1
|
Gbur G. Visions of invisibility in optics: retrospective. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2024; 41:435-443. [PMID: 38437434 DOI: 10.1364/josaa.513961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 01/20/2024] [Indexed: 03/06/2024]
Abstract
Invisibility was long thought to be exclusively the domain of science fiction and fantasy authors, but in recent years it has been the subject of extensive theoretical and experimental research. In this retrospective we look back on the evolution of invisibility in science, from the earliest hints of invisible objects in the late 19th century up to the modern concepts of cloaking, and some of the connections between them.
Collapse
|
2
|
Li C, Xu L, Zhu L, Zou S, Liu QH, Wang Z, Chen H. Concentrators for Water Waves. PHYSICAL REVIEW LETTERS 2018; 121:104501. [PMID: 30240256 DOI: 10.1103/physrevlett.121.104501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Indexed: 06/08/2023]
Abstract
By introducing concepts from transformation optics to the manipulation of water waves, we design and experimentally demonstrate two annular devices for concentrating waves, which employ gradient depth profiles based on Fabry-Pérot resonances. Our measurements and numerical simulations confirm the concentrating effect of the annular devices and show that they are effectively invisible to the water waves. We show that transformation optics is thus an effective framework for designing devices to improve the efficiency of wave energy collection, and we expect potential applications in coastline ocean engineering.
Collapse
Affiliation(s)
- Chunyang Li
- Institute of Electromagnetics and Acoustics and Department of Electronic Science, Xiamen University, Xiamen 361005, China
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
| | - Lin Xu
- Institute of Electromagnetics and Acoustics and Department of Electronic Science, Xiamen University, Xiamen 361005, China
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
- Institute of Physical Science and Information Technology & Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, Hefei 230601, China
| | - Lili Zhu
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
| | - Siyuan Zou
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
| | - Qing Huo Liu
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Zhenyu Wang
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
| | - Huanyang Chen
- Institute of Electromagnetics and Acoustics and Department of Electronic Science, Xiamen University, Xiamen 361005, China
| |
Collapse
|
3
|
Tsang ACH, Shelley MJ, Kanso E. Activity-induced instability of phonons in 1D microfluidic crystals. SOFT MATTER 2018; 14:945-950. [PMID: 29319100 DOI: 10.1039/c7sm01335c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
One-dimensional crystals of passively-driven particles in microfluidic channels exhibit collective vibrational modes reminiscent of acoustic 'phonons'. These phonons are induced by the long-range hydrodynamic interactions among the particles and are neutrally stable at the linear level. Here, we analyze the effect of particle activity - self-propulsion - on the emergence and stability of these phonons. We show that the direction of wave propagation in active crystals is sensitive to the intensity of the background flow. We also show that activity couples, at the linear level, transverse waves to the particles' rotational motion, inducing a new mode of instability that persists in the limit of large background flow, or, equivalently, vanishingly small activity. We then report a new phenomenon of phonons switching back and forth between two adjacent crystals in both passively-driven and active systems, similar in nature to the wave switching observed in quantum mechanics, optical communication, and density stratified fluids. These findings could have implications for the design of commercial microfluidic systems and the self-assembly of passive and active micro-particles into one-dimensional structures.
Collapse
Affiliation(s)
- Alan Cheng Hou Tsang
- Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, California 90089, USA. and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Michael J Shelley
- Center for Computational Biology, Flatiron Institute, New York, New York 10010, USA and Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, USA
| | - Eva Kanso
- Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, California 90089, USA. and Center for Computational Biology, Flatiron Institute, New York, New York 10010, USA and Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, USA
| |
Collapse
|
4
|
Wang Z, Li C, Zatianina R, Zhang P, Zhang Y. Carpet cloak for water waves. Phys Rev E 2017; 96:053107. [PMID: 29347642 DOI: 10.1103/physreve.96.053107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Indexed: 06/07/2023]
Abstract
Cloaking is a challenging topic in the field of wave motion, and is of significant theoretical value. In this article, a type of carpet cloak has been theoretically designed for water waves by using the effective medium and transformation theory. This carpet cloak device, created by a three-dimensional printer, is composed of a periodic structure which realizes the equivalent anisotropic water depth. We demonstrate its excellent cloaking performance numerically and experimentally in a wide range of frequencies and angles of incidence, with low wave attenuation characteristics and simple device realization of this carpet cloak illustrating that water wave transformation is a powerful method with which to manipulate water waves.
Collapse
Affiliation(s)
- Zhenyu Wang
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Chunyang Li
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Razafizana Zatianina
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Pei Zhang
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Yongqiang Zhang
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, People's Republic of China
| |
Collapse
|
5
|
Couston LA, Guo Q, Chamanzar M, Alam MR. Fabry-Perot resonance of water waves. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:043015. [PMID: 26565340 DOI: 10.1103/physreve.92.043015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Indexed: 06/05/2023]
Abstract
We show that significant water wave amplification is obtained in a water resonator consisting of two spatially separated patches of small-amplitude sinusoidal corrugations on an otherwise flat seabed. The corrugations reflect the incident waves according to the so-called Bragg reflection mechanism, and the distance between the two sets controls whether the trapped reflected waves experience constructive or destructive interference within the resonator. The resulting amplification or suppression is enhanced with increasing number of ripples and is most effective for specific resonator lengths and at the Bragg frequency, which is determined by the corrugation period. Our analysis draws on the analogous mechanism that occurs between two partially reflecting mirrors in optics, a phenomenon named after its discoverers Charles Fabry and Alfred Perot.
Collapse
Affiliation(s)
- Louis-Alexandre Couston
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
| | - Qiuchen Guo
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
| | - Maysamreza Chamanzar
- Department of Electrical Engineering & Computer Sciences, University of California, Berkeley, California 94720, USA
| | - Mohammad-Reza Alam
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
| |
Collapse
|
6
|
Elandt RB, Shakeri M, Alam MR. Surface gravity-wave lensing. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:023012. [PMID: 25353576 DOI: 10.1103/physreve.89.023012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Indexed: 06/04/2023]
Abstract
Here we show that a nonlinear resonance between oceanic surface waves caused by small seabed features (the so-called Bragg resonance) can be utilized to create the equivalent of lenses and curved mirrors for surface gravity waves. Such gravity wave lenses, which are merely small changes to the seafloor topography and therefore are surface noninvasive, can focus or defocus the energy of incident waves toward or away from any desired focal point. We further show that for a broadband incident wave spectrum (i.e., a wave group composed of a multitude of different-frequency waves), a polychromatic topography (occupying no more than the area required for a monochromatic lens) can achieve a broadband lensing effect. Gravity wave lenses can be utilized to create localized high-energy wave zones (e.g., for wave energy harvesting or creating artificial surf zones) as well as to disperse waves in order to create protected areas (e.g., harbors or areas near important offshore facilities). In reverse, lensing of oceanic waves may be caused by natural seabed features and may explain the frequent appearance of very high amplitude waves in certain bodies of water.
Collapse
Affiliation(s)
- Ryan B Elandt
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
| | - Mostafa Shakeri
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
| | - Mohammad-Reza Alam
- Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA
| |
Collapse
|
7
|
Hu X, Yang J, Zi J, Chan CT, Ho KM. Experimental observation of negative effective gravity in water waves. Sci Rep 2013; 3:1916. [PMID: 23715132 PMCID: PMC3665962 DOI: 10.1038/srep01916] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 05/13/2013] [Indexed: 11/25/2022] Open
Abstract
The gravity of Earth is responsible for the formation of water waves and usually difficult to change. Although negative effective gravity was recently predicted theoretically in water waves, it has not yet been observed in experiments and remains a mathematical curiosity which is difficult to understand. Here we experimentally demonstrate that close to the resonant frequency of purposely-designed resonating units, negative effective gravity can occur for water waves passing through an array of resonators composing of bottom-mounted split tubes, resulting in the prohibition of water wave propagation. It is found that when negative gravity occurs, the averaged displacement of water surface in a unit cell of the array has a phase difference of π to that along the boundary of the unit cell, consistent with theoretical predictions. Our results provide a mechanism to block water waves and may find applications in wave energy conversion and coastal protection.
Collapse
Affiliation(s)
- Xinhua Hu
- Department of Materials Science, Key Laboratory of Micro- and Nano-Photonic Structures (Ministry of Education) and Laboratory of Advanced Materials, Fudan University, Shanghai, China.
| | | | | | | | | |
Collapse
|