Novel phase measurement technique of the heterodyne laser interferometer

Choi, Hae-Wook; Park, Kyihwan; La, Jongpil

doi:10.1063/1.2038527

Cited by 12 publications

(6 citation statements)

References 8 publications

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“…The third type of digital phase meter detects the sampled signal zero-crossing time to estimate the signal frequency or its phase [14][15][16][17][18]. Many applications, including gas spectroscopy [19], power-management systems [20], and vibration metrology [21], have been investigated with such systems.…”

Section: Introductionmentioning

confidence: 99%

“…Although some techniques have been proposed to implement fringe counting in the digital processing framework and enhance its resolution [10][11][12][13], they demand complex algorithm and hardware. The third type of digital phase meter detects the sampled signal zero-crossing time to estimate the signal frequency or phase difference [14][15][16][17][18]. Many applications, including gas spectroscopy [19], power-management systems [20], and vibration metrology [21], have been investigated with such systems.…”

Section: Introductionmentioning

confidence: 99%

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Simple digital phase-measuring algorithm for low-noise heterodyne interferometry

Kokuyama

Nozato

Ohta

et al. 2016

Meas. Sci. Technol.

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We present a digital algorithm for measuring the phase difference between two sinusoidal signals that combines the modified fringe-counting method with two-sample zero crossing to enable sequential signal processing. This technique can be applied to a phase meter for measuring dynamic phase differences with high resolution, particularly for heterodyne interferometry. The floor noise obtained from a demonstration with an electrical apparatus is 5 × 10 −8 rad/√Hz at frequencies above approximately 0.1 Hz. In addition, by applying this method to a commercial heterodyne interferometer, the floor-noise level is confirmed to be 7 × 10 −14 m/√Hz from 4 kHz to 1 MHz. We also confirm the validity of the algorithm by comparing its results with those from a standard homodyne interferometer for measuring shock-motion peak acceleration greater than 5000 m/s 2 and a 10 mm stroke.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simple digital phase-measuring algorithm for low-noise heterodyne interferometry

Kokuyama

Nozato

Ohta

et al. 2016

Meas. Sci. Technol.

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“…Most of the commercial laser interferometers are heterodyne interferometers [59][60][61], also called dual-frequency interferometers, in which the frequency difference can be generated by the Zeeman effect [62] or an acousto-optical modulator [63,64], as shown in figure 5(a). It overcomes the shortcomings of the DC drift of the single-frequency laser, and has the advantages of low noise and strong anti-interference ability.…”

Section: Interferometric Techniques For Length Measurementmentioning

confidence: 99%

A review of interferometry for geometric measurement

Yang

Zhang

2018

Meas. Sci. Technol.

124

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As high-precision measuring instruments have developed, interferometers have been widely applied in the measurement of lengths and of the shape of surfaces, with nanometer precision. The emergence of the laser is one of the revolutions that has led to a well-defined traceability route to the definition of the meter via interferometry. Another change is the ever-increasing adoption of detector arrays substituting for conventional methods of recording and analyzing interferograms. New applications have also arisen from the adoption of microscopes, optical fibers, chip-level components and diffractive optical elements, developing enhanced analogues of conventional interferometers, which have the advantages of high integration, low noise levels, and complete sets of measuring instruments with a high level of automation. Since the requirements for measurement parameters and the environment are becoming more complex, we expect that the related instruments will play a progressively significant role in the progress of advanced manufacturing processes and quality control. Multi-sensor integrated flexible measurement methods have been proposed to perform measurements with holistic, more accurate and reliable information. However, most of the proposed methods are not intelligent and are highly integrated, providing only specific solutions for given measuring tasks. In this paper, the principles, progress, prospects and development trends of interferometry are reviewed.

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“…The development of the He-Ne laser started as early as 1961. Since then it has been used in a great variety of applications such as medical lasers [1,2], laser measurements [3,4], laser holography [5] and laser spectroscopy [6] because of its low cost, long lifetime, simple structure and convenience in use. Recently, photodynamic therapy (PDT) of cancer has been given much attention [7].…”

Section: Introductionmentioning

confidence: 99%

High power He–Ne laser with flat discharge tube

Ling¹

2006

J. Phys. D: Appl. Phys.

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A high-power He–Ne laser with a flat discharge tube has been realized. Its output power can be enhanced by increasing the transverse size of the discharge tube. This high-power flat He–Ne laser tube of 1.4 m discharge length can achieve above 180 mW of output power at a wavelength of 0.6328 µm. Its optimum discharge parameters and the gain characteristics are investigated experimentally. The experiments indicate that the optimum current increases with decreasing total gas pressure. But the increase in the optimum current is almost independent of the gas mixture ratio. The increase in the gain coefficient at the axis of the discharge tube with discharge current is not obvious. The boost in laser output power is mainly caused by the expansion of the lasing gain region. To achieve the higher output power, four of the laser tubes mentioned above are placed into one laser box. The laser beams are coupled into a quartz optic fibre and the output power from the end of the optic fibre can reach above 480 mW. This high-power He–Ne laser has been used in a clinical application, photodynamic therapy (PDT) of cancer, and its effective rate is above 90% in 183 clinical cases. The structure, characteristics and applications of this high-power flat He–Ne laser are introduced and discussed in this paper.

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Novel phase measurement technique of the heterodyne laser interferometer

Cited by 12 publications

References 8 publications

Simple digital phase-measuring algorithm for low-noise heterodyne interferometry

Simple digital phase-measuring algorithm for low-noise heterodyne interferometry

A review of interferometry for geometric measurement

High power He–Ne laser with flat discharge tube

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