Asymmetric Beam Research Articles

88‐3: Fast Selective Laser‐Induced Etching and Asymmetric 3D Hologram Laser Beam for Narrow Bezel Thin Display †

Here we demonstrate fast selective laser‐induced etching (SLE) process with three‐dimensional (3D) hologram optics to reduce display bezel thickness with cost effective methods. To apply fast SLE for display manufacturing, one‐side etching process should be presumed to protect display active area. We developed one‐side selective laser‐induced etching with asymmetric 3D hologram laser beam satisfying with commercial mechanical strength. Faster etch process having etch rate 10 µm/min than common SLE, 1~3 µm/min was developed. Furthermore, we achieve that bezel thickness is 100 µm shorter than wheel scribing and CNC grinding.

Vibration response of ultra-shallow floor beam (USFB) composite floors

This paper examines the vibration response of the steel-concrete composite Ultra Shallow Floor Beam (USFB®) flooring system which incorporates asymmetric steel perforated beams to accommodate the concrete floor slab within the depth of the flanges while allowing reinforcement and/or service ducts to pass through the web openings. This is a lightweight flooring system that can accommodate long spans, thus becoming susceptible to floor vibrations due to external resonant dynamic loads. To investigate the influence of slab thickness and boundary conditions on the natural frequencies of the USFB flooring system, parametric studies are conducted using a finite element model and five floor spans. The model was first validated against an experimental test conducted by the authors. Emphasis is placed on the fundamental frequency to predict the possibility of resonance of this complex flooring system with typical human-induced dynamic loads in building structures. To further facilitate the practical numerical modelling and vibration analysis of buildings with USFB floors in standard commercial structural software, an analytical method of deriving equivalent isotropic plate properties is developed and its accuracy is numerically verified vis-à-vis with detailed ABAQUS models.

A Hybrid Tri-Stable Piezoelectric Energy Harvester with Asymmetric Potential Wells for Rotational Motion Energy Harvesting Enhancement

This paper proposes an asymmetric hybrid tri-stable piezoelectric energy harvester for rotational motion (RHTPEH). The device features an asymmetric tri-stable piezoelectric cantilever beam positioned at the edge of a rotating disk. This beam is uniquely configured with an asymmetric arrangement of magnets. Additionally, an elastic amplifier composed of a vertical and a rotating spring connects the beam’s fixed end and the disk. This setup enhances both the rotational amplitude and vertical displacement of the beam during motion. A comprehensive dynamical model of the RHTPEH was developed using Lagrange’s equations. This model facilitated an in-depth analysis of the system’s behavior under various conditions, focusing on the influence of key parameters such as the asymmetry in the potential well, the stiffness ratio of the amplifier springs, the radius of the disk, and the disk’s rotational speed on the nonlinear dynamic response of the system. The results show that the asymmetric hybrid tri-stable piezoelectric energy harvester makes it easier to harvest the vibration energy in rotational motion and has excellent power output performance compared with the symmetric tri-stable piezoelectric energy harvester. The output power magnitude of the system at higher rotational speeds increases as the radius of rotation expands, but when the rotational speed is low, the steady-state output power magnitude of the system is not sensitive to changes in the radius of rotation. Theoretical analysis and numerical simulations validate the effectiveness of the proposed asymmetric RHTPEH for energy harvesting in low-frequency rotating environments.

Design and Application of Liquid Silicone Rubber Light Guide in Compact Automotive Headlamps

Traditional car headlights use halogen or high-intensity discharge (HID) lamps paired with a reflector cup, fisheye lens, and shading plate to comply with ECE112B (Headlamps with an Asymmetrical Passing Beam) regulations. This design has issues such as large and bulky volumes, and it sacrifices optical efficiency due to the shading plate. This paper proposes a solution using an LED light source coupled with a Liquid Silicone Rubber-Light Guide (LSR-LG) for compact automotive low-beam headlights. By employing the principle of total internal reflection, the light beam is confined within the LSR-LG to reduce the volume of the car lamp. Simultaneously, optimized the structure and adjusted the light distribution. In the prototype measurements, the LED combined with the LSR-LG in the compact automotive headlamps module exhibited light intensities of 11,942 cd, 12,898 cd, and 298.2 cd at measurement points 75 R, 50 R, and BR, respectively, by ECE R112B standards. Simultaneously, the design effectively reduced the car lamp module’s volume to 90.63 mm × 164.53 mm × 73.37 mm. This design offers advantages such as energy efficiency, lightweight construction, and compact size. It also complies with ECE R112B regulations, showing promising potential as an excellent choice for the next generation of automotive low-beam headlights.

Beam monitor chamber calibration of a synchro-cyclotron high dose rate per pulse pulsed scanned proton beam

Objective. Ionization chambers, mostly used for beam calibration and for reference dosimetry, can show high recombination effects in pulsed high dose rate proton beams. The aims of this paper are: first, to characterize the linearity response of newly designed asymmetrical beam monitor chambers (ABMC) in a 100–226 MeV pulsed high dose rate per pulse scanned proton beam; and secondly, to calibrate the ABMC with a PPC05 (IBA Dosimetry) plane parallel ionization chamber and compare to calibration with a home-made Faraday cup (FC). Approach. The ABMC response linearity was evaluated with both the FC and a PTW 60019 microDiamond detector. Regarding ionometry-based ABMC calibration, recombination factors were evaluated theoretically, then numerically, and finally experimentally measured in water for a plane parallel ionization chamber PPC05 (IBA Dosimetry) through k s saturation curves. Finally, ABMC calibration was also achieved with FC and compared to the ionometry method for 7 energies. Main results. Linearity measurements showed that recombination losses in the new ABMC design were well taken into account for the whole range of the machine dose rates. The two-voltage-method was not suitable for recombination correction, but Jaffé’s plots analysis was needed, emphasizing the current IAEA TRS-398 reference protocol limitations. Concerning ABMC calibration, FC based absorbed dose estimation and PPC05-based absorbed dose estimation differ by less than 6.3% for the investigated energies. Significance. So far, no update on reference dosimetry protocols is available to estimate the absorbed dose in ionization chambers for clinical high dose rate per pulse pulsed scanned proton beams. This work proposes a validation of the new ABMC design, a method to take into account the recombination effect for ionometry-based ABMC calibration and a comparison with FC dose estimation in this type of proton beams.

Vibration Characteristics of Asymmetric Flexible Cantilever Beams Connected to a Central Rigid Body

A satellite with two solar wings can be modeled using a pair of symmetric flexible cantilever beams connected to a central rigid body. Due to certain reasons, the symmetric flexible cantilever beams may be turned into asymmetric ones, which will inevitably influence the vibration properties of the structural system. By changing the structural sizes and adding local mass on one side of the two beams, a structural system with asymmetric mass distribution is obtained and its vibration characteristics are investigated. Hamilton’s principle with the assumed mode method is employed to establish the equation of motion of the asymmetric structural system. The natural frequencies, mode shapes, frequency response curves and displacement time histories of the system are calculated, and they are compared with those of the structural system with a symmetric mass distribution. The correctness and feasibility of the present analytical method are verified by means of the finite element method (FEM) and a vibration experiment. The analytical results show that the mass asymmetry of the two beams leads to the mode localization phenomenon, and the coupling effect between the two beams and the central rigid body is enhanced. The larger the mass asymmetry is and the closer the position of the added local mass to the end of the cantilever beam is, the more obvious of the mode localization phenomenon is and the more obvious of the coupling effect between the two beams and the central rigid body is. The present investigation results are helpful for the dynamic analysis and design of spacecraft structures composed of flexible solar wings and a central rigid body.

Commissioning of a gantry beamline with rotator at a synchrotron-based ion therapy center

This paper provides an overview of the worldwide first commissioning of a gantry beamline with a rotator at the MedAustron synchrotron-based proton/ion cancer therapy facility in Wiener Neustadt, Austria. The gantry beamline consists of the high energy beam transfer (HEBT) line and the gantry beam transport system. It transports the beam from the synchrotron to the gantry-room isocenter. The HEBT transports the beam from the synchrotron to the gantry entrance, which is the coupling point between the HEBT and the gantry. The rotator is one of the HEBT modules, thus it is an integral part of the gantry beamline. The MedAustron rotator is the worldwide first rotator system used to match slowly extracted asymmetric beams from the synchrotron to the rotating gantry. In this paper, main attention is paid to ion-optical and beam-alignment aspects of the beamline commissioning. A novel orbit-correction and beam-alignment technique has been developed specifically for the beamline with the rotator. While the theoretical concept of the rotator has existed for almost two decades, the MedAustron rotator is the first hardware implementation of this concept all over the world. The presented overview of the beamline commissioning includes a description of the principal technical solutions and main results of the first beam-transport measurements. Since the measured beam size and beam position agree well with theoretical predictions, one can conclude that the proof-of-concept of the rotator-matching has been successfully accomplished. Published by the American Physical Society 2024

Bending-bending-torsion coupled wave propagation in thin-walled asymmetric metabeam: An analytical and experimental analysis

The primary focus of this paper is to analyze the impact of the periodic resonators on the wave dispersion phenomenon of a thin-walled asymmetric beam. An analytical framework has been developed to study the triply coupled flexural and torsional wave propagation in an asymmetric metabeam. The resonators are modeled as a beam with a lumped mass at the center and placed eccentrically from the shear center. Their periodicity allows them to generate a subwavelength attenuation band in the beam. The governing equations for the coupled bending-bending-torsion vibration of a metabeam having an asymmetric cross-section are considered for generating the dispersion phenomenon, including the warping effect. Applying the Bloch-Floquet principle, the dispersive characteristics of the asymmetric metabeam are obtained by using the transfer matrix method. The modal characteristics of an asymmetric beam without a resonator are computed using the spectral element method and are validated with previously published results. Subsequently, the attenuation band is investigated due to the presence of a resonator and followed by the transmittance spectrum to verify the suppression of the elastic waves in the attenuation band. The experimental analysis is carried out to validate the analytical framework by obtaining the modal frequencies from the frequency response function. The detailed parametric investigation reveals that the resonator’s position and characteristics significantly impact the occurrence of the band gap. A substantially wide attenuation band gap is attained by considering a continuous beam-mass resonator instead of a discrete spring-mass type resonator. This type of novel structure has the potential for the application of vibration control and acoustics.

Multilevel asymmetric coupler MAC polarization beam splitter for Si photonics technology

In this work, we present a new design of an integrated optical polarization beam splitter using the Multilevel Asymmetric Coupler MAC structure. The proposed structure is using CMOS compatible Si/SiO2 technology. The structure is tested using the Finite Difference Time Domain FDTD technique and showed a very good performance. The compromise between the structure footprint on Si and its performance is also investigated. The structure can offer an Extinction Ratio ER greater than 40 dB with a length of 5 µm. It can also be designed with a smaller length of only 2 µm but in this case its ER will be only 20 dB. It has a bandwidth of about 60 nm in which the insertion loss is less than 0.003 dB for the TE wave and less than 0.2 dB for the TM wave.

Three-dimensional flow velocity determination using laser-induced fluorescence method with asymmetric optical vortex beams

Laser-induced fluorescence (LIF) Doppler spectroscopy using an optical vortex beam with an asymmetric intensity distribution, referred to as aOVLIF, is proposed as a new method to measure plasma flow velocity. LIF spectra were calculated numerically using typical laboratory low-temperature plasma parameters, and it was revealed that an ion flow across the beam produces a frequency shift of the spectra. This method also has the capability of temperature measurements. The propagation effects of asymmetric optical vortex beams are discussed assuming an actual experiment, and it is found that the sensitivity to the transverse flow velocity is approximately unchanged. The aOVLIF method, which exploits the inhomogeneous phase structure of optical vortices, can be applied to the determination of three-dimensional velocity vectors and promises to enhance the usefulness of conventional LIF spectroscopy using plane waves.

Asymmetric toughening in the lap shear of metamaterial structural adhesives.

Metamaterial structural adhesives (MSAs), whose properties primarily rely on structural design, offer promising advantages over traditional adhesives, including asymmetric, switchable, and programmable adhesion. However, the effects of thick backing structures on the adhesion properties remain largely underexplored. Herein, we investigate a series of MSAs featuring a thin adhesive layer and an asymmetric thick beam structure terminated with a film. We conduct lap shear tests on the MSAs with varying terminated film thickness (t) and beam tilting angle (θ) while maintaining an identical adhesive layer. For MSAs with a thick terminated film (t = 2 mm), the effective adhesion energy is double that of solid samples without compromising shear strength, consistent with the theoretical predictions based on the crack trapping mechanism. Conversely, for MSAs with a thin terminated film (t = 0.5 mm), the maximum shear strength and effective adhesion energy are ∼2.8 times and ∼18.6 times those of solid samples, respectively, deviating significantly from the theoretical predictions due to new crack initiations. We further explore adhesion asymmetry by tuning the beam tilting angle (θ). For MSAs with highly tilted beams (θ = 70.3°), we achieve a maximum adhesion strength asymmetry factor of τ2/τ1 ∼ 2.2 for a thick terminated film (t = 2 mm), and a maximum adhesion energy asymmetry factor of Γ1/Γ2 ∼ 5.3 for a thin terminated film (t = 0.5 mm). Our work provides useful insights for designing metamaterial structural adhesives suitable for robotic grippers, wall-climbing robots, and wearable devices, particularly those requiring asymmetric, switchable, and stimuli-responsive adhesion, and adhesives on rough surfaces or in underwater conditions.

Janus bottlebrush compatibilizers.

Bottlebrush random copolymers (BRCPs), consisting of a random distribution of two homopolymer chains along a backbone, can segregate to the interface between two immiscible homopolymers. BRCPs undergo a reconfiguration, where each block segregates to one of the homopolymer phases, adopting a Janus-type structure, reducing the interfacial tension and promoting adhesion between the two homopolymers, thereby serving as a Janus bottlebrush copolymer (JBCP) compatibilizer. We synthesized a series of JBCPs by copolymerizing deuterated or hydrogenated polystyrene (DPS/PS) and poly(tert-butyl acrylate) (PtBA) macromonomers using ruthenium benzylidene-initiated ring-opening metathesis polymerization (ROMP). Subsequent acid-catalyzed hydrolysis converted the PtBA brushes to poly(acrylic acid) (PAA). The JBCPs were then placed at the interface between DPS/PS homopolymers and poly(2-vinyl pyridine) (P2VP) homopolymers, where the degree of polymerization of the backbone (NBB) and the grafting density (GD) of the JBCPs were varied. Neutron reflectivity (NR) was used to determine the interfacial width and segmental density distributions (including PS homopolymer, PS block, PAA block and P2VP homopolymer) across the polymer-polymer interface. Our findings indicate that the star-like JBCP with NBB = 6 produces the largest interfacial broadening. Increasing NBB to 100 (rod-like shape) and 250 (worm-like shape) reduced the interfacial broadening due to a decrease in the interactions between blocks and homopolymers by stretching of blocks. Decreasing the GD from 100% to 80% at NBB = 100 caused an increase the interfacial width, yet further decreasing the GD to 50% and 20% reduced the interfacial width, as 80% of GD may efficiently increase the flexibility of blocks and promote interactions between homopolymers, while maintaining relatively high number of blocks attached to one molecule. The interfacial conformation of JBCPs was further translated into compatibilization efficiency. Thin film morphology studies showed that only the lower NBB values (NBB = 6 and NBB = 24) and the 80% GD of NBB = 100 had bicontinuous morphologies, due to a sufficient binding energy that arrested phase separation, supported by mechanical testing using asymmetric double cantilever beam (ADCB) tests. These provide fundamental insights into the assembly behavior of JBCPs compatibilizers at homopolymer interfaces, opening strategies for the design of new BCP compatibilizers.

Acoustic Bilayer Gradient Metasurfaces for Perfect and Asymmetric Beam Splitting

We experimentally and theoretically present a paradigm for the accurate bilayer design of gradient metasurfaces for wave beam manipulation, producing an extremely asymmetric splitting effect by simply tailoring the interlayer size. This concept arises from anomalous diffraction in phase gradient metasurfaces and the precise combination of the phase gradient in bilayer metasurfaces. Ensured by different diffraction routes in momentum space for incident beams from opposite directions, extremely asymmetric acoustic beam splitting can be generated in a robust way, as demonstrated in experiments through a designed bilayer system. Our work provides a novel approach and feasible platform for designing tunable devices to control wave propagation.

Asymmetric vortex beam emission from a metasurface-integrated microring with broken conjugate symmetry

Vortex beams that carry orbital angular moment (OAM) have recently attracted a great amount of research interest, and metasurfaces and planar microcavities have emerged as two prominent, but mostly separated, methods for Si chip-based vortex beam emission. In this work, we demonstrate in numerical simulation for the first time the hybridization of these two existing methods in a Si chip-based passive emitter (i.e., a light coupler). A unique feature of this device is its broken conjugate symmetry, which originates from introducing a metasurface phase gradient along a microring. The broken conjugate symmetry creates a new phenomenon that we refer to as asymmetric vortex beam emission. It allows two opposite input directions to generate two independent sets of OAM values, a capability that has never been reported before in Si chip-based passive emitters. In addition, we have also developed here a new analytical method to extract the OAM spectrum from a vector vortex beam. This analytical method will prove to be useful for vector vortex beam analysis, as mode purity analysis has rarely been reported in literature due to the complexity of the full-vector nature of such beams. This study provides new approaches for both the design and the analysis of integrated vortex beam emission, which could be utilized in many applications such as free-space optical communications and microfluidic particle manipulation.

Flexible and Independent Control of Asymmetric Vortex Beams Based on Spin Multiplexing all Dielectric Metasurface

Vortex beams carrying orbital angular momentum have important applications in optical communication, particle manipulation and quantum information. Vortex beams have multiplexed communication capabilities. Here, at the terahertz band, we propose a spin-multiplexed all-dielectric metasurface that combines vortex phase and encoding sequences. The metasurface can generate asymmetric vortex light with different topological charges under the condition of orthogonal circularly polarized light. Moreover, the flexible manipulation of the deflection angle of the vortex beam can be realized by changing the coding sequence. Meanwhile, the superposition of multifunctional coding sequences can also generate vortex beams with different states. Additionally, the focusing properties of the spin-multiplexed deflected vortex beam were analyzed. This work provides a new method for micro-nano integrated optics to generate deflected vortex light, which can be applied in data communication, micro-manipulation and other fields.

Stress-Strain State of an Asymmetrical Three-Layer Beam

Introduction. The three-layer structure, having a low weight, has sufficient rigidity and strength to absorb various force and physical impacts of both static and dynamic nature. By combining materials and thicknesses of bearing layers and filler, it is possible to achieve the desired physical and mechanical properties of the three-layer structure.In this regard, this paper considers the stress-strain state of a three-layer beam with different thicknesses of bearing layers and filler height.Materials and Methods. The calculation of a three-layer beam according to the known theory of calculation is presented. As an example, a three-layer beam with a length of 70 cm was considered, its width varied depending on the size of the hexagonal cell face of the filler. The thickness of the bearing layers was varied from 1 to 1.5 mm and the thickness of the filler from 0.12 to 0.30 mm. The bearing layers were made of aluminum AMG2-H, and the hexagonal honeycomb filler was made of aluminum alloy D16-AT.Results. Based on the obtained data, graphs of stresses and strains (deflections) variation with the distributed load were plotted for each tested specimen. The graphical dependences are given for symmetrical and asymmetrical three-layer beams.Discussion and Conclusion. The obtained theoretical data on deformations (deflections) and stresses made it possible to determine the effective combination of bearing layers, at which the three-layer beam becomes effective. On the basis of the analysis of these data, conclusions characterizing the efficiency improvement of the three-layer beam were made.

Stability analysis of a rotating asymmetric sandwich beam tapered along width and thickness subjected to pulsating axial load

The purpose of this research is to utilize computational method to study the stability of an asymmetric sandwich beam which has tapered-width as well as tapered-depth. The beam is also being subjected to rotary motion and axial load which is pulsating in nature. The governing equations of motionof the system is produced using the expanded Hamilton's notion, and also the boundary conditions are decided. The resultant equation of motion and associated boundary conditions are non-dimensionalized by using the extended Galerkin technique. To arrive at the Hill's equation for the analysis of static instability, the system of non-dimensionalized equations of motion must be solved. The parametric instability is determined by the Saito-Otomi criteria. The effect of various parameters such as taper parameters, shear parameter, rotational speed, hub radius, core-loss factor, and regions of parametric instability. Utilizing the necessary MATLAB algorithms, an investigation is conducted on a static bucking load and shown as a variety of graphs.

Asymmetry stagger array structure ultra-wideband vibration harvester integrating magnetically coupled nonlinear effects

Traditional energy harvesters often have limitations in terms of bandwidth and power output, resulting in poor performance. This study reports a multi-strategy ultra-wideband energy harvesting device that utilizes an asymmetry, stagger array, magnetic coupling, and nonlinearity strategies to achieve high power output over an ultra-wideband frequency range without the need for external power input. The energy harvesting device consists of a base, two elastic beams, and two sets of asymmetric palm-shaped piezoelectric cantilever beam structures, each with a magnet attached at the tip. By reasonably arranging the palm-shaped mechanism and magnets, a magnetic coupling effect is introduced to achieve high power density output at non-resonant frequencies. Numerical analysis is conducted to evaluate the performance of the proposed structure, assess the influence of structural parameters, and establish a dynamic model to analyze the energy harvesting device. Experimental results demonstrate that the structure achieves a maximum power output of 60.49 mW at 19.9 Hz and 0.5 g, with a peak power density of approximately 8.065 × 103 W/m3. Within an ultra-wideband frequency range that spans 6 Hz to 64.2 Hz, the energy harvester maintains an output voltage which is more than 5 V. Furthermore, temperature and humidity monitoring are performed using Bluetooth sensors to adaptively assess the energy harvesting device, eliminating the need for lithium batteries and ensuring stable signal transmission. The device can be utilized for condition monitoring in any unstable vibration environment, contributing to the realization of distributed monitoring in the Internet of Things (IoT).

Topological circular dichroism for asymmetric converging light beams

Light beams possess three types of angular momentum. They are the spin angular momentum, the extrinsic orbital angular momentum, and the intrinsic orbital angular momentum. Interaction of these momenta due to translational or cylindrical symmetry breaking leads to effects of the spin-orbit interaction of light, including topological effects. Topological optical activity or topological circular phase anisotropy, known as Rytov-Vladimirsky-Berry-Chao-Tomita plane polarization rotation, is the result of the extrinsic orbital angular momentum influence on the spin angular momentum. The effect manifests under linear polarized light propagation along a curved trajectory when the translational symmetry is breaking. We predict a new topological effect under the cylindrical symmetry breaking. This effect is the result of the extrinsic orbital angular momentum influence on the spin angular momentum in the converging asymmetrical light beam. It manifests as the transformation of linear polarized light into elliptically polarized one when an asymmetrical in the vertical direction beam passes through the left or right half of the focal plane. We have estimated the value of the ellipticity and proposed an experimental setup. We successfully observed the ellipticity change of 10(−3) using our method of small ellipticity determination. We have considered this transformation as the topological circular dichroism (topological circular amplitude anisotropy). We have demonstrated the connection of the ellipticity change with the value of the topological circular amplitude anisotropy R. The measured value of the topological circular amplitude anisotropy R turned out to be R=±(0.60±0.08)×10−3. This new effect of the spin-orbit interaction of light contributes to our understanding of the nature of light. It can be used to develop new sensors in optics, including nano and quantum optics.

Propagation of asymmetric optical vortex beams through turbulence and evolution of their OAM spectra

In the realm of wave propagation through turbulent media, the spectrum of the orbital angular momentum of optical vortex beams is known to undergo symmetric broadening. However, the evolution of beams that are initially azimuthally asymmetric represents a distinct phenomenon. In this work, we have developed an analytical model describing the propagation of asymmetric OAM beams through the so-called Kolmogorov turbulence. Our results describe how the perturbation strength and the initial beam properties lead to a nonsymmetric spectrum of OAM modes. These findings lay the groundwork for further use of asymmetric fields that propagate in inhomogeneous media and their applications such as communications and sensing.