Shearing Interferometry Papers
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James C. Wyant
Optics Communications , Vol. 19, page 120, October 1976
A simple law interferometric technique for measuring the modulation transfer function
of an optical system is described. |
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D. A. Thomas and J. C. Wyant
Optical Engineering , Vol. 15, page
477, September-October 1976
The use of dichromated gelatin for holographically
recording the component single frequency gratings of a high efficiency
lateral shear interferometer is described. Interferograms obtained
using a grating lateral shear interferometer simultaneously having a
diffraction efficiency of 30% in each of two shearing interferograms are
presented. |
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J. C. Wyant
APPLIED OPTICS, Vol. 14, page 2622, November 1975
An analysis is performed to determine the accuracy with which an ac heterodyne lateral
shear interferometer can measure wavefront aberrations if a white light extended source is
used with the interferometer, and shot noise is the predominate noise source. The analysis
shows that for uniform circular or square sources larger than a derived minimum size, the
wavefront measurement accuracy depends only upon the radiance of the source and not upon
the angular subtense of the source. For a 1-msec integration time, a 25-cm2
collecting area, and a source radiance of 10 W/m2-sr the rms wavefront error is
approximately 1/30 wave, assuming the signal is shot noise limited. It is shown that for
both uniform circular and square sources an optimum shear distance is approximately 1/2
the aperture diameter required to resolve the light source. Comments are made on the
optimum shear for nonuniform radiance distributions.
URL:
http://www.opticsinfobase.org/abstract.cfm?URI=ao-14-11-2622 |
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J. C. Wyant and F. D. Smith
APPLIED OPTICS, Vol. 14, page 1607, July 1975
The use of a lateral shear interferometer in measuring the power variation of
ophthalmic lenses is described and demonstrated. It is shown that an appropriate lateral
shear interferometer directly measures the power variation of an ophthalmic lens. If the
ophthalmic lens has a toric surface, the power for each axis can be measured separately.
Individual surfaces can be tested, as well as the whole lens or the different segments of
a multifocal lens. The sensitivity of the test can be selected by varying the amount of
lateral shear. Because of the demonstrated simple relationship between fringe spacing and
dioptric power, qualitative examination of the fringes has proved a useful adjunct to
conventional quality control methods. URL:
http://www.opticsinfobase.org/abstract.cfm?URI=ao-14-7-1607 |
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J. C. Wyant
APPLIED OPTICS, Vol. 14, page 1619, July 1975
The use of lateral shear interferometers for measuring the optical transfer function of
an optical system for a white light source is investigated. It is shown that grating
lateral shear interferometers fulfill the requirements necessary to perform measurements
of both the optical transfer function and the optical coherence function for a white light
source. Several possible grating lateral shear interferometers are described.
URL:
http://www.opticsinfobase.org/abstract.cfm?URI=ao-14-7-1613 |
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M. P. Rimmer and J. C. Wyant
APPLIED OPTICS, Vol. 14, page 142, January 1975
A variable shear lateral shearing interferometer consisting of two holographically
produced crossed diffraction gratings is used to test nonrotationally symmetric wavefronts
having aberrations greater than 100 wavelengths and slope variations of more than 400
wavelengths/diameter. Comparisons are made with results of Twyman-Green interferometric
tests for wavefront aberrations of up to thirty wavelengths. The results indicate that
small wavefront aberrations can be measured as accurately with the lateral-shear
interferometer as with the Twyman-Green interferometer and that aberrations that cannot be
measured at all with a Twyman-Green interferometer can be measured to about 1% accuracy or
better. URL:
http://www.opticsinfobase.org/abstract.cfm?URI=ao-14-1-142 |
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P. Hariharan, W.H. Steel, and J. C. Wyant
Optics Communications, Vol. 11, page 317, July 1974
A modified Ronchi interferometer using two identical gratings is described. This
instrument is very suitable for the measurement of small, zonal aberrations, since the
shear can be changed continuously by rotating one grating with respect to the other, while
the direction and magnitude of the tilt between the sheared wavefronts can be varied by
adjusting the distances of the two gratings from the center of the Gaussian sphere. |
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J. F. Ebersole and J. C. Wyant
APPLIED OPTICS, Vol. 13, page
1004, May 1974
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J. C. Wyant
APPLIED OPTICS, Vol. 13, page 200, January 1974
A grating lateral shear interferometer is described that can be used with a white light
source. The use of the interferometer with certain types of extended sources is also
demonstrated. URL:
http://www.opticsinfobase.org/abstract.cfm?URI=ao-13-1-200 |
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J. C. Wyant
APPLIED OPTICS, Vol. 12, page 2057, September,
1973
A simple grating lateral shear interferometer is described that can be made to give
simultaneously two interferograms having shear in two orthogonal directions. The shear for
the two orthogonal directions is produced in one plane by one double frequency crossed
diffraction grating that can easily be produced holographically. Translating the grating
sideways causes the irradiance of the interferogram to vary sinusoidally with time
enabling the interferometer to be used with real-time heterodyne phase detection.
URL:
http://www.opticsinfobase.org/abstract.cfm?URI=ao-12-9-2057 |
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