A simple method for the compensation of the nonlinearity in the heterodyne interferometer

Eom, Tae Bong; Choi, Tae Young; Lee, Keon Hee; Choi, Hyun Seung; Lee, Sun Kyu

doi:10.1088/0957-0233/13/2/313

Cited by 77 publications

(51 citation statements)

References 9 publications

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“…The intensity of electric field from the photo detector B is as follows. The intensity 1 m of output signal as measurement at photo detector B is [5] …”

Section: Nonlinearity In Heterodyne Interferometermentioning

confidence: 99%

Robust adaptive Kalman filtering for nonlinearity compensation in laser interferometer

Shao

Lee

You

2010

2010 the 2nd International Conference on Industrial Mechatronics and Automation

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In this paper, we propose a robust adaptive Kalman filter design for the dynamic nonlinearity compensation in the heterodyne laser interferometer expressed by a state equation with the parameters uncertainty. The interferometer's measurement process is modeled to improve the displacement precision. The adaptive factor is adopted to tune the covariances of process noise and measurement noise. Through the comparison of experimental results with those obtained by a capacitance displacement sensor, it is proved that the robust adaptive Kalman filter can improve the robustness of the system and the accuracy of the displacement measurement in real time.

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“…The intensity of electric field from the photo detector B is as follows. The intensity 1 m of output signal as measurement at photo detector B is [5] …”

Section: Nonlinearity In Heterodyne Interferometermentioning

confidence: 99%

Robust adaptive Kalman filtering for nonlinearity compensation in laser interferometer

Shao

Lee

You

2010

2010 the 2nd International Conference on Industrial Mechatronics and Automation

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“…Proper alignment techniques and coatings must be used to achieve this. When aligned properly, this eliminates the periodic nonlinearity uncertainty associated with corrective techniques (e.g., [14,15]). …”

Section: Single-pass Interferometermentioning

confidence: 99%

Balanced interferometric system for stability measurements

et al. 2009

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We describe two different, double-sided interferometer designs for measuring material stability. Both designs are balanced interferometers where the only optical path difference is the sample and the reference beams are located within the interferometer. One interferometer is a double-pass design, whereas the other is a single-pass system. Based on a tolerancing analysis, the single-pass system is less susceptible to initial component misalignment and motions during experiments. This single-pass interferometer was tested with an 86 nm thin-film silver sample for both short-term repeatability and long-term stability. In 66 repeatability tests of 30 min each, the mean measured drift rate was less than 1 pm=h rms. In two long-term tests (>9 h), the mean drift rate was less than 1:1 pm=h, which shows good agreement between the short-and long-term measurements. In these experiments, the mean measured length change was 2 nm rms.

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“…The 3,296 X-ray signals that correspond to the two optical signals are obtained during the calibration. The measured nonlinear errors are sine-fitted and compensated through simple calculations (Eom et al 2001(Eom et al , 2002. Figure 6 of Lee et al (2007) shows the nonlinear errors in two cycles of the optical signals.…”

Section: The Optical Interferometermentioning

confidence: 99%

A nano-metrology system with a two-dimensional combined optical and X-ray interferometer and an atomic force microscope

Park

Lee

2009

Microsyst Technol

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A two-dimensional nano-scale measuring system utilizing a two-dimensional combined optical and X-ray interferometer (2D COXI) was developed for the standardization of measurement in the nanometer region. The system consists of a 2D COXI and an atomic force microscope (AFM). The designed, two-dimensional, flexure-stage scans and the cantilever tip probes the nanostructure of the specimen. The calibrated optical interferometers in the 2D COXI were used to measure two-dimensional nano-scale lengths. The accuracy of the optical interferometers was enhanced to enable sub-nanometer measurements. To demonstrate the nano-scale measuring system, we used it to measure the nano-scale pitches of gratings.

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A simple method for the compensation of the nonlinearity in the heterodyne interferometer

Cited by 77 publications

References 9 publications

Robust adaptive Kalman filtering for nonlinearity compensation in laser interferometer

Robust adaptive Kalman filtering for nonlinearity compensation in laser interferometer

Balanced interferometric system for stability measurements

A nano-metrology system with a two-dimensional combined optical and X-ray interferometer and an atomic force microscope

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