scholarly journals Dual Photonic–Phononic Crystal Slot Nanobeam with Gradient Cavity for Liquid Sensing

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 421 ◽  
Author(s):  
Nan-Nong Huang ◽  
Yi-Cheng Chung ◽  
Hsiao-Ting Chiu ◽  
Jin-Chen Hsu ◽  
Yu-Feng Lin ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
The Finite Element Method ◽  
Concentrate Energy ◽  
Abrupt Changes ◽  
Analyte Solution ◽  
Liquid Sensing ◽  
Sensing Performance

A dual photonic–phononic crystal slot nanobeam with a gradient cavity for liquid sensing is proposed and analyzed using the finite-element method. Based on the photonic and phononic crystals with mode bandgaps, both optical and acoustic waves can be confined within the slot and holes to enhance interactions between sound/light and analyte solution. The incorporation of a gradient cavity can further concentrate energy in the cavity and reduce energy loss by avoiding abrupt changes in lattices. The newly designed sensor is aimed at determining both the refractive index and sound velocity of the analyte solution by utilizing optical and acoustic waves. The effect of the cavity gradient on the optical sensing performance of the nanobeam is thoroughly examined. By optimizing the design of the gradient cavity, the photonic–phononic sensor has significant sensing performances on the test of glucose solutions. The currently proposed device provides both optical and acoustic detections. The analyte can be cross-examined, which consequently will reduce the sample sensing uncertainty and increase the sensing precision.

Wave bandgap formation and its evolution in two-dimensional phononic crystals composed of rubber matrix with periodic steel quarter-cylinders

2018 ◽  
Vol 32 (04) ◽  
pp. 1850037 ◽  
Author(s):  
Peng Li ◽  
Guan Wang ◽  
Dong Luo ◽  
Xiaoshan Cao
Keyword(s):  
Finite Element Method ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
Rubber Matrix ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Defect States ◽  
Low Frequencies ◽  
High Frequencies ◽  
Inner Region

The band structure of a two-dimensional phononic crystal, which is composed of four homogenous steel quarter-cylinders immersed in rubber matrix, is investigated and compared with the traditional steel/rubber crystal by the finite element method (FEM). It is revealed that the frequency can then be tuned by changing the distance between adjacent quarter-cylinders. When the distance is relatively small, the integrality of scatterers makes the inner region inside them almost motionless, so that they can be viewed as a whole at high-frequencies. In the case of relatively larger distance, the interaction between each quarter-cylinder and rubber will introduce some new bandgaps at relatively low-frequencies. Lastly, the point defect states induced by the four quarter-cylinders are revealed. These results will be helpful in fabricating devices, such as vibration insulators and acoustic/elastic filters, whose band frequencies can be manipulated artificially.

TUNABLE BAND STRUCTURES OF 2D MULTI-ATOM ARCHIMEDEAN-LIKE PHONONIC CRYSTALS

2012 ◽  
Vol 01 (02) ◽  
pp. 1250016 ◽  
Author(s):  
Y. L. XU ◽  
C. Q. CHEN ◽  
X. G. TIAN
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Two Dimensional ◽  
Primitive Cell ◽  
The Finite Element Method ◽  
Band Structures ◽  
Solid System

Two dimensional multi-atom Archimedean-like phononic crystals (MAPCs) can be obtained by adding "atoms" at suitable positions in primitive cells of traditional simple lattices. Band structures of solid-solid and solid-air MAPCs are computed by the finite element method in conjunction with the Bloch theory. For the solid-solid system, our results show that the MAPCs can be suitably designed to split and shift band gaps of the corresponding traditional simple phononic crystal (i.e., with only one scatterer inside a primitive cell). For the solid-air system, the MAPCs have more and wider band gaps than the corresponding traditional simple phononic crystal. Numerical calculations for both solid-solid and solid-air MAPCs show that the band gap of traditional simple phononic crystal can be tuned by appropriately adding "atoms" into its primitive cell.

Tunable Band Gaps of Acoustic Waves in Two-Dimensional Phononic Crystals With Reticular Band Structures

2009 ◽  
Author(s):  
Zi-Gui Huang ◽  
Yunn-Lin Hwang ◽  
Pei-Yu Wang ◽  
Yen-Chieh Mao
Keyword(s):  
Acoustic Waves ◽  
Composite Structures ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Sound Insulation ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Elastic Band ◽  
Band Structures ◽  
Elastic Band Gaps

The excellent applications and researches of so-called photonic crystals raise the exciting researches of phononic crystals. By the analogy between photon and phonon, repetitive composite structures that are made up of different elastic materials can also prevent elastic waves of some certain frequencies from passing by, i.e., the frequency band gap features also exist in acoustic waves. In this paper, we present the results of the tunable band gaps of acoustic waves in two-dimensional phononic crystals with reticular band structures using the finite element method. Band gaps variations of the bulk modes due to different thickness and angles of reticular band structures are calculated and discussed. The results show that the total elastic band gaps for mixed polarization modes can be enlarged or reduced by adjusting the orientation of the reticular band structures. The phenomena of band gaps of elastic or acoustic waves can potentially be utilized for vibration-free, high-precision mechanical systems, and sound insulation.

Ladder Type of Leaky Surface Acoustic Waves Filters on Substrate of Lithium Niobate

2021 ◽  
Vol 23 (3) ◽  
pp. 139-147
Author(s):  
A.S. Koigerov ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Acoustic Waves ◽  
Communication Systems ◽  
Surface Acoustic Waves ◽  
Bandpass Filters ◽  
The Finite Element Method ◽  
Frequency Responses ◽  
Method Of Extraction ◽  
Element Method

High requirements on the electrical parameters of the filters are made in wireless radio communication systems. A number of tasks require bandpass filters with relative bandwidths of 8-12 %. In this case, the filter must have insertion losses of not more than 10 dB, have a rejection is not worse than 40 dB, unevenness in the bandwidth of not more than 1 dB. In addition, the amplitude frequency responses of the filter must have steep slopes due to the closely spaced frequency bands of neighboring communication systems. Due to its small size and other advantages, ladder resonator filters on surface acoustic waves are widely used in communication systems. To realize the high requirements of this type of filters, it is necessary not only to select all the topology parameters of the individual resonators included in the filter very accurately, but also to have a good computational theory and the necessary material parameters for the selected model at the design stage. Purpose: to show on the example of comparison of calculated and experimental frequency responses of ladder filters the validity of the method of extraction of the necessary parameters obtained for an infinite periodic structure by the finite element method for calculating of finite structures of real inter digital transducer and reflective gratings. Results: the method of extraction of parameters necessary for calculation by the method of connected modes on the basis of P-matrices is offered. The technique is based on the analysis of infinite periodic electrodes by the finite element method. Bandpass filters with a relative bandwidth 8-12 % on a piezosubstrate 49° YX LiNbO3 were designed and manufactured based on the proposed theory. It is shown that for this material, the calculation must take into account the direct radiation of bulk acoustic waves, since the design of ladder type filters, the radiation falls into the projected bandwidth of the filters. These calculations are confirmed by the results of experiments.

Full Band-Gap Silicon Phononic Crystals for Surface Acoustic Waves

2006 ◽  
Author(s):  
Saeed Mohammadi ◽  
Abdelkrim Khelif ◽  
Ryan Westafer ◽  
Eric Massey ◽  
William D. Hunt ◽  
...  
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Surface Acoustic Waves ◽  
Hexagonal Lattice ◽  
Phononic Crystals ◽  
Bulk Wave ◽  
Filling Fraction ◽  
Phononic Band Gap ◽  
Wide Range

Periodic elastic structures, called phononic crystals, show interesting frequency domain characteristics that can greatly influence the performance of acoustic and ultrasonic devices for several applications. Phononic crystals are acoustic counterparts of the extensively-investigated photonic crystals that are made by varying material properties periodically. Here we demonstrate the existence of phononic band-gaps for surface acoustic waves (SAWs) in a half-space of two dimensional phononic crystals consisting of hexagonal (honeycomb) arrangement of air cylinders in a crystalline Silicon background with low filling fraction. A theoretical calculation of band structure for bulk wave using finite element method is also achieved and shows that there is no complete phononic band gap in the case of the low filling fraction. Fabrication of the holes in Silicon is done by optical lithography and deep Silicon dry etching. In the experimental characterization, we have used slanted finger interdigitated transducers deposited on a thin layer of Zinc oxide (sputtered on top of the phononic crystal structure to excite elastic surface waves in Silicon) to cover a wide range of frequencies. We believe this to be the first reported demonstration of phononic band-gap for SAWs in a hexagonal lattice phononic crystal at such a high frequency.

Research on the large band gaps in multilayer radial phononic crystal structure

2016 ◽  
Vol 30 (10) ◽  
pp. 1650108 ◽  
Author(s):  
Nansha Gao ◽  
Jiu Hui Wu ◽  
Dong Guan
Keyword(s):  
Crystal Structure ◽  
Finite Element Method ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Transmission Spectra ◽  
Intermediate Mass ◽  
Displacement Fields ◽  
Vibration Coupling ◽  
Single Material

In this paper, we study the band gaps (BGs) of new proposed radial phononic crystal (RPC) structure composed of multilayer sections. The band structure, transmission spectra and eigenmode displacement fields of the multilayer RPC are calculated by using finite element method (FEM). Due to the vibration coupling effects between thin circular plate and intermediate mass, the RPC structure can exhibit large BGs, which can be effectively shifted by changing the different geometry values. This study shows that multilayer RPC can unfold larger and lower BGs than traditional phononic crystals (PCs) and RPC can be composed of single material.

scholarly journals Study of Acoustic Waves in a Teaching Classroom using Finite Element Method

2021 ◽  
pp. 65-75
Author(s):  
C. A. Wilson Bárcenas ◽  
J. M. Horta Rangel ◽  
M. A. Pérez Lara y Hernández ◽  
J. B. Hernández Zaragoza ◽  
M. L. Pérez Rea ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Acoustic Waves ◽  
Continuous Medium ◽  
The Finite Element Method ◽  
Computational Tools ◽  
Internal Surfaces ◽  
Engineering Department ◽  
Acoustic Physics ◽  
Element Method

Aims: To understand the behavior of acoustic waves in a specific classroom in order to get a configuration of panels and ceilings configuration to improve reception and clarity of internal sounds. This was possible by the modification of the properties of the enclosure, sush as the absorption coefficients of internal surfaces. The analysis was carried out through the implementation of a model by using Finite Element Method. Study Design: The acoustic behavior that enclosure for academic use require is discussed, indicating that it is common to find deficiencies in the acoustic architecture of enclosures, and the risks that this causes to cognitive and academic development, as a consequence of low understanding. Place and Duration of Study: Graduate Engineering Department, Universidad Autónoma de Querétaro, between August 2020 and June 2021. Methodology: The problem is solved by applying the finite element method. This implies that the essential concepts for the understanding of this subject are reviewed, such as; acoustic physics, mechanics of the continuous medium and finite element method. Results: After multiple analized scenarios, it was observed that while there is an absorption greater than the surface, the material of the panel or ceiling is not relevant. On the other hand, the size and surface where is located the panels turned out to be more relevant parameters. Conclusion: Considering the proposed alternatives, an increase in the Sound Pressure Level and a uniform distribution can be observed. The use of computational tools help to understand the behavior and distribution of acoustic waves in the classroom, which can provide an overview of different adaptations.

Surface Acoustic Wave Band Gaps and Phononic Structures on Thin Solid Plates

2005 ◽  
Author(s):  
Xinya Zhang ◽  
Ted Jackson ◽  
Emmanuel Lafound ◽  
Pierre Deymier ◽  
Jerome Vasseur
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Surface Acoustic Waves ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Laser Ultrasonics ◽  
Thin Plates ◽  
Wave Band

Novel phononic crystal structures on thin plates for material science applications in ultrasonic range (~ MHz) are described. Phononic crystals are created by a periodic arrangement of two or more materials displaying a strong contrast in their elastic properties and density. Because of the artificial periodic elastic structures of phononic crystals, there can exist frequency ranges in which waves cannot propagate, giving rise to phononic band gaps which are analogous to photonic band gaps for electromagnetic waves in the well-documented photonic crystals. In the past decades, the phononic structures and acoustic band gaps based on bulk materials have been researched in length. However few investigations have been performed on phononic structures on thin plates to form surface acoustic wave band gaps. In this presentation, we report a new approach: patterning two dimensional membranes to form phononic crystals, searching for specific acoustic transport properties and surface acoustic waves band gaps through a series of deliberate designs and experimental characterizations. The proposed phononic crystals are numerically simulated through a three-dimensional plane wave expansion (PWE) method and experimentally characterized by a laser ultrasonics instrument that has been developed in our laboratory.

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