Three-dimensional acoustic sub-diffraction focusing by coiled metamaterials with strong absorption

2019 ◽  
Vol 7 (17) ◽  
pp. 5131-5138 ◽  
Author(s):  
Fuyin Ma ◽  
Jianyu Chen ◽  
Jiu Hui Wu
Keyword(s):  
Focal Spot ◽  
Three Dimensional ◽  
Homogeneous Medium ◽  
Diffraction Limit ◽  
Strong Absorption ◽  
Operating Wavelength

The diffraction limit restricts the smallest diameter of a wave's focal spot in a homogeneous medium to no less than half of the operating wavelength.

scholarly journals 1178 J, 527 nm near diffraction limited laser based on a complete closed-loop adaptive optics controlled off-axis multi-pass amplification laser system

2021 ◽  
Vol 9 ◽  
Author(s):  
Deen Wang ◽  
Xin Zhang ◽  
Wanjun Dai ◽  
Ying Yang ◽  
Xuewei Deng ◽  
...  
Keyword(s):  
Laser Beam ◽  
Adaptive Optics ◽  
Closed Loop ◽  
Focal Spot ◽  
Beam Quality ◽  
Laser System ◽  
Diffraction Limit ◽  
Kdp Crystal ◽  
Main Amplifier

Abstract A 1178 J near diffraction limited 527 nm laser is realized in a complete closed-loop adaptive optics (AO) controlled off-axis multi-pass amplification laser system. Generated from a fiber laser and amplified by the pre-amplifier and the main amplifier, a 1053 nm laser beam with the energy of 1900 J is obtained and converted into a 527 nm laser beam by a KDP crystal with 62% conversion efficiency, 1178 J and beam quality of 7.93 times the diffraction limit (DL). By using a complete closed-loop AO configuration, the static and dynamic wavefront distortions of the laser system are measured and compensated. After correction, the diameter of the circle enclosing 80% energy is improved remarkably from 7.93DL to 1.29DL. The focal spot is highly concentrated and the 1178 J, 527 nm near diffraction limited laser is achieved.

A three dimensional dark focal spot uniformly surrounded by light

2007 ◽  
Vol 279 (2) ◽  
pp. 229-234 ◽  
Author(s):  
Nándor Bokor ◽  
Nir Davidson
Keyword(s):  
Focal Spot ◽  
Three Dimensional

scholarly journals Investigation on Light Extraction Behavior of Surface Plasmon-Coupled Deep-Ultraviolet LED in Different Emission Directions

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 82
Author(s):  
Mei Ge ◽  
Yi Li ◽  
Youhua Zhu ◽  
Meiyu Wang
Keyword(s):  
Surface Plasmon ◽  
Three Dimensional ◽  
Strong Absorption ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Time Domain Simulation ◽  
Al Nanoparticles ◽  
Extraction Behavior ◽  
Deep Ultraviolet ◽  
Difference Time

The light extraction behavior of an AlGaN-based deep-ultraviolet LED covered with Al nanoparticles (NPs) is investigated by three-dimensional finite-difference time-domain simulation. For the transmission spectra of s- and p-polarizations in different emission directions, the position of maximum transmittance can be changed from (θ = 0°, λ = 273 nm) to (θ = 0°, λ = 286 nm) by increasing the diameter of Al NPs from 40 nm to 80 nm. In the direction that is greater than the critical angle, the transmittance of s-polarization is very small due to the strong absorption of Al NPs, while the transmittance spectrum of p-polarization can be observed obviously for the 80 nm Al NPs structure. For a ~284 nm AlGaN-based LED with surface plasmon (SP) coupling, although the luminous efficiency is significantly improved due to the improvement of the radiation recombination rate as compared with the conventional LED, the light extraction efficiency (LEE) is lower than 2.61% of the conventional LED without considering the lateral surface extraction and bottom reflection. The LEE is not greater than ~0.98% (~2.12%) for an SP coupling LED with 40 nm (80 nm) Al NPs. The lower LEE can be attributed to the strong absorption of Al NPs.

Three-Dimensional Nanothermometry Below The Diffraction Limit

2021 ◽  
Author(s):  
Jonas Thiem ◽  
Simon Spelthann ◽  
Joerg Neumann ◽  
Axel Ruehl ◽  
Detlev Ristau
Keyword(s):  
Three Dimensional ◽  
Diffraction Limit

Quadratic wavefront and traveltime approximations in inhomogeneous layered media with curved interfaces

Geophysics ◽  
1982 ◽  
Vol 47 (7) ◽  
pp. 1012-1021 ◽  
Author(s):  
Bjørn Ursin
Keyword(s):  
Taylor Series ◽  
Layered Medium ◽  
Source Region ◽  
Three Dimensional ◽  
Homogeneous Medium ◽  
Quadratic Approximation ◽  
Reference Source ◽  
Layered Model ◽  
Zero Offset ◽  
Receiver Point

A quadratic approximation for the square of the traveltime from a source region to a receiver region is given for a three‐dimensional (3-D) medium consisting of inhomogeneous layers with curved interfaces. The square of the traveltime, being a function of source and receiver coordinates, is developed in a Taylor series around a reference source and receiver point. The relationships of the traveltime parameters to the ray parameters and the wavefront curvature matrices are shown. Using midpoint, half‐offset coordinates gives a simplified traveltime function compared to using source‐receiver coordinates only in the case that the reference source point and the reference receiver point coincide (zero‐offset approximation). For a medium consisting of homogeneous layers with plane dipping interfaces, the traveltime approximation is further simplified. The derived traveltime approximation is shown to be exact for a reflection from a plane dipping interface in a homogeneous medium. Explicit expressions for the traveltime parameters in terms of the layer parameters are derived for a horizontally layered medium. The traveltime errors of two different approximations are compared for a given layered model in a numerical example.

An analysis of 2D and 3D multiple attenuation for a canonical example

Geophysics ◽  
2005 ◽  
Vol 70 (6) ◽  
pp. A13-A28 ◽  
Author(s):  
Luc T. Ikelle
Keyword(s):  
Free Surface ◽  
Inverse Scattering ◽  
Three Dimensional ◽  
Homogeneous Medium ◽  
Vertical Plane ◽  
Multiple Attenuation ◽  
Out Of Plane ◽  
Seismic Acquisition ◽  
2D And 3D ◽  
The Relationship

Three-dimensional formulations of free-surface multiple attenuation for multioffset seismic data are well known. They are not yet used in practice because they require very dense source-receiver coverage, which is still out of reach with existing seismic-acquisition systems. The development of alternative solutions based on 2D algorithms depends on our understanding of the relationship between 2D and 3D free-surface multiple-attenuation methods. This paper attempts to enhance this understanding by establishing the relationship between 2D and 3D inverse scattering free-surface multiple attenuation. A 3D model consisting of three scattering points (one scattered point located in the vertical plane containing the shooting line and the other two points outside this plane) in a homogeneous medium (for which the exact pressure field is analytically known) is used to show that the 2D inverse scattering multiple-attenuation algorithm predicts all free-surface multiples as does its 3D counterpart but with some traveltime and amplitude errors. One implication of this result is that the current 2D inverse scattering multiple-attenuation algorithm, with an appropriate 2D-to-3D correction, can be used to predict the free-surface multiples for data containing out-of-plane scattering.

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