Off-Axis Fresnel Digital Holography at Terahertz Frequencies

2016 ◽  
Author(s):  
Martin S. Heimbeck ◽  
Henry O. Everitt
Keyword(s):  
Digital Holography ◽  
Terahertz Frequencies

Digital holography with a set of two close wavelengths for height measurement of solder bumps

2020 ◽  
Vol 59 (SO) ◽  
pp. SOOE03
Author(s):  
Hiroyuki Ishigaki ◽  
Takahiro Mamiya ◽  
Yoshio Hayasaki
Keyword(s):  
Digital Holography ◽  
Height Measurement ◽  
Solder Bumps

Development of 72K Ultra-High-Resolution SLMoG system for high-capacity digital holography image

2019 ◽  
pp. 952
Author(s):  
Jae-Eun Pi ◽  
Ji-Hun Choi ◽  
Jong-Heon Yang ◽  
Chi-Young Hwang ◽  
Gi Heon Kim ◽  
...  
Keyword(s):  
High Resolution ◽  
Digital Holography ◽  
High Capacity

Modelling and simulation of novel liquid-infiltrated PCF biosensor in Terahertz frequencies

2020 ◽  
Vol 14 (6) ◽  
pp. 411-416
Author(s):  
Nurul Awadah Nadiah Binti Suhaimi ◽  
Izaddeen Kabir Yakasai ◽  
Emeroylariffion Abas ◽  
Shubi Kaijage ◽  
Feroza Begum
Keyword(s):  
Modelling And Simulation ◽  
Terahertz Frequencies

scholarly journals Estimation methods to extract complex permittivity from transmission coefficient in the terahertz band

2021 ◽  
Vol 53 (8) ◽  
Author(s):  
Chuang Yang ◽  
Jian Wang ◽  
Cheng Yang
Keyword(s):  
Transmission Coefficient ◽  
Iterative Algorithm ◽  
Complex Permittivity ◽  
Free Space ◽  
Estimation Methods ◽  
Extraction Technique ◽  
Initial Value ◽  
Terahertz Band ◽  
Terahertz Frequencies

AbstractIn this paper, the characteristics of the transmission coefficient (S$$_{21}$$ 21 ) measured in free-space at terahertz frequencies are analyzed. The analysis results are used to estimate the permittivity of the material under test, and the estimated permittivity is adopted as an initial-value for the iterative algorithm to extract the complex permittivity of the material from the S$$_{21}$$ 21 . The iterative extraction technique based on the estimation is efficient, while the iterative extraction technique without the estimation is inefficient. Various known materials in the literature are used to validate the technique in the terahertz band.

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.

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