Title :
Beam-astigmatism in laser interferometry
Author :
Bergamin, Angelo ; Cavagnero, Giovanni ; Cordiali, Laura ; Mana, Giovanni
Author_Institution :
CNR, Torino, Italy
fDate :
4/1/1997 12:00:00 AM
Abstract :
We have developed a null laser interferometer capable of picometer resolution in fringe division for the measurement of the silicon (220) lattice spacing by X-ray interferometry. With a view to achieving 10-9 measurement uncertainty, we have given special attention to the effects of diffraction. An analysis of the measurements which has brought to light wavefront astigmatism, the effect of which had so far been overlooked, is presented. This article shows how astigmatism affects measurements, describes how we determine beam parameters, and compares theoretical and experimental results
Keywords :
X-ray crystallography; aberrations; displacement measurement; electromagnetic wave interferometers; electromagnetic wave interferometry; laser beams; light diffraction; light interferometers; measurement errors; silicon; Si; X-ray interferometry; beam parameters; beam-astigmatism; diffraction effects; fringe division; laser interferometry; measurement uncertainty; null laser interferometer; picometer resolution; silicon (220) lattice spacing; wavefront astigmatism; Interference; Laser beams; Lattices; Optical diffraction; Optical interferometry; Optical modulation; Optical sensors; Pattern analysis; Silicon; X-ray lasers;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
