Analysis of micro-Fresnel lenses with local grating theory and its comparison with fully electromagnetic methods

2009 ◽  
Vol 26 (9) ◽  
pp. 1938 ◽  
Author(s):  
Hiroyuki Ichikawa ◽  
Koji Masuda ◽  
Takeshi Ueda
Keyword(s):  
Electromagnetic Methods ◽  
Fresnel Lenses

Electromagnetic methods in nondestructive testing of materials

2003 ◽  
Vol 16 (1) ◽  
pp. 1-23
Author(s):  
Konstanty Gawrylczyk
Keyword(s):  
Sensitivity Analysis ◽  
Finite Elements ◽  
Nondestructive Testing ◽  
Eddy Current ◽  
Quality Evaluation ◽  
Leakage Flux ◽  
Electromagnetic Methods ◽  
Conducting Materials ◽  
Inductive Methods ◽  
Flux Probe

The article deals with progress in electromagnetic methods used for quality evaluation of conducting materials. The term "electromagnetic methods" covers the following areas: magneto-inductive methods, magnetic leakage flux probe method, magnetometer principle and eddy-current methods. For the aim of numerical cracks recognition the sensitivity analysis with finite elements was shown.

Highly Efficient Dual-Fiber Optical Trapping with 3D Printed Diffractive Fresnel Lenses

ACS Photonics ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 88-97 ◽  
Author(s):  
Asa Asadollahbaik ◽  
Simon Thiele ◽  
Ksenia Weber ◽  
Aashutosh Kumar ◽  
Johannes Drozella ◽  
...  
Keyword(s):  
Optical Trapping ◽  
Highly Efficient ◽  
Fiber Optical ◽  
Fresnel Lenses ◽  
3D Printed

Amplitude apodizers encoded onto Fresnel lenses implemented on a phase-only spatial light modulator

2001 ◽  
Vol 40 (14) ◽  
pp. 2316 ◽  
Author(s):  
Andrés Márquez ◽  
Claudio Iemmi ◽  
Juan C. Escalera ◽  
Juan Campos ◽  
Silvia Ledesma ◽  
...  
Keyword(s):  
Spatial Light Modulator ◽  
Light Modulator ◽  
Fresnel Lenses

The use and misuse of apparent resistivity in electromagnetic methods

Geophysics ◽  
1986 ◽  
Vol 51 (7) ◽  
pp. 1462-1471 ◽  
Author(s):  
Brian R. Spies ◽  
Dwight E. Eggers
Keyword(s):  
Apparent Resistivity ◽  
Early Time ◽  
Asymptotic Formulas ◽  
Voltage Response ◽  
Late Time ◽  
Induced Voltage ◽  
Resistivity Curve ◽  
Transient Electromagnetic ◽  
Electromagnetic Methods ◽  
Tem Method

Problems and misunderstandings arise with the concept of apparent resistivity when the analogy between an apparent resistivity computed from geophysical observations and the true resistivity structure of the subsurface is drawn too tightly. Several definitions of apparent resistivity are available for use in electromagnetic methods; however, those most commonly used do not always exhibit the best behavior. Many of the features of the apparent resistivity curve which have been interpreted as physically significant with one definition disappear when alternative definitions are used. It is misleading to compare the detection or resolution capabilities of different field systems or configurations solely on the basis of the apparent resistivity curve. For the in‐loop transient electromagnetic (TEM) method, apparent resistivity computed from the magnetic field response displays much better behavior than that computed from the induced voltage response. A comparison of “exact” and “asymptotic” formulas for the TEM method reveals that automated schemes for distinguishing early‐time and late‐time branches are at best tenuous, and those schemes are doomed to failure for a certain class of resistivity structures (e.g., the loop size is large compared to the layer thickness). For the magnetotelluric (MT) method, apparent resistivity curves defined from the real part of the impedance exhibit much better behavior than curves based on the conventional definition that uses the magnitude of the impedance. Results of using this new definition have characteristics similar to apparent resistivity obtained from time‐domain processing.

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