manipulation of cells, droplets, and particles via ultrasound within microfluidic chips is a rapidly growing field, with applications in cell and particle sorting, blood fractionation, droplet transport, and enrichment of rare or cancerous cells, among others. However, current methods with a single ultrasonic transducer offer limited control of the position of single particles. In this paper, we demonstrate closed-loop two-dimensional manipulation of particles inside closed-channel microfluidic chips, by controlling the frequency of a single ultrasound transducer, based on machine-vision-measured positions of the particles. For the control task, we propose using algorithms derived from the family of multi-armed bandit algorithms. We show that these algorithms can achieve controlled manipulation with no prior information on the acoustic field shapes. The method learns as it goes: there is no need to restart the experiment at any point. Starting with no knowledge of the field shapes, the algorithms can (eventually) move a particle from one position inside the chamber to another. This makes the method very robust to changes in chip and particle properties. We demonstrate that the method can be used to manipulate a single particle, three particles simultaneously, and also a single particle in the presence of a bubble in the chip. Finally, we demonstrate the practical applications of this method in active sorting of particles, by guiding each particle to exit the chip through one of three different outlets at will. Because the method requires no model or calibration, the work paves the way toward the acoustic manipulation of microparticles inside unstructured environments.