scholarly journals Controllable axial optical chain beams using holographic method

2021 ◽  
Author(s):  
Xianlin Song ◽  
Jianshuang Wei ◽  
Ao Teng ◽  
Aojie Zhao
Keyword(s):  
Holographic Method

scholarly journals Combined Reduced Phase Dual-Directional Illumination Digital Holography and Speckle Displacements for Shape Measurement

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Davood Khodadad
Keyword(s):  
Phase Difference ◽  
Digital Holography ◽  
Relative Phase ◽  
Groove Depth ◽  
Phase Unwrapping ◽  
Shape Measurement ◽  
Phase Ambiguity ◽  
Holographic Method ◽  
Height Range ◽  
Phase Differences

We present a digital holographic method to increase height range measurement with a reduced phase ambiguity using a dual-directional illumination. Small changes in the angle of incident illumination introduce phase differences between the recorded complex fields. We decrease relative phase difference between the recorded complex fields 279 and 139 times by changing the angle of incident 0.5° and 1°, respectively. A two cent Euro coin edge groove is used to measure the shape. The groove depth is measured as ≈300  μm. Further, numerical refocusing and analysis of speckle displacements in two different planes are used to measure the depth without a use of phase unwrapping process.

scholarly journals Digital Holographic Method for Piezoelectric Transformers Vibration Analysis

2013 ◽  
Vol 48 ◽  
pp. 00021
Author(s):  
Pavel Psota ◽  
Václav Kopecký ◽  
Vít Lédl ◽  
Roman Doleček
Keyword(s):  
Vibration Analysis ◽  
Holographic Method ◽  
Piezoelectric Transformers

Noncontact holographic method of measuring linear displacements

2003 ◽  
Vol 70 (6) ◽  
pp. 436
Author(s):  
V. E. Mandel' ◽  
A. Yu. Popov ◽  
A. V. Tyurin ◽  
Yu. B. Shugailo
Keyword(s):  
Holographic Method

Holographic Pattern Etching of Silicon—Carbide by Excimer Laser

1989 ◽  
Vol 158 ◽  
Author(s):  
M. Murahara ◽  
M. Yonekawa ◽  
K. Shirakawa
Keyword(s):  
Laser Beam ◽  
Present Method ◽  
Etching Rate ◽  
The Other ◽  
Laser Beams ◽  
Excimer Lasers ◽  
Holographic Method ◽  
Etching Depth ◽  
Krf Laser ◽  
193 Nm

ABSTRACTThe diffraction grating on SiC mirror was performed by a laser holographic method. In the present method, KrF laser and CIF3 was used for etchant gas. The ClF3 gas has an absorption band in the range between 200 and 400 nm. Therefore, CIF3 gas is effectively decomposed by the XeF, KrF and ArF excimer lasers' radiation. It is found that absorption of Si—C is about 50% in the range of between200 and 400 nm, and that the bonding energy of Si—C is lower than the photon energy of KrF laser beam. The above results indicate the direct decomposition of Si—Cbond. On the other hand, the threshold fluence energy for etching was 800 mJ/cm2 in 249 nm and in 193 nm as high as 7 J/cm2. In these results, the KrF laser is more effective than ArF laser. Then we applied KrF laser to crystalline SiC in an atmosphere of C1F3 gas. The divided two polarized KrF laser beams were interfered on the substrate. And the beams were used to photodissociated CIF3 gas in the proximity of substrate. Fluence of KrF laser beam was 1 J/cm2. The incidential angle of KrF laser beams was 20º and the grating gaps were 7170 Å, etching depth 1000 Å, and etching rate was 5 Å/pulse.

Formation of 3D structures in a volumetric photocurable material via a holographic method

2015 ◽  
Vol 119 (6) ◽  
pp. 1034-1037 ◽  
Author(s):  
N. D. Vorzobova ◽  
V. G. Bulgakova ◽  
V. O. Veselov
Keyword(s):  
Holographic Method ◽  
3D Structures

scholarly journals AMPLITUDE-PHASE DISTRIBUTION MEASUREMENT PLANE DIMENSIONS INFLUENCE ON THE HOLOGRAPHIC METHOD ANTENNA ARRAY RADIATION PATTERN RECONSTRUCTION ERRORS

Doklady BGUIR ◽  
2020 ◽  
pp. 5-13
Author(s):  
O. A. Yurtsev ◽  
R. Ch. Shimanouski
Keyword(s):  
Antenna Array ◽  
Radiation Pattern ◽  
Phase Distribution ◽  
Near Field ◽  
Amplitude Distribution ◽  
Holographic Method ◽  
Longitudinal Zone ◽  
Measurement Plane ◽  
Measurement Surface ◽  
The Cost

The article explores the holographic method of measuring the antenna pattern. A flat antenna array is used as the antenna under test, and a planar rectangular surface is used as the surface on which the amplitudephase distribution in the near field is measured. Using the example of a flat antenna array, we consider the influence of the size of the measurement surface of the amplitude-phase distribution of the field in a plane orthogonal to the reconstruction plane of the radiation pattern. Antenna emitters are excited with a combined amplitude distribution and linear phase distribution. The field in the longitudinal zone of the lattice is determined using the Kirchhoff integral. The reconstructed radiation patterns are estimated using the amplitude-phase distribution over the entire measurement plane in comparison with the array radiation pattern in the far zone. A numerical analysis of the influence on the errors in determining the parameters of the lattice radiation pattern using the holographic method is also carried out: the number of columns of the amplitude-phase distribution on the measurement plane, the position of this plane in three coordinates relative to the plane of the aperture of the lattice. It is shown that if the spacing of the points of measurement of the amplitude-phase distribution and the pitch of the lattice are equal, to restore the radiation pattern using the holographic method, it is sufficient to use one column of the amplitude-phase distribution on the measurement plane. This greatly simplifies and reduces the cost of the measurement process and the necessary equipment. Examples of determining errors in measuring the parameters of the antenna array when shifting the plane of measurement of the amplitude-phase distribution in three coordinates are given.

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