On the interpretation of laser interferometer fringe patterns

1969 ◽  
Vol 47 (5) ◽  
pp. 515-519 ◽  
Author(s):  
J. H. Williamson ◽  
S. S. Medley
Keyword(s):  
Frequency Response ◽  
Fringe Pattern ◽  
Laser Interferometer ◽  
Q Factor ◽  
Optical Length ◽  
External Resonator ◽  
Fabry Perot ◽  
Passive Technique ◽  
Fringe Patterns ◽  
Subsidiary Maxima

The frequency response of the laser interferometer is shown not to be limited by the Q-factor of the external resonator. However, at high fringing rates, the familiar Fabry–Perot fringes develop subsidiary maxima which make the fringe count liable to misinterpretation. This effect is minimized by using an external resonator with large losses. A passive technique employing an eighth-wave plate is described for determining the direction of change in the optical length directly from the fringe pattern.

scholarly journals Small-Sized Interferometer with Fabry–Perot Resonators for Gravitational Wave Detection

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1877
Author(s):  
Nikolai Petrov ◽  
Vladislav Pustovoit
Keyword(s):  
Correlation Function ◽  
Gravitational Waves ◽  
Laser Interferometer ◽  
Zero Order ◽  
Wave Detection ◽  
Resonant Modes ◽  
Fabry Perot ◽  
Spatially Distributed ◽  
Wave Laser ◽  
Higher Sensitivity

It is highly desirable to have a compact laser interferometer for detecting gravitational waves. Here, a small-sized tabletop laser interferometer with Fabry–Perot resonators consisting of two spatially distributed “mirrors” for detecting gravitational waves is proposed. It is shown that the spectral resolution of 10−23 cm−1 can be achieved at a distance between mirrors of only 1–3 m. The influence of light absorption in crystals on the limiting resolution of such resonators is also studied. A higher sensitivity of the interferometer to shorter-wave laser radiation is shown. A method for detecting gravitational waves is proposed based on the measurement of the correlation function of the radiation intensities of non-zero-order resonant modes from the two arms of the Mach–Zehnder interferometer.

scholarly journals Single-shot detection of 8 unique monochrome fringe patterns representing 4 distinct directions via multispectral fringe projection profilometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Parsa Omidi ◽  
Mohamadreza Najiminaini ◽  
Mamadou Diop ◽  
Jeffrey J. L. Carson
Keyword(s):  
Spatial Resolution ◽  
Fringe Pattern ◽  
Three Dimensional ◽  
Fringe Projection ◽  
Video Frame ◽  
Single Shot ◽  
Shot Detection ◽  
Fringe Patterns ◽  
Fringe Projection Profilometry ◽  
Multispectral Camera

AbstractSpatial resolution in three-dimensional fringe projection profilometry is determined in large part by the number and spacing of fringes projected onto an object. Due to the intensity-based nature of fringe projection profilometry, fringe patterns must be generated in succession, which is time-consuming. As a result, the surface features of highly dynamic objects are difficult to measure. Here, we introduce multispectral fringe projection profilometry, a novel method that utilizes multispectral illumination to project a multispectral fringe pattern onto an object combined with a multispectral camera to detect the deformation of the fringe patterns due to the object. The multispectral camera enables the detection of 8 unique monochrome fringe patterns representing 4 distinct directions in a single snapshot. Furthermore, for each direction, the camera detects two π-phase shifted fringe patterns. Each pair of fringe patterns can be differenced to generate a differential fringe pattern that corrects for illumination offsets and mitigates the effects of glare from highly reflective surfaces. The new multispectral method solves many practical problems related to conventional fringe projection profilometry and doubles the effective spatial resolution. The method is suitable for high-quality fast 3D profilometry at video frame rates.

Depth Detection of a Thin Aluminum Plate in Laser Ultrasonic Testing Using a Confocal Fabry-Perot Laser Interferometer

2011 ◽  
Vol 59 (5(1)) ◽  
pp. 3262-3266 ◽  
Author(s):  
Seung-Kyu Park ◽  
Sung-Hoon Baik ◽  
Hyun-Kyu Jung ◽  
Yong-Moo Cheong ◽  
Byung-Heon Cha ◽  
...  
Keyword(s):  
Ultrasonic Testing ◽  
Laser Interferometer ◽  
Aluminum Plate ◽  
Laser Ultrasonic ◽  
Thin Aluminum ◽  
Fabry Perot ◽  
Depth Detection

Multi-Frequency Heterodyne Phase Shift Technology in 3-D Measurement

2013 ◽  
Vol 774-776 ◽  
pp. 1582-1585 ◽  
Author(s):  
Le Wang ◽  
Lei Song ◽  
Li Jun Zhong ◽  
Peng Xin ◽  
Shuai Li ◽  
...  
Keyword(s):  
Phase Shift ◽  
Small Area ◽  
Fringe Pattern ◽  
Measurement Accuracy ◽  
High Efficiency ◽  
Median Filter ◽  
Distinct Advantage ◽  
Accuracy Measurement ◽  
Fringe Patterns ◽  
Spin Filtering

According to the characteristics of the fringe patterns noise, came up with a small area spin filtering noise cancellation algorithm based on parallel marker technology. It means that preprocess the fringe pattern before spin filtering, then did a median filter and calculated the stripe direction, finally used the extract the fringe direction to spin filtering of the original image. The algorithm can marked several targets in scanning process at the same time. So it has a high efficiency. The algorithm can be used in the multi-frequency heterodyne phase shift technology .And we can use the technology to complete the measurement of complex surfaces. Experimental results show that the method has a distinct advantage in measurement accuracy, measurement speed, and noise immunity.

scholarly journals Mode Suppression in Injection Locked Multi-Mode and Single-Mode Lasers for Optical Demultiplexing

Photonics ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 27 ◽  
Author(s):  
Kevin Shortiss ◽  
Maryam Shayesteh ◽  
William Cotter ◽  
Alison Perrott ◽  
Mohamad Dernaika ◽  
...  
Keyword(s):  
Active Material ◽  
Single Mode ◽  
Optical Filters ◽  
Optical Injection ◽  
Single Frequency ◽  
Q Factor ◽  
Monolithically Integrated ◽  
Mode Suppression ◽  
Locking Range ◽  
Fabry Perot

Optical injection locking has been demonstrated as an effective filter for optical communications. These optical filters have advantages over conventional passive filters, as they can be used on active material, allowing them to be monolithically integrated onto an optical circuit. We present an experimental and theoretical study of the optical suppression in injection locked Fabry–Pérot and slotted Fabry–Pérot lasers. We consider both single frequency and optical comb injection. Our model is then used to demonstrate that improving the Q factor of devices increases the suppression obtained when injecting optical combs. We show that increasing the Q factor while fixing the device pump rate relative to threshold causes the locking range of these demultiplexers to asymptotically approach a constant value.

scholarly journals The difference between the mechanical and optical lengths of a steel end-gauge

1929 ◽  
Vol 122 (789) ◽  
pp. 122-133 ◽  
Keyword(s):  
Optical Length ◽  
Interference Fringes ◽  
Light Waves ◽  
Fabry Perot ◽  
The Difference ◽  
Block Gauge

The two lapped surfaces whose separation defines the length of a good end-gauge or block-gauge generally approach a degree of optical flatness and parallelism sufficient for their use in interferometry. If, therefore, such a gauge is supported between the semi-transparent mirrors of a Fabry-Perot étalon of greater length than the gauge, with its surfaces parallel to the mirrors, the gauge may be standardised in terms of light waves by the methods usually applied to Fabry-Perot étalons. In fig. 1 L is the optical separation of the étalon mirrors, l 1 and l 2 are respectively the optical separations of a gauge surface and an adjacent étalon mirror at each end of the figure, and O is the optical length of the gauge: therefore O = L — ( l 1 + l 2 ), (1) L is measured either directly or indirectly in terms of light waves, the choice depending upon the magnitude of L, while both l 1 and l 2 are measured directly in terms of light waves by observation of the reflected system of circular interference fringes; thus O may be obtained in terms of light waves.

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