scholarly journals Near-field uniformity analysis and compensation for finite-sized beam combiner with the asymmetric layout

2020 ◽  
Vol 14 (13) ◽  
pp. 1671-1681
Author(s):  
Kaizi Hao ◽  
Zhuo Li ◽  
Xin Wang ◽  
Lang Zhou ◽  
Yiting Wang
Keyword(s):  
Near Field ◽  
Beam Combiner ◽  
Field Uniformity

Efficiently approximate method for near field uniformity evaluation of finite-sized multilayered dielectric plates

2015 ◽  
Vol 54 (2) ◽  
pp. 025109 ◽  
Author(s):  
Yi Tian ◽  
Hui Yan ◽  
Xin Wang ◽  
Li Zhang ◽  
Zhuo Li
Keyword(s):  
Approximate Method ◽  
Near Field ◽  
Field Uniformity

Experimental Study of Laser Amplifier Based on LDA Side-Pumping Nd:Glass

2013 ◽  
Vol 552 ◽  
pp. 361-366
Author(s):  
Ji Si Qiu ◽  
Zhong Wei Fan ◽  
Xiong Xin Tang ◽  
Wei Ran Lin
Keyword(s):  
Beam Quality ◽  
Near Field ◽  
Nanosecond Laser Pulse ◽  
Nanosecond Laser ◽  
Seed Pulse ◽  
Laser Amplifier ◽  
Light Modulator ◽  
Average Output ◽  
Side Pumping ◽  
Field Uniformity

A high beam quality and high stability laser amplifier baseing on LDA side-pumping Nd-Glass which applied to amplify a nanosecond laser pulse source has been developed in the paper. In addition, Liquid crystal spatial light modulator is used in the amplifier for spatial beam shaping so as to improve the near-field uniformity. When the flat top pules with the pulse width of 3ns and energy of 500nJ are injected as the seed pulse, the average output energy of the laser amplifier is 100mJ. The modulation degree near field is less than 1.22:1, and the beam angle drifting of the far-field laser is less than 10 μrad.

Near-field scanning optical microscopy

1986 ◽  
Vol 44 ◽  
pp. 642-643
Author(s):  
E. Betzig ◽  
A. Harootunian ◽  
M. Isaacson ◽  
A. Lewis
Keyword(s):  
Near Field ◽  
Optical Microscope ◽  
Visible Radiation ◽  
Field Methods ◽  
Optical Elements ◽  
Optical Region ◽  
Order Of Magnitude ◽  
Nondestructive Imaging ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

In general, conventional methods of optical imaging are limited in spatial resolution by either the wavelength of the radiation used or by the aberrations of the optical elements. This is true whether one uses a scanning probe or a fixed beam method. The reason for the wavelength limit of resolution is due to the far field methods of producing or detecting the radiation. If one resorts to restricting our probes to the near field optical region, then the possibility exists of obtaining spatial resolutions more than an order of magnitude smaller than the optical wavelength of the radiation used. In this paper, we will describe the principles underlying such "near field" imaging and present some preliminary results from a near field scanning optical microscope (NS0M) that uses visible radiation and is capable of resolutions comparable to an SEM. The advantage of such a technique is the possibility of completely nondestructive imaging in air at spatial resolutions of about 50nm.

Principles of Planar Near-Field Antenna Measurements

2007 ◽  
Author(s):  
Stuart Gregson ◽  
John McCormick ◽  
Clive Parini
Keyword(s):  
Near Field ◽  
Antenna Measurements

Analysis of field uniformity and quantitative evaluation of subsurface pitting corrosion in conductors via GPEC

2020 ◽  
Vol 64 (1-4) ◽  
pp. 19-29
Author(s):  
Shuting Ren ◽  
Yong Li ◽  
Bei Yan ◽  
Jinhua Hu ◽  
Ilham Mukriz Zainal Abidin ◽  
...  
Keyword(s):  
Quantitative Evaluation ◽  
Eddy Current ◽  
Pitting Corrosion ◽  
Gradient Field ◽  
Uniform Field ◽  
Eddy Current Method ◽  
Optimal Position ◽  
Pulsed Eddy Current ◽  
Field Uniformity ◽  
Processing Algorithms

Structures of nonmagnetic materials are broadly used in engineering fields such as aerospace, energy, etc. Due to corrosive and hostile environments, they are vulnerable to the Subsurface Pitting Corrosion (SPC) leading to structural failure. Therefore, it is imperative to conduct periodical inspection and comprehensive evaluation of SPC using reliable nondestructive evaluation techniques. Extended from the conventional Pulsed eddy current method (PEC), Gradient-field Pulsed Eddy Current technique (GPEC) has been proposed and found to be advantageous over PEC in terms of enhanced inspection sensitivity and accuracy in evaluation and imaging of subsurface defects in nonmagnetic conductors. In this paper two GPEC probes for uniform field excitation are intensively analyzed and compared. Their capabilities in SPC evaluation and imaging are explored through simulations and experiments. The optimal position for deployment of the magnetic field sensor is determined by scrutinizing the field uniformity and inspection sensitivity to SPC based on finite element simulations. After the optimal probe structure is chosen, quantitative evaluation and imaging of SPC are investigated. Signal/image processing algorithms for SPC evaluation are proposed. Through simulations and experiments, it has been found that the T-shaped probe together with the proposed processing algorithms is advantageous and preferable for profile recognition and depth evaluation of SPC.

Immobilization of Radionuclides on Iron Canister Material at Simulated Near-field Conditions

2008 ◽  
Author(s):  
Daqing Cui ◽  
Ylva Ranebo ◽  
Jeanett Low ◽  
Vincenzo Rondinella ◽  
Jinshan Pan ◽  
...  
Keyword(s):  
Near Field ◽  
Field Conditions
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