Improvement of accuracy of interferometric measurement of wedge angle of plates
TL;DR: In this article, a method for improving the accuracy of measuring the wedge angle of transparent plates using a lateral-shear holographic interferometer is proposed, where successive processing of a pair of interferograms with doubled number of interference fringes leads to reduction of the observational error by a factor of two compared to traditional interferometric methods.
Abstract: A method is proposed for improving the accuracy of measuring the wedge angle of transparent plates using a lateral-shear holographic interferometer. Consecutive processing of a pair of interferograms with doubled number of interference fringes leads to reduction of the observational error by a factor of two compared to traditional interferometric methods. Data on the experimental validation of the method are presented.
Citations
More filters
TL;DR: In this paper, a modified self-reflection-mixing angle measurement system was proposed by combining a right-angle prism with a self-mixer for angle measurement, which achieved a resolution of 0.49mrad for a microchip solid-state laser and He-Ne laser.
Abstract: The self-mixing technique based on the traditional reflecting mirror has been demonstrated with great merit for angle sensing applications. Here we demonstrate a modified self-reflection-mixing angle measurement system by combine a right-angle prism to self-mixing angle measurement. In our system, the wavelength is crucial to the angle measurement resolution. For a microchip solid-state laser, the measurement resolution can reach 0.49 mrad, while the resolution for the He-Ne laser is 0.53 mrad. In addition, the ranges in the system with the microchip solid-state laser and He-Ne laser are up to 22 mrad and 24.9 mrad respectively. This modified angle measurement system effectively combines the advantage of self-mixing measurement system with a compact structure, providing interesting features such as of high requisition of resolution and precision.
16 citations
TL;DR: In this article, the authors used nonlinear recording of holograms of the reference and tested plates on different carriers and creating interference patterns that map the deviation of the angle, using higher orders of light diffraction on the holograms, with improved sensitivity.
Abstract: To improve the accuracy of the interferometric method of testing the wedge angle of a transparent plate, we propose using nonlinear recording of holograms of the reference and tested plates on different carriers and creating interference patterns that map the deviation of the angle, using higher orders of light diffraction on the holograms, with improved sensitivity. The increasing accuracy of the interferometric method of testing is provided by waves diffracted on holograms of the reference and tested plates in higher diffraction orders. Results of experimental testing of the method are presented.
3 citations
TL;DR: In this paper, a method for improving the sensitivity of measurements in the formation of aberration-free interference images of wedge plates, which do not require a priori knowledge of the position of the wedge edge, was proposed.
Abstract: We consider the method for improving the sensitivity of measurements in the formation of aberration-free interference images of wedge plates, which do not require a priori knowledge of the position of the wedge edge. It is shown that the sensitivity in the measurement of the wedge angle in real time interferometry is doubled in the case of recording on the reference hologram of the wedge plate followed by its reconstruction by the object light wave that has passed through the wedge plate rotated through 180° relative to the normal. It turns out that recording of a pair of holograms of the wedge plate, one of which is the image of the wedge plate turned through 180° relative to the normal to the plate, makes it possible to increase the sensitivity of measurements by more than an order of magnitude by eliminating the systematic components of measuring errors due to complete compensation of aberrations. The results of experimental testing of the method are considered.
3 citations
TL;DR: Despite the annoying time-dependent altitude fluctuation in measured wavefront topography, the optical homogeneity of the plate can be estimated from the increment on the average variance of the wavefront surface to its regression plane after the light passes through it by using the Bienaymé formula.
Abstract: By using a light-emitting diode as the probing light source and a Shack-Hartmann wavefront sensor as the recorder for the wavefront surface to execute a relative measurement, we present a useful method for determining the small wedge angle and optical homogeneity of a nominally planar glass plate from the wavefront measurements. The measured wavefront surface from the light source was first calibrated to be a horizontal plane before the plate under test was inserted. The wedge angle of the plate can be determined from the inclining angle of the regression plane of the measured wavefront surface after the plate was inserted between the light source and the wavefront sensor. Despite the annoying time-dependent altitude fluctuation in measured wavefront topography, the optical homogeneity of the plate can be estimated from the increment on the average variance of the wavefront surface to its regression plane after the light passes through it by using the Bienayme formula.
2 citations
TL;DR: In this article, the error in measuring small wedge angles of transparent plates by holographic reverse-shearing interferometry was reduced by formulating a pair of interference patterns using joint plate rotation and alternate tuning to an infinitely wide band in the right and left patterns.
Abstract: To reduce the error in measuring small wedge angles of transparent plates by holographic reverse-shearing interferometry, it is proposed to form a pair of interference patterns using joint plate rotation and alternate tuning to an infinitely wide band in the right and left patterns. The results of experimental approval of the method used to form interferograms of a glass plate with a small wedge angle, which indicate a higher sensitivity of this method and, as a consequence, a smaller measurement error, are presented.
2 citations
References
More filters
[...]
TL;DR: In this paper, a completely rewritten chapter was added to cover wavefront fitting and evaluation as well as holographic and Moire methods, and an appendix was added suggesting appropriate tests for typical optical surfaces.
Abstract: Fringe scanning techniques, now renamed heterodyning or phase shift interferometry, are covered in a completely rewritten chapter. New chapters have been added to cover wavefront fitting and evaluation as well as holographic and Moire methods. The chapter on parameter measurements has been completely rewritten and an appendix added suggesting appropriate tests for typical optical surfaces.
2,372 citations
TL;DR: In this article, a phase shifting Fizeau interferometry was used to measure the refractive index and wedge angle of transparent plates used as optical components in different experiments, and a near IR external cavity diode laser having spectral resolution up to 10−7 was employed to measure a test plate by introducing amplitude modulation technique.
Abstract: It is shown that Fizeau interferometry provides an accurate optical method to measure the refractive index and wedge angle of transparent plates used as optical components in different experiments. A near IR external cavity diode laser having spectral resolution up to 10−7 has been employed to measure the refractive index of the test plates by introducing amplitude modulation technique in the detection system of our phase shifting Fizeau interferometry. Detection of spatial fringes has been performed to find out the wedge angles of the plates by using a He–Ne laser along with the CCD-image sensor.
26 citations
TL;DR: In this paper, a general technique for determination of residual wedge angles of high optical quality parallel plates using a Fizeau interferometer is discussed, where the parallel plate to be tested for degrees of parallelism is used to introduce angular tilt in the fringes of an air cavity of a known wedge angle.
Abstract: A general technique for determination of residual wedge angles of high optical quality parallel plates using a Fizeau interferometer is discussed. In this technique the parallel plate to be tested for degrees of parallelism is used to introduce angular tilt in the Fizeau fringes of an air cavity of a known wedge angle. The parallelism is calculated from the angular tilt of the fringes. The technique is most suitable for highly par- allel transparent plates with very low residual wedge angles. © 2003 So-
19 citations