Precise interferometric length measurement using real-time fringe fitting
| Autor: | Dan Apostol, Petre Cătălin Logofătu, Bogdan Ioniţă |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Physics
Accuracy and precision Offset (computer science) business.industry Astrophysics::Instrumentation and Methods for Astrophysics Laser Horizontal plane Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials law.invention Length measurement Interferometry Optics Software law Perpendicular Electrical and Electronic Engineering business |
| Zdroj: | Optik. 122:868-871 |
| ISSN: | 0030-4026 |
| Popis: | We created a simple device for the measurement of nanoscale displacements consisting in a Twyman–Green interferometer with one mirror having a slight offset in the horizontal plane with respect to the direction perpendicular to the incoming beam and one mobile mirror, a CCD array camera that captures frames of fringes (interferograms) generated by the interferometer and a software that acquires the interferograms captured by the camera and fits the fringes in order to determine the initial spatial phase of the series of fringes and, consequently, to monitor the movement of the mobile arm of the interferometer. Because the interferograms were acquired and analyzed sequentially, the algorithm could be parallelized easily on a multiprocessor/multicore platform. The device can work in real-time in which case the maximum speed of the mobile arm of the interferometer for which we can obtain unambiguous results is 30 λ/8/s, which is, assuming a He–Ne laser as the light source, almost 2.5 μm/s. In real-time conditions, the precision and accuracy of the measurement are low. In stationary conditions, however, the precision was determined to be below 1 nm. |
| Databáze: | OpenAIRE |
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