scholarly journals Acoustic Waves and Far- field Patterns in Two Dimensional Oceans with Porous- elastic Seabeds

1992 ◽  
Vol 22 (3-4) ◽  
pp. 685-700 ◽  
Author(s):  
R. P. Gilbert ◽  
Yongzhi Xu
Keyword(s):  
Acoustic Waves ◽  
Far Field ◽  
Two Dimensional ◽  
Field Patterns

Far-field focusing of acoustic waves by a two-dimensional phononic crystal with surface grating

2009 ◽  
Vol 87 (5) ◽  
pp. 57003 ◽  
Author(s):  
Zhaojian He ◽  
Xiaochun Li ◽  
Ke Deng ◽  
Jun Mei ◽  
Zhengyou Liu
Keyword(s):  
Acoustic Waves ◽  
Phononic Crystal ◽  
Far Field ◽  
Two Dimensional ◽  
Surface Grating

Far-field imaging of acoustic waves by a two-dimensional sonic crystal

2005 ◽  
Vol 71 (5) ◽  
Author(s):  
Chunyin Qiu ◽  
Xiangdong Zhang ◽  
Zhengyou Liu
Keyword(s):  
Acoustic Waves ◽  
Far Field ◽  
Two Dimensional ◽  
Sonic Crystal ◽  
Field Imaging

scholarly journals The determination of the surface impedance of an obstacle

1993 ◽  
Vol 36 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Andrzej W. Kȩdzierawski
Keyword(s):  
Acoustic Waves ◽  
Surface Impedance ◽  
Scattering Problem ◽  
Three Dimensional ◽  
Inverse Scattering Problem ◽  
Far Field ◽  
Field Patterns ◽  
Time Harmonic ◽  
Scattered Fields

The inverse scattering problem we consider is to determine the surface impedance of a three-dimensional obstacle of known shape from a knowledge of the far-field patterns of the scattered fields corresponding to many incident time-harmonic plane acoustic waves. We solve this problem by using both the methods of Kirsch-Kress and Colton-Monk.

Dense sets and far field patterns for acoustic waves in an inhomogeneous medium

1988 ◽  
Vol 31 (3) ◽  
pp. 401-407 ◽  
Author(s):  
David Colton
Keyword(s):  
Inhomogeneous Medium ◽  
Inverse Scattering ◽  
Acoustic Waves ◽  
Scattering Problem ◽  
Plane Waves ◽  
Related Result ◽  
Wave Number ◽  
Far Field ◽  
Field Patterns ◽  
Time Harmonic

In this paper, we shall obtain two results on the class of far field patterns corresponding to the scattering of time harmonic acoustic plane waves by an inhomogeneous medium of compact support. Although the problem of characterizing the class of far field patterns is of basic importance in inverse scattering theory, very little is known about this class other than the fact that the far field patterns are entire functions of their independent (complex) variables for each positive fixed value of the wave number. In particular, the class of far field patterns is not all of L2(∂Ω) where ∂Ω is the unit sphere and this implies that the inverse scattering problem is improperly posed since the far field patterns are, in practice, determined from inexact measurements. The purpose of this paper is to show that while the class of far field patterns corresponding to the scattering of time harmonic plane waves by an inhomogeneous medium is not all of L2(∂Ω), it is dense in L2(∂Ω) for sufficiently small values of the wave number. In addition, a related result will be obtained for a special translation of the class of far field patterns. Analogous results for the scattering of time harmonic acoustic waves by a homogeneous scattering obstacle have recently been obtained by Colton [1], Colton and Kirsch [2], Colton and Monk [3, 4] and Kirsch [8].

Far-Field Patterns for Acoustic Waves in an Inhomogeneous Medium

1989 ◽  
Vol 20 (6) ◽  
pp. 1472-1483 ◽  
Author(s):  
David Colton ◽  
Andreas Kirsch ◽  
Lassi Päivärinta
Keyword(s):  
Inhomogeneous Medium ◽  
Acoustic Waves ◽  
Far Field ◽  
Field Patterns

scholarly journals Axial localization and tracking of self-interference nanoparticles by lateral point spread functions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yongtao Liu ◽  
Zhiguang Zhou ◽  
Fan Wang ◽  
Günter Kewes ◽  
Shihui Wen ◽  
...  
Keyword(s):  
Mirror Image ◽  
Excitation Wavelength ◽  
Far Field ◽  
Point Spread Functions ◽  
Microscopy Imaging ◽  
Localization Accuracy ◽  
Field Patterns ◽  
Atomic Force ◽  
Point Spread ◽  
Sensing Technology

AbstractSub-diffraction limited localization of fluorescent emitters is a key goal of microscopy imaging. Here, we report that single upconversion nanoparticles, containing multiple emission centres with random orientations, can generate a series of unique, bright and position-sensitive patterns in the spatial domain when placed on top of a mirror. Supported by our numerical simulation, we attribute this effect to the sum of each single emitter’s interference with its own mirror image. As a result, this configuration generates a series of sophisticated far-field point spread functions (PSFs), e.g. in Gaussian, doughnut and archery target shapes, strongly dependent on the phase difference between the emitter and its image. In this way, the axial locations of nanoparticles are transferred into far-field patterns. We demonstrate a real-time distance sensing technology with a localization accuracy of 2.8 nm, according to the atomic force microscope (AFM) characterization values, smaller than 1/350 of the excitation wavelength.

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