Phase measurement of various commercial heterodyne He–Ne-laser interferometers with stability in the picometer regime

We compare a number of different methods for fitting an ellipse to a static set of measured data points, specifically considering their suitability for interferometric application. We suggest an improved distance approximation for least-square geometric fitting and alternative normalizations for linear algebraic fitting. Of the methods considered, an algebraic fit using a data-dependent normalization has both the least bias in phase and amplitude estimation and the greatest robustness against uneven distribution of data.

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“…For comparison, the European Metrology Research Programme-funded project NANOTRACE [16,17] is aiming Fig. 4.…”

Section: Numerical Comparisonsmentioning

confidence: 99%

Ellipse fitting for interferometry Part 1: static methods

Collett

Tee

2014

J. Opt. Soc. Am. A

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“…It is worthwhile to note that the resolution as well as the rate of signal processing play a crucial role in determining the accuracy and sensitivity of the device. Further, it could be safely asserted that sub-nanometer sensitivity and resolution could be achieved using this technique through deployment of phase meters which are capable of resolving signals down to a few picometers [23,24].…”

Section: Resultsmentioning

confidence: 99%

Multiple reflection assisted Laser Doppler Vibrometer setup for high resolution displacement measurement

Pachisia

Tiwari

Das

2020

Optics Communications

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Non-intrusive displacement measurement technique has a distinct edge over displacement sensors working in contact mode. Laser Doppler Vibrometry based schemes (LDV) offer such an advantage. However, the measurements are limited up to λ/4, where λ is the wavelength of optical source. An experimental design of high resolution non-intrusive displacement sensor working on the principle of basic LDV is being presented here. Resolution enhancement has been achieved through phase multiplication using multiple reflections within a high-Q cavity created by a vibrating surface and a high reflection mirror kept parallel to each other. Displacement of 72 nm has been measured with an error range of ±14 nm through direct counting of characteristic peaks in "half cycle" of the interferogram. The experimental design offers a straightforward route to measure displacement and the measurement resolution is mainly limited by the reflectivity and physical dimension of moving source.

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“…There are three general phase measurement techniques: 1) phase-locked loop [19], [20]; 2) single-bin discrete Fourier transform (SBDFT) [21], [22]; and 3) time interval analysis [11], [19]. Fig.…”

Section: Heterodyne Interferometry Signal Processingmentioning

confidence: 99%

Dynamic Doppler Frequency Shift Errors: Measurement, Characterization, and Compensation

Wang

Ellis

2015

IEEE Trans. Instrum. Meas.

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Positioning calibration under dynamic conditions is becoming increasingly of interest for high precision fields, such as additive manufacturing and semiconductor lithography. Heterodyne interferometry is often used to calibrate a stage's position because interferometry has a high dynamic range and direct traceability to the meter. When using heterodyne interferometry, filtering is routinely performed to process and determine the measured phase change, which is proportional to the displacement from one target location to another. The filtering in the signal processing introduces a phase delay dependent on the detection frequency, which leads to displacement errors when target velocity is non-constant as is the case in dynamic calibrations. This paper presents a phase delay compensation method by measuring instantaneous detection frequency and solving for the corresponding phase delay in a field-programmable gate array (FPGA) in real time. The FPGA hardware-in-the-loop simulation shows that this method can significantly decrease the displacement error from ±100's nm to ±3 nm in dynamic cases and it will still keep subnanometer resolution for quasi-static calibrations.Index Terms-Displacement measurement, dynamic response, field-programmable gate arrays (FPGAs), interferometry, phase measurement.

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Phase measurement of various commercial heterodyne He–Ne-laser interferometers with stability in the picometer regime

Cited by 48 publications

References 17 publications

Ellipse fitting for interferometry Part 1: static methods

Ellipse fitting for interferometry Part 1: static methods

Multiple reflection assisted Laser Doppler Vibrometer setup for high resolution displacement measurement

Dynamic Doppler Frequency Shift Errors: Measurement, Characterization, and Compensation

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