Article
Physics, Multidisciplinary
Mahdiyeh Ghoreshi, Ali Bahrami
Summary: This paper designs a cloak using the self-collimation property and existence of band gap in two-dimensional phononic crystals to change the direction of waves and prevent collision with an object. The structure's performance is independent of the shape of the hidden object, making it suitable for sound insulation. Calculations of reflected waves' pressure, waves reaching the invisibility area, and waves reaching the back of the object demonstrate the cloak's invisibility. Sound waves within the invisibility area cannot be detected by detectors.
Article
Physics, Condensed Matter
Mahdiyeh Ghoreshi, Ali Bahrami
Summary: This paper introduces a cloaking structure based on two-dimensional phononic crystals, which has the ability to hide objects of any size and shape. By changing the dimensions of the unit cell and filling factor, the operating frequency can be easily adjusted. The structure utilizes the negative refraction and self-collimation properties of phononic crystals, effectively reducing scattering and shadow effects.
SOLID STATE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Yaoxian Zheng, Qiong Wang, Mi Lin, Zhengbiao Ouyang
Summary: This study numerically investigates light propagation in photonic crystal membranes containing hyperbolic metamaterials. The results show that hyperbolic metamaterials can improve tunability and self-collimation effect of photonic crystals. The study also demonstrates the efficient control of beam behaviors using hyperbolic metamaterial photonic crystal membranes.
Article
Chemistry, Physical
Mikhail Marunin, Nataliya Polikarpova
Summary: This paper presents a study of the propagation of elastic waves in two-dimensional phononic crystals based on fused silica. The band structures and acoustic characteristics of the phononic crystals are analyzed, and it is shown that the choice of the crystal's geometry can control the distribution of inverse phase velocities and energy walk-off angles. Three mutually orthogonal acoustic modes are observed in the phononic crystal, regardless of the direction of the acoustic wave's propagation.
Article
Chemistry, Multidisciplinary
Feng Gao, Sarah Benchabane, Amine Bermak, Shurong Dong, Abdelkrim Khelif
Summary: This article reports a micron-scale phononic waveguide constructed by line defects in PnCs, which enables on-chip, tightly confined guiding, bending, and splitting of surface acoustic waves (SAWs). The proposed phononic waveguides demonstrate the feasibility of precise local manipulation of SAW that is essential for emerging frontier applications, notably for phonon-based classical and quantum information processing.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Crystallography
Xinsa Zhao, Guodong Hao, Yu Shang, Jianning Han
Summary: Conventional acoustic systems have difficulty in sensing weak acoustic fault signals in complex mechanical vibration environments. To address this issue, a three-dimensional device, coupling gradient acoustic metamaterials (GAM) with phononic crystals (GAM-PC), is proposed in this paper. The strong wave compression effect coupled with the phononic crystal equivalent medium mechanism is utilized to enhance the perception of weak acoustic signals at the target frequency. Numerical simulations and experiments verify the superior amplification capability of the GAM-PC structure for loud signal amplitudes. Additionally, the GAM-PC structure has a narrower bandwidth per slit, making it more frequency selective, and it can separate different frequency components. This work is expected to be applied in signal monitoring in environments with strong noise.
Article
Nanoscience & Nanotechnology
Samuli Heiskanen, Tuomas A. Puurtinen, Ilari J. Maasilta
Summary: Controlling thermal transport at the nanoscale is crucial for various applications. This study demonstrates that thermal conductance can be controlled using three-dimensional phononic crystals, without the need for suspension. Experimental results show that at sub-Kelvin temperatures, these structures can enhance thermal conductivity.
Article
Optics
Meng Zhang, JunMing Huang, XunYa Jiang
Summary: Frequency-sensitive super-collimation (FSSC) is a dispersion phenomenon in photonic crystals (PhCs) that allows beam collimating propagation with high frequency sensitivity. This study investigates the geometry of the dispersion surface in detail to understand the origin and stability of FSSC in a wide parameter space. Four features of the special geometry supporting FSSC are found in rectangular PhCs. The geometry is analyzed using the two-parameter modulation (TPM) method, and its origin and evolution are explained by changes in the field distribution of Bloch modes at high-symmetry points. The geometry not only explains the origin and stability of FSSC but also helps in discovering other FSSC phenomena.
Article
Mathematics
Soo-Ho Jo, Donghyu Lee, Byeng D. Youn
Summary: This research extends PnC design to include double piezoelectric defects, allowing ultrasonic actuators to operate effectively across multiple frequencies. An analytical model is used to predict wave-excitation performance, and a comprehensive study analyzes the impact of changes in input voltage configurations on output responses.
Article
Engineering, Multidisciplinary
Xuan-Bo Miao, H. W. Dong, Yue-Sheng Wang
Summary: This article develops a method for dispersion engineering in phononic crystals using deep neural networks and genetic algorithm. The method utilizes a high-precision DNN model to predict the energy band bounds of the crystals and combines it with genetic algorithm for inverse design. The proposed method is efficient, accurate, and scalable.
ENGINEERING OPTIMIZATION
(2023)
Article
Physics, Applied
Xiao-Lei Tang, Tian-Xue Ma, Yue-Sheng Wang
Summary: In this work, the topological rainbow trapping and energy amplification of acoustic waves in a gradient phononic crystal structure is investigated numerically and experimentally. Topological interface states (TISs) are generated along the interface between two phononic crystals with different topological phases due to the acoustic valley Hall effect. Rainbow trapping is achieved by introducing gradient into a 3D-printed phononic crystal structure by varying the geometrical parameter of scatterers along the interface. Incident acoustic waves at different frequencies split, stop, and are significantly amplified at different positions. Importantly, the rainbow trapping of TISs is immune to random structural disorders. The topological rainbow trapping shows promise for the design of broadband energy harvesters with excellent robustness.
APPLIED PHYSICS LETTERS
(2023)
Review
Materials Science, Multidisciplinary
Christabel Choi, Shubhi Bansal, Niko Munzenrieder, Sriram Subramanian
Summary: Acoustic metamaterials and phononic crystals have the potential to revolutionize human interactions and sensory communications. Understanding the fundamental theory and design principles alone is not enough; physical realization of these structures through fabrication and assembly is equally important. The paper critically examines fabrication and assembly approaches, addressing crucial parameters for efficient structural implementation. Various assembly techniques are proposed, uncovering innovative designs and supporting a fresh paradigm for innovation.
ADVANCED ENGINEERING MATERIALS
(2021)
Article
Chemistry, Physical
Xiaodong Wen, Lei Kang, Xiaowei Sun, Ting Song, Liangwen Qi, Yue Cao
Summary: In this paper, an improved adaptive genetic algorithm is proposed for the reverse customization of two-dimensional phononic crystals designed to maximize the relative bandwidth at low frequencies. The energy band dispersion relation and transmission loss of the optimal structure are calculated, and the effective wave-attenuation effect in the bandgap range is verified. This provides a solution for the custom-made design of acoustic metamaterials with excellent low-frequency bandgap sound insulation or other engineering applications.
Article
Physics, Multidisciplinary
M. Alinejad, A. Bahrami
Summary: This study presents the design procedure for an ultrasonic two-channel thermo-switch consisting of two line-defect waveguides coupled through four similar composite lattices on a two-dimensional fluid/fluid phononic crystal platform. The addition of an appropriate scatterer at the center of the structure can reduce scattering loss and enhance confinement and wave propagation efficiency. This is the first proposal of a 2 x 2 ultrasonic switch in two-dimensional fluid/fluid phononic crystals with composite lattice.
Article
Crystallography
Jianning Han, Guodong Hao, Wenying Yang, Xinsa Zhao
Summary: In the field of industrial structure detection, acoustic signals play a pivotal role. This study proposes a structure (PC-Mie) that couples phononic crystal (PC) point defects and Mie resonance structures (Mies) to enhance weak effective signals from complex environments. Numerical and experimental studies demonstrate that the PC-Mie can effectively enhance the energy of specific sound frequencies in complex air environments, making it suitable for collecting high-sensitivity acoustic signals. This research has significant implications for the development of weak acoustic signal detection technology and the application of self-powered sensors.
