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Proceedings ArticleDOI

Extraction of phase profile at discrete spatial frequency bands using phase shifting interferometry

TL;DR: In this paper, the phase information available in a desired band of spatial frequencies is extracted by placing the phase sample in the path of a converging beam of light entering a Mach Zehnder interferometer.
Abstract: In this paper, we report an interferometric method to extract the phase information available in a desired band of spatial frequencies. The phase sample is placed in the path of a converging beam of light entering a Mach Zehnder interferometer so that the two Fourier Transform (FT) planes are located in the two interferometer arms. One of the FT planes is filtered by suitable masks so that only the frequencies that are blocked appears in the final interferogram. An imaging lens images the phase object on a CCD. Polarization Phase Shifting is incorporated so that the final frequency filtered image is reconstructed from the four phase shifted interferograms. The interferometer is made to operate in null fringe condition so that residual phase is eliminated. Simulated and experimental results are presented.
Citations
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Journal ArticleDOI
15 Feb 2021
TL;DR: In this paper, the relationship of local birefringence and stress oriented inhomogeneous elasticity of a sample from the spatial frequency response of focused surface plasmon (FSP) was studied.
Abstract: In this paper, we study the relationship of local birefringence and stress oriented inhomogeneous elasticity of a sample from the spatial frequency response of focused surface plasmon (FSP). The birefringence of the sample varies the propagation constant of surface plasmon with regard to its direction and produces an elliptic absorption pattern in the reflected spatial frequency distribution. Birefringence is calculated from the ratio of the propagation constant along the fast to slow axis of the sample. The change in eccentricity was proportional to the applied stress on cellophane film. A strong correlation (0.94∼0.97) exists between FSP and phase shifting interferometry results.

5 citations


Cites background from "Extraction of phase profile at disc..."

  • ...However, determination of spatially varying retardance calls for special techniques [18,19,20]....

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References
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BookDOI
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

Journal ArticleDOI
TL;DR: By introducing the phase data of a third wavelength, one can measure the phase of a very steep wave front and the repeatability of the measurement is better than 25-A rms (λ = 6328 A).
Abstract: This paper describes a method to enhance the capability of two-wavelength phase-shifting interferometry. By introducing the phase data of a third wavelength, one can measure the phase of a very steep wave front. Experiments have been performed using a linear detector array to measure surface height of an off-axis parabola. For the wave front being measured the optical path difference between adjacent detector pixels was as large as 3.3 waves. After temporal averaging of five sets of data, the repeatability of the measurement is better than 25-A rms (λ = 6328 A).

309 citations


"Extraction of phase profile at disc..." refers methods in this paper

  • ...The basic methods of phase reconstruction are those of phase shifting [3] and Fourier transform [4]....

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Journal ArticleDOI
TL;DR: A Gerchberg-type iterative technique is used to eliminate edge effects in several types of interferogram and results are presented for seeing measurements and interferometric tests.
Abstract: Fourier transform techniques have been used to map the complex fringe visibility in several types of interferogram. A Gerchberg-type iterative technique is used to eliminate edge effects. Results are presented for two specific cases: seeing measurements and interferometric tests.

293 citations


"Extraction of phase profile at disc..." refers methods in this paper

  • ...The basic methods of phase reconstruction are those of phase shifting [3] and Fourier transform [4]....

    [...]

Journal ArticleDOI
TL;DR: In this article, a review of the literature concerning phase masks and attempt to bridge the gap between two instrumental systems in which they are often found: the Mach-Zehnder interferometer and the coronagraph is presented.
Abstract: Phase masks have numerous applications in astronomical optics, in particular related to two themes: coronagraphy for detection and analysis of extrasolar planets or circumstellar disks, and wavefront analysis for extremely precise adaptive optics systems or cophasing of segmented mirrors. I review some of the literature concerning phase masks and attempt to bridge the gap between two instrumental systems in which they are often found: the Mach-Zehnder interferometer and the coronagraph.

36 citations