Infrared Two-Wavelength Interferometry for Measuring Long Length

Matsumoto, Hirokazu; Seino, Shoichi; Hoshi, T.

doi:10.1016/s0007-8506(07)63336-8

Cited by 6 publications

(3 citation statements)

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“…Equation (8) shows that φ 1 repeats at every λ 1 /2 target displacement, while φ 2 repeats at every λ 2 /2 target displacement. For the direct acquisition of φ s = φ 2 − φ 1 which repeats at every λ s /2 target displacement, the heterodyne signal I (t) is self-multiplied by an electronic mixer or multiplier.…”

Section: Superheterodyne Detection Of φ S and Heterodyne Separation Of φmentioning

confidence: 99%

“…There were several methods for real-time phase measurement of the synthetic wavelength. One of them was to detect the phase of the synthetic wavelength in terms of the fringe contrast [7,8]. The fringe contrast was obtained by modulating the reference mirror mechanically.…”

Section: Introductionmentioning

confidence: 99%

“…The distance resolution obtained by using the synthetic wavelength is λ s /λ 1 times lower than that obtained by using the wavelength λ 1 , assuming that the phase resolutions of λ 1 and λ s are the same. The use of the phase coupling of λ s and λ 1 , (φ s , φ 1 ), allows high-resolution measurement with an expansive range [8,10]. de Groot demonstrated theoretically that the expanded range was wider than λ s /2 by precise measurement of φ s and φ 1 [10].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Real-time and high-resolution absolute-distance measurement using a two-wavelength superheterodyne interferometer

Yokoyama¹,

Ohnishi

Iwasaki³

et al. 1999

Meas. Sci. Technol.

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We present here a new method for real-time absolute-distance measurement. It is based on a two-wavelength superheterodyne interferometer. It is performed by simultaneous measurement of its synthetic wavelength and one of two wavelengths. The phase of one of two wavelengths is electrically separated from the synthetic one, thus maintaining the resolution of a one-wavelength heterodyne interferometer. Two He-Ne lasers operating at 1 = 633 nm and 2 = 612 nm are incorporated into the measuring system, as two wavelength sources, resulting in the synthetic wavelength of s = 18.4 µm. Thus, the proposed system has a range of 9.2 µm with nanometre resolution.

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Section: Superheterodyne Detection Of φ S and Heterodyne Separation Of φmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%