Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session T23: Metamaterials: Mechanical and Optical |
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Sponsoring Units: DCMP Chair: Osama Bilal, University of Connecticut Room: Room 215 |
Thursday, March 9, 2023 11:30AM - 11:42AM |
T23.00001: Surface Area and Microstructure of Metallic Nanowire Foams James Malloy, Erin L Marlowe, Christopher J Jensen, Isaac Liu, Thomas Hulse, Gen Yin, Kai Liu The COVID-19 pandemic has shown the urgent need for the development of efficient, durable, reusable and recyclable face masks for the deep submicron size range. Nanowire-based low-density metal foams, synthesized by electrodeposition and sintering, have recently been shown to exhibit extremely large surface areas as well as outstanding filtration efficiencies (>96.6%) in the PM0.3 regime with breathability comparable to N-95 respirators [1]. Here we report the analysis of the microstructure of the foams, detailing how the growth parameters influence the overall surface area and characteristic feature size, as well as the influence of the microstructure on filtration efficiency. The foams have an overall low density, up to 30% of the bulk density. We have found that nanogranules deposited on the nanowires during electrodeposition greatly increase the surface area until the foam reaches about 13% bulk density, at which point the nanogranules begin to coalesce and surface area begins to decrease. Surprisingly, the overall surface area gained from the nanogranules has little correlation with an improvement in capture efficiency in the lowest density foams, and that the two parameters with the highest correlation are the nanowire density and diameter. These results demonstrate promising directions to optimize the foam microstructure for highly efficient submicron particulate filtration. |
Thursday, March 9, 2023 11:42AM - 11:54AM |
T23.00002: Transition Waves in Multistable Mechanical Metamaterials under Periodic Excitation Michael Bonthron, Eleonora Tubaldi Multistable mechanical metamaterials have recently provided unique platforms with wave guidance and wave steering capabilities. Arrays of symmetric/asymmetric bistable elements, such as elastically/plastically deformed arches, can be patterned to control the signal transmission and to passively achieve nonreciprocal wave propagation. In this work, sequential nonlinear transition wavefronts will be obtained by imposing an oscillatory transverse displacement to an element of a multistable metamaterial made of one-dimensional array of arches. Different excitation amplitude and frequencies will be considered and it will be showed how these features can be harnessed to control transition wavefronts propagation. In addition, the effect of multiple oscillatory inputs at different positions of the array will be investigated. The dynamics of the system will be theoretically studied by solving the continuum equations of motion with both direct time integration methods and numerical continuation techniques (i.e., pseudo-arclength continuation). Nonlinear wave interference, collision-like cases, and internal resonance phenomena will be characterized based on different oscillatory excitation parameters. This study will open avenues to the use of dynamic inputs to control sequential transition wavefronts in mechanical metamaterials |
Thursday, March 9, 2023 11:54AM - 12:06PM |
T23.00003: Auxetic metamaterials as a rich platform for controlling acoustic and elastic waves in a programmable manner Osama R Bilal In this work, we instigate the mechanics (both static and dynamic behavior) of a class of metamaterials with dynamically tunable properties. We consider three-dimensional basic building blocks (i.e., unit cells) with effective Poisson's ratios varying among positive, zero, and negative values. We analyze their effectiveness in controlling both elastic wave (vibrations) and airborne noise (sound) propagation in all-directions. Further, we investigate the effects of piezoelecticity to tune their band gap frequency ranges, even with the presence of various external mechanical loads. |
Thursday, March 9, 2023 12:06PM - 12:18PM |
T23.00004: Low-frequency and multiband elastic wave propagation in a 3D topological metamaterial Patrick Dorin, Mustafa Khan, Kon-Well Wang Elastic metamaterials that are engineered with topological phases contain waveguides that are protected from unwanted scattering in the presence of imperfections, enabling robust and omnidirectional control of elastic wave propagation. Recently, three-dimensional (3D) topological elastic metamaterials have been developed that support waveguides with planar and layer-selective transport behavior. These 3D topological elastic metamaterials operate in a singular frequency band that is often in the ultrasonic regime (>20 kHz). Thus, an unexplored opportunity exists to explore 3D topological elastic metamaterials that operate in multiple frequency bands in a low-frequency range (<20 kHz). To address this gap, this research proposes to advance the state of the art through the synthesis of a subwavelength 3D topological elastic metamaterial that harnesses multi-modal local resonance for multiband wave control. The novel 3D metamaterial is configured to obtain multiple low-frequency Dirac degeneracies by exploiting local resonance and the elastic analog of the quantum valley Hall effect. Theoretical and experimental findings reveal topological surface states with various polarizations in multiple low-frequency bands. The 3D metamaterial created in this study could serve as a macro-scale platform to explore novel multiband and subwavelength topological transport phenomena, while the research findings open a path to new frequency- and polarization-dependent wave control capabilities. |
Thursday, March 9, 2023 12:18PM - 12:30PM |
T23.00005: Metamaterial ring for omnidirectional shear-horizontal elastic waves: from working mechanism to experiment Hong Jae Kim, Chung Il Park, Kiyean Kim, Yoon Young Kim High transduction efficiency is essential in developing any transducer. This efficiency issue becomes more critical with omnidirectional waves, such as omnidirectional SH (shear-horizontal) waves in a plate, because the generated power decreases as an inverse square function of the radial coordinate. To substantially enhance the efficiency, we propose a metamaterial ring ('meta-ring') that can be attached to a target plate without directly modifying the transducer. We establish a rigorous theory to explain the transduction efficiency boosting mechanism for an omnidirectional SH wave that typical ultrasonic transducers can generate. Our meta-ring concepts are based on adjusting the effective characteristic impedance of the plate carrying the wave and an elaborate utilization of the Fabry-Perrot resonance. We use an equivalent mass-spring model for the theoretical analysis and employ the effective medium concept. The transduction efficiency enhancement by the proposed meta-ring, as confirmed by wave experiments performed in an aluminum plate, was over 250%. The proposed meta-ring method does not require any active element, only requiring external attachment of a T-shaped ring element. Therefore, it can be a new way to enhance the transducer in various applications for non-destructive testing, supported by a theoretical foundation. |
Thursday, March 9, 2023 12:30PM - 12:42PM |
T23.00006: Measuring Band Structures in Acoustic Metamaterials Via Multiplexed Microphones Bradley K Baltz, Benjamin H November, Jenny E Hoffman, Nicole Zhao Twisted van der Waals heterostructures have emerged as tunable systems for studying correlated electrons. However, the process of exploring this vast phase space offor quantum materials is laborious and expensive. Acoustic metamaterials can be used to mimic the behaviors of these quantum materials, serving as cheap and rapid prototypes for vdW heterostructures. Twisted bilayer graphene is one such system that has already been successfully translated to an acoustic metamaterial, made up of air cavities in a steel matrix [1]. As acoustic metamaterials become larger and more complex to mimic, with smaller twist angles and larger moire unit cells, it is useful to be able to measure multiple lattice sites simultaneously in order to analyze the band structure of the quantum material analog. We have developed a multiplexed microphone circuit that greatly increases the efficiency of band structure measurements, and we have applied it to the acoustic metamaterial analog of graphene. |
Thursday, March 9, 2023 12:42PM - 12:54PM |
T23.00007: Novel Anisotropic Metamaterials for Manipulating Multi-Modal Elastic Waves at Oblique Incidence Jeseung Lee, Yoon Young Kim The manipulation of elastic waves, such as perfect transmission across dissimilar media, is challenging not just because of impedance mismatch but also because of the existence of multiple elastic wave modes, longitudinal and transverse. Thereby, elastic wave manipulation requires elaborate simultaneous control of longitudinal and transverse waves having different impedances and phase velocities. The situation becomes more complicated when an elastic wave is obliquely incident at an interface because the oblique incidence always couples longitudinal and transverse waves. The constitutive relation that requires a fourth-order elasticity tensor also complicates the analysis of elastic waves. On the other hand, the higher-order tensor offers more freedom to 'design' the constitutive relation. Among others, we focus on a wide range of anisotropy of the elasticity tensor and propose to utilize the anisotropy of an elastic medium as much as possible to find novel anisotropic metamaterials for the desired wave manipulation. After presenting the derived conditions of anisotropy for some wave manipulation problems, we present an example of perfect retroreflection of an elastic wave using anisotropic metamaterials and experimental results performed with the realized metamaterials that are made on an aluminum plate with elaborate void drilling. The practical significance of the designed anisotropic metamaterials is also demonstrated. |
Thursday, March 9, 2023 12:54PM - 1:06PM |
T23.00008: Triggering of transition waves by the collision of solitons or breathers in bistable mechanical metamaterials Vincent Tournat, Apostolos Paliovaios, Vassos Achilleos, Georgios Theocharis, Hiromi Yasuda, Hang Shu, Weijian Jiao, Jordan R Raney, Katia Bertoldi It has recently been shown that flexible mechanical metamaterials support a wide range of nonlinear waves, including solitons or breathers. Interestingly, these systems can also be designed to be multistable, thereby enabling them to further support transition waves. In this talk, we analyze the interaction and collision of several types of propagating nonlinear waves in such bistable metamaterials, ultimately leading to the triggering of transition waves (kinks or topological solitons). We analyze in particular the necessary conditions, amplitude, phase of nonlinear waves brought to collision, to trigger transition waves, as well as the influence of localized defects. The numerical simulations and analytical results are completed by experimental demonstrations for several specific cases. Such processes have potentially exciting implications, since they allow the reconfiguration of a metamaterial from one stable state to another, at a distance, and starting from a desired position in the medium. Furthermore, flexible mechanical metamaterials represent a rich platform to test or apply developed models based on bistable nonlinearity and extend our fundamental knowledge on nonlinear wave dynamics. |
Thursday, March 9, 2023 1:06PM - 1:18PM |
T23.00009: Nonlinear Constitutive Law Optimization for Wave Tailoring in Architected Materials Brianna MacNider, Nicholas Boechler, H. Alicia Kim Nonlinearity is at the forefront of research that seeks to achieve novel wave properties in architected systems. Microstructural elements which display nonlinear constitutive laws have been extensively explored in the context of novel applications in acoustic metamaterials, impact mitigation, and energy trapping materials. To date, however, much experimental exploration of this space has been discrete and opportunistic, due to the difficulty of realizing desired constitutive laws in real-world structures. Topology optimization is a powerful tool to address such an inverse design problem, but has been underutilized in this space due to the high nonlinearity of the design space and the presence of many local optima. |
Thursday, March 9, 2023 1:18PM - 1:30PM |
T23.00010: Phase Transition driven Electromechanically Reconfigurable 3D THz Metadevice Saurav Prakash, Prakash Pitchappa, Ariando Ariando, Ranjan Singh, Thirumalai V Venkatesan Terahertz (THz) electromagnetic radiation has numerous promising applications including 6G wireless communication, fingerprint chemical sensing, security screening, and centimeter-level object localization. However, the lack of efficient devices to generate, manipulate, and detect THz waves has remained a key technological challenge. Electrically reconfigurable metasurfaces with 3D resonators would allow for new paradigms of light-matter interaction inaccessible through their 2D counterparts. In this work, we demonstrate a robust platform to realize THz metadevices with colossal structural reconfiguration between planar and 3D geometries powered by the phase transition in VO2. We combine two counteracting driving forces for the actuation of the resonators – (i) inhomogeneous stress-induced folding, which is non-volatile, and (ii) strain associated with the insulator-to-metal transition in VO2, which is volatile. This massive structural reconfiguration allows for advanced THz manipulation capabilities, while the electrical stimulus ensures high compactness and integrability. THz metadevices with 3D reconfigurable split ring resonators have been fabricated and characterized to illustrate the proposed platform. Beyond the functionalities enabled by the massive structural reconfiguration of THz resonators, the unique material properties of VO2 such as the hysteretic nature of the phase transition of VO2, is also harnessed to demonstrate multi-state memory effect using transient sub-threshold current stimulus. Hence, these novel VO2 MEMS metasurfaces are functionally versatile, spectrally scalable, and electrically controlled and hence are highly attractive for the realization of 6G communication devices such as reconfigurable intelligent systems, holographic beam formers, and spatial light modulators. |
Thursday, March 9, 2023 1:30PM - 1:42PM |
T23.00011: Quantum control of vortex beams using metasurfaces Jensen Li, Hong Liang, Hammad Ahmed, Xianzhong Chen Metasurfaces are very useful to control and hybridize different degrees of freedom of light on a single interface composed of nanostructures, heading to many applications including multi-functional lenses, light-field imaging and holograms in classical optics. More recently, tremendous efforts have been made on pushing the operations of metasurfaces to the quantum optical regime. Here, we provide and experimentally demonstrate a scheme to remotely control the vortex beam structure using polarization-entangled photon pairs together with a metasurface. By adopting a heralding technique, the spin-orbit coupling provided by the metasurface directly translates to a tailor-made entanglement of the orbital angular momentum with the polarization degree of freedom in the signal arm. Then, the polarization of the heralding photon at the other end is used to remotely control the vortex structure of the signal photon, directly manifested as an orbital rotation. We further demonstrate that such heralding control can be continuous, going beyond the conventional switching applications using heralding photons. The investigations point to a versatile metasurface platform for quantum communication and information processing. |
Thursday, March 9, 2023 1:42PM - 1:54PM |
T23.00012: Non-Vanishing Optical Helicity in Thermal Radiation with Symmetry-Broken Metasurfaces Xueji Wang, Tyler Sentz, Sathwik Bharadwaj, Subir Ray, Yifan Wang, Dan Jiao, Limei Qi, Zubin Jacob Thermal radiation describes the universal phenomenon that all objects at non-zero temperatures emit infrared electromagnetic energy. Significant research progress has been made so far in tailoring its temporal coherence and spatial coherence. However, the photon spin, another crucial characteristic of electromagnetic radiation, is commonly ignored, since most thermal emitters show weak to zero spin angular momentum (SAM) in the emitted waves. Surprisingly, the thermal radiation reaching the earth from many astronomical objects possesses significant circular polarization. The unique phenomenon provides strong evidence for the presence of a magnetic field around stars or reveals the existence of chiral organic molecules. Therefore, revealing photon spin characteristics in thermal radiation is of fundamental interest as it contains unique information regarding the emitters. Here, we demonstrate spinning thermal radiation with a non-vanishing optical helicity via symmetry-broken metasurfaces. We design non-vanishing optical helicity by engineering a dispersionless band that emits omnidirectional spinning thermal radiation, where our design reaches 39% of the fundamental limit. Our results firmly suggest metasurfaces can impart spin coherence in the incoherent radiation excited by thermal fluctuations. The symmetry-based design strategy also provides a general pathway for comprehensively controlling thermal radiation in its temporal, spatial, and spin coherence. |
Thursday, March 9, 2023 1:54PM - 2:06PM |
T23.00013: Mimicking quantum tunneling using active mechanical circuits Lea Sirota, Sayan Jana The striking analogy between the electronic band structure of solids and the frequency dispersion of classical systems inspired the idea of mimicking quantum effects on classical platforms. For example, a great deal of attention was devoted to mimicking quantum topological phenomena, exploiting the band structure properties to achieve unique functionalities such as beam-like narrow waves, which are immune to backscattering from corners, bents, and structural defects. However, an entire class of quantum phenomena related to tunneling remains significantly under-explored for classical waveguiding. This includes Klein tunneling of relativistic particles through potential barriers of arbitrary heights and widths, tunneling of particles across the event horizon of black holes, tunneling of electron pairs through superconducting junctions, and more. The common property of these effects is an unusual and counterintuitive ability of particles to cross gaps, barriers or interfaces, despite this crossing being seemingly forbidden by energy considerations. Here we derive a classical mechanical analogue of two such effects, tunneling through the event horizon and tunneling of non-Hermitian skin modes, which turn out to require structural couplings that violate the rules of classical dynamics. We show how these effects can be precisely realized using active mechanical circuits, which operate in a real-time-controlled closed loop. |
Thursday, March 9, 2023 2:06PM - 2:18PM |
T23.00014: Prediction of Effective Optical Properties of Stratified Medium Beyond the Quasistatic Limit Jaeuk Kim, Salvatore Torquato Most of the previous approximations to predict the effective dielectric constant of composites apply to the quasistatic (long-wavelength) regime. Recently, Torquato and Kim [PRX 11, 021002 (2021)] derived exact nonlocal formulas for the effective dynamic dielectric constant tensor for general two-phase microstructures using the "strong-contrast" expansion formalism that is applicable down to intermediate wavelengths. In the previous work, however, accurate approximation formulas were obtained for isotropic media. Here we extract the corresponding formula for stratified microstructures in three dimensions. Similar to the previous approximations, this approximation is a rational function that depends on certain integrals involving the two-point correlation function or its Fourier counterpart (i.e., spectral density), and hence, accounts for the multiple scattering to all orders. We apply our new formulas to a variety of hyperuniform and nonhyperuniform disordered stratified media. Our theoretical results compare favorably to full-waveform simulations. We show that light in hyperuniform systems, particularly stealthy hyperuniform ones, experiences exceptionally lower loss than their nonhyperuniform counterparts. |
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