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Proceedings Paper

Dynamic holographic interferometry with matrix LC modulator
Author(s): S. A. Pulkin; V. Yu. Venediktov; V. Ivanov; V. I. Korotkov; I. M. Pasechnik; A. A. Sevrygin; M. A. Solov'ev
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Paper Abstract

The method of holographic intereferometry with increased sensitivity was applied for measurements of height of nanosteps (from 10 nm and higher) with standard uncertainty about 0.5 nm. The initial microinterferogram with fringes of equal width was obtained in Michelson micro-interferometer with nano-step sample in one of legs. This interferogram was registered by CCD–camera and the digital interference pattern was reproduced on matrix phase modulator with spatial resolution 30 lines/mm. The matrix phase modulator was placed at the output of the two-beam Mach-Zehnder interferometer and illuminated by two plane laser beams. These two beams diffracted on phase modulator, were focused and spatially filtered by the pinholes in (+ 1-st ) and (– 1-st ) orders of diffraction. The second digital interferogram with twofold increase of sensitivity was obtained on CCD–camera and so on. The increase of sensitivity was obtained due to the interference of waves with complex conjugated phases. One can obtain the interference of higher orders too if working with the nonlinear interferogram. It is possible to obtain any carrier fringe space frequency by using of two plane waves in the interferometer. The increase of sensitivity may be obtained in research of flatness less than λ/100, and topography of surfaces with height difference less than few nanometers as well.

Paper Details

Date Published: 26 November 2012
PDF: 6 pages
Proc. SPIE 8556, Holography, Diffractive Optics, and Applications V, 85560U (26 November 2012); doi: 10.1117/12.999679
Show Author Affiliations
S. A. Pulkin, Saint Petersburg State Univ. (Russian Federation)
V. Yu. Venediktov, Saint Petersburg State Univ. (Russian Federation)
Saint-Petersburg State Electrotechnical Institute (Russian Federation)
Vavilov State Optical Institute (Russian Federation)
V. Ivanov, Saint Petersburg State Univ. (Russian Federation)
V. I. Korotkov, Saint Petersburg State Univ. (Russian Federation)
I. M. Pasechnik, Saint Petersburg State Univ. (Russian Federation)
A. A. Sevrygin, Saint Petersburg State Electrotechnical Univ. (Russian Federation)
M. A. Solov'ev, Vavilov State Optical Institute (Russian Federation)


Published in SPIE Proceedings Vol. 8556:
Holography, Diffractive Optics, and Applications V
Yunlong Sheng; Chongxiu Yu; Linsen Chen, Editor(s)

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