Stable lateral-shearing interferometer for production-line inspection of lenses

Cho, Woo-Jong; Kim, Seung-Woo

doi:10.1117/1.601142

Cited by 10 publications

(4 citation statements)

References 16 publications

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“…2 Lateral-shearing interferometer may also be regarded as another form of common-path design in which the reference wave is produced from the measurement wave with a small lateral offset by using diffraction gratings or prisms. 3 Use of a scatter-plate also enables to obtain a form of common-path configuration with high immunity to vibration. 4 Vibration influence may also be suppressed in an active way of direct feedback control incorporating adequate vibration sensing and subsequent wave front adjustment.…”

Section: Introductionmentioning

confidence: 99%

A point-diffraction interferometer with vibration-desensitizing capability

et al. 2006

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We present a new type of point-diffraction interferometer specially designed for industrial use with high immunity to external vibration encountered in the course of measurement process. The proposed interferometer uses thermallyexpanded fibers instead of conventional pinholes as the point-diffraction source to obtain a high quality reference wave with an additional advantage of relatively easy alignment of optical components. Vibration desensitization is realized through a common-path configuration that allows the influence of vibration to affect both the reference and measurement waves identically so that it is subsequently cancelled out during the interference of the two waves. A spatial phase shifter is added to capture four phase-shifted interferograms simultaneously without time delay using a single camera to avoid vibration effects. Experimental results demonstrate that the proposed interferometer is capable of providing stable measurements with a level of fringe stabilization of less than 1 nanometer in a typical workshop environment equipped with no excessive ground isolation for anti-vibration.

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Section: Introductionmentioning

confidence: 99%

A point-diffraction interferometer with vibration-desensitizing capability

et al. 2006

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“…To make the required phase shifting, many types of shearing interferometers using PZT or moving prism were developed. 3,4 But because PZT has many error sources such as the nonlinearity, hysteresis, temperature dependency etc. 3 , and the moving distance of PZT or prism giving the required phase shifting is as short as the wavelength λ, reducing the phase shifting error in the lateral shearing interferometer is always one of the major issues.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5] And with the aids of the rapid computer system, the phase shifting interferometry(PSI) is also widly used to analyze the wavefront. PSI technique needs a series of interferograms which have a series of phase differences between the reference wavefront and the object wavefront.…”

Section: Introductionmentioning

confidence: 99%

Simple lateral shearing interferometer using phase shifting interferometry technique

Song

Lee

et al. 2002

SPIE Proceedings

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In order to use phase shifting interferometry(PSI) in lateral shearing interferometer, piezoelectric transducer(PZT) is mainly used. But because PZT has many error sources and the moving distance for required phase shifting is very short, the phase shifting quantity has always considerable errors. We present a simple phase shifting technique without PZT.Moving the wedge plate parallel to the first wedge surface changes the phase difference between the original wavefront and the sheared wavefront. This method makes the shearing interferometer very simple in spite of using PSI technique.We derive the phase shifting relations originated from the moving wedge and discuss some error factors..

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“…The point-diffraction interferometer by Smartt and Steel [2] is an example which generates a reference wave from the focused measurement wave through a pinhole. The lateral shearing interferometer is a common-path interferometer, and optical pick-up lenses in a production line were tested by Cho and Kim [3]. The scatter plate interferometer is also a common-path interferometer with high immunity to external vibration [4].…”

Section: Introductionmentioning

confidence: 99%

A fiber-diffraction interferometer using a coherent fiber optic taper

Kihm¹,

Lee²

2010

Meas. Sci. Technol.

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Abstract.We present a fiber-diffraction interferometer using a coherent fiber optic taper for optical testing in an uncontrolled environment. We use a coherent fiber optic taper and a single-mode fiber having thermally-expanded core. Part of the measurement wave coming from a test target is condensed through a fiber optic taper and spatially filtered from a single-mode fiber to be reference wave. Vibration of the cavity between the target and the interferometer probe is common to both reference and measurement waves, thus the interference fringe is stabilized in an optical way. Generation of the reference wave is stable even with the target movement. Focus shift of the input measurement wave is desensitized by a coherent fiber optic taper.

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Stable lateral-shearing interferometer for production-line inspection of lenses

Cited by 10 publications

References 16 publications

A point-diffraction interferometer with vibration-desensitizing capability

A point-diffraction interferometer with vibration-desensitizing capability

Simple lateral shearing interferometer using phase shifting interferometry technique

A fiber-diffraction interferometer using a coherent fiber optic taper

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