Broadband two-dimensional planar luneburg lens composed of gradient index metamaterials

2014 ◽  
Author(s):  
Hao Yu ◽  
Xumin Ding ◽  
Qun Wu ◽  
Yuming Wu
Keyword(s):  
Gradient Index ◽  
Two Dimensional ◽  
Luneburg Lens

Acoustic Luneburg Lens as a New Sonar System

2015 ◽  
Vol 763 ◽  
pp. 101-104 ◽  
Author(s):  
Sang Hoon Kim
Keyword(s):  
Variable Density ◽  
Gradient Index ◽  
Two Dimensional ◽  
Frequency Range ◽  
Acoustic Source ◽  
Incoming Wave ◽  
Sonar System ◽  
Gradient Index Lens ◽  
Luneburg Lens ◽  
Strong Candidate

Luneburg lens is a gradient index lens that focuses the incoming wave to the opposite side of the lens without aberration. We developed a two-dimensional acoustic Luneburg lens by variable density method of space inside the lens. The lens is composed of hundreds of aluminum columns with various radii of less than 1cm. We tested the ability as sonar in the air. It focuses the incoming acoustic wave on the edge of the opposite side of the lens as well in the frequency range of 1,000Hz ~ 3,000Hz. It showed a dynamic response depending on the motion of the acoustic source. It could be a strong candidate of a next generation of sonar.

Optical Characterization of Silica Aerogel

1988 ◽  
Vol 121 ◽  
Author(s):  
Lawrence W. Hrubesh ◽  
Cynthia T. Alviso
Keyword(s):  
Silica Aerogel ◽  
Porous Silica ◽  
Optical Characterization ◽  
Optical Methods ◽  
Gradient Index ◽  
Two Dimensional ◽  
Two Dimensional Image ◽  
The Third ◽  
Third Dimension

ABSTRACTTwo optical methods are described for mapping the local variations of refractive index within monoliths of porous silica aerogel. One is an interferometrie measurement that produces “iso-index” fringes in a two dimensional image; an orthogonal view gives the third dimension information. The other method uses the deflection of a He-Ne laser beam to map the gradient index within a sample. The quantification of the measurements is described and the accuracy of the results is discussed.

Acoustic mirage in two-dimensional gradient-index phononic crystals

2009 ◽  
Vol 106 (5) ◽  
pp. 053529 ◽  
Author(s):  
Sz-Chin Steven Lin ◽  
Tony Jun Huang
Keyword(s):  
Phononic Crystals ◽  
Gradient Index ◽  
Two Dimensional

scholarly journals Discretization of two-dimensional Luneburg lens based on the correctional effective medium theory

2021 ◽  
Vol 29 (21) ◽  
pp. 33434
Author(s):  
Zhiwei Sun ◽  
Chao Liu ◽  
Ruolei Xu ◽  
Heling Gong ◽  
Xiaobo Xuan ◽  
...  
Keyword(s):  
Effective Medium Theory ◽  
Effective Medium ◽  
Two Dimensional ◽  
Medium Theory ◽  
Luneburg Lens
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