Single shot low-coherence digital interferometer with multi-reflection reference mirror for measuring long depth object

2020 ◽  
Author(s):  
Quang Duc Pham ◽  
Yoshio Hayasaki
Keyword(s):  
Single Shot ◽  
Reference Mirror ◽  
Low Coherence

Single-shot low coherence pointwise measuring interferometer with potential for in-line inspection

2016 ◽  
Vol 28 (2) ◽  
pp. 025009 ◽  
Author(s):  
R Hahn ◽  
J Krauter ◽  
K Körner ◽  
M Gronle ◽  
W Osten
Keyword(s):  
Single Shot ◽  
Low Coherence

Low-coherence digital holography with a multireflection reference mirror

2020 ◽  
Vol 45 (16) ◽  
pp. 4393
Author(s):  
Quang Duc Pham ◽  
Yoshio Hayasaki
Keyword(s):  
Digital Holography ◽  
Reference Mirror ◽  
Low Coherence

Three-Dimensional Reconstruction by Time-Domain Optical Coherence Tomography Microscope with Improved Measurement Range

2017 ◽  
Vol 11 (5) ◽  
pp. 787-794
Author(s):  
Shin Usuki ◽  
Katsuaki Tamaki ◽  
Kenjiro T. Miura ◽  
◽  
Keyword(s):  
Optical Coherence Tomography ◽  
3D Reconstruction ◽  
Time Domain ◽  
Interference Fringe ◽  
Measurement Accuracy ◽  
Three Dimensional ◽  
Measurement Range ◽  
Optical Coherence ◽  
Reference Mirror ◽  
Low Coherence

The objective of this research was to develop a three-dimensional (3D) reconstruction system based on a time-domain optical coherence tomography (OCT) microscope. One of the critical drawbacks of OCT microscopes is that their axial measurement ranges are typically limited by their depths of field (DOFs), which are determined by the numerical apertures of their objective lenses and the central wavelengths of their light sources. If a low-coherence interference fringe is far outside the DOF, the measurement accuracy inevitably decreases, regardless of how well-adjusted the reference mirror is. To address this issue and improve the axial measurement range of the OCT microscope in this study, an object-scanning measurement scheme involving a Linnik interferometer was developed. To calibrate the system in the proposed technique, image post-processing is performed for a well-conditioned state to ensure that a low-coherence interference fringe is generated within the DOF, enabling 3D objects with high-aspect-ratio structures to be scanned along the axial direction. During object-scanning, this state is always monitored and is corrected by adjusting the reference mirror. By using this method, the axial measurement range can be improved up to the working distance (WD) of the objective lens without compromising the measurement accuracy. The WD is typically longer than 10 mm, while the DOF of the microscope is around 0.01 mm in general, although it varies depending on the imaging system. In this report, the experimental setup of a 3D reconstruction system is presented, a series of experimental verifications is described, and the results are discussed. The axial measurement range was improved to at least 35 times that of a typical OCT microscope with identical imaging optics.

Profilometry with compact single-shot low-coherence time-domain interferometry

2008 ◽  
Vol 281 (18) ◽  
pp. 4566-4571 ◽  
Author(s):  
Molly Subhash Hrebesh ◽  
Yuuki Watanabe ◽  
Manabu Sato
Keyword(s):  
Time Domain ◽  
Coherence Time ◽  
Single Shot ◽  
Low Coherence

scholarly journals Non-contact single shot elastography using line field low coherence holography

2016 ◽  
Vol 7 (8) ◽  
pp. 3021 ◽  
Author(s):  
Chih-Hao Liu ◽  
Alexander Schill ◽  
Chen Wu ◽  
Manmohan Singh ◽  
Kirill V. Larin
Keyword(s):  
Single Shot ◽  
Line Field ◽  
Low Coherence

scholarly journals Low-Coherence Shearing Interferometry With Constant Off-Axis Angle

2021 ◽  
Vol 8 ◽  
Author(s):  
Rongli Guo ◽  
Itay Barnea ◽  
Natan T. Shaked
Keyword(s):  
Human Sperm ◽  
Optical Path Difference ◽  
Wide Field ◽  
Phase Imaging ◽  
Single Shot ◽  
Interferometric Imaging ◽  
Coherent Noise ◽  
Shearing Interferometry ◽  
Quantitative Phase ◽  
Low Coherence

We present a wide-field interferometric imaging module for biomedical and metrological measurements, employing shearing interferometry with constant off-axis angle (SICA) that can work, for the first time, with a low-coherence light source. In the SICA module, the shearing distance between the interfering beams can be fully controlled without a direct relation with the off-axis angle. In contrast to our previous SICA module, here we use a low-coherence illumination source, providing quantitative phase profiles with significantly lower spatial coherent noise. Although a low-coherence source is used, we obtain off-axis interference on the entire camera sensor, where the optical path difference between the two beams is compensated by using a glass window positioned in the confocal plane. This highly stable, common-path, low-coherence, single-shot interferometric module can be used as an add-on unit to a conventional bright-field microscope illuminated by a low-coherence source. We demonstrate the advantages of using the module by quantitative phase imaging of a polymer bead, fluctuations in a human white blood cell, and dynamics of human sperm cells.

Heterodyne processing scheme for low coherence interferometric sensor systems

1991 ◽  
Vol 138 (6) ◽  
pp. 393
Author(s):  
B.T. Meggitt ◽  
W.J.O. Boyle ◽  
K.T.V. Grattan ◽  
A.E. Baruch ◽  
A.W. Palmer
Keyword(s):  
Sensor Systems ◽  
Processing Scheme ◽  
Low Coherence ◽  
Interferometric Sensor
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