Determination and correction of quadrature fringe measurement errors in interferometers

Abstract

The precision and accuracy of interferometers using quadrature fringe detection are often limited not by the interferometer itself but by the detector system. There are three typical errors: unequal gain in the two channels; quadrature phase shift error; and zero offsets. This paper describes a simple method for determining the quadrature errors from experimental data obtained in the interferometer and correcting for them. A numerical example demonstrating the significant improvement in the precision of interferometer data is given.

Single beam interferometric angle measurement

“…5 we also plot the contrasts C 1 and C 2 in the (C 1 , C 2 ) plane to show that they lay on a circle. In fact, the measurement lays on a tilted ellipse, because of the imperfections in the orientation of the beam displacers and quarter wave plate, but this small deviation from the C max radius circle can easily be corrected [13]. Anyway, as shown by Fig.…”

Optical Interference Signal Processing in Precision Dimension Measurement

“…However, because of the imperfect design and manufacture of measurement system, the environmental disturbance and the system noise, the signals often have some errors, such as the nonorthogonality, the non-equality of amplitude, the drift of DC signals, and so on (Heydemann, 1981), which have very serious influence on the precision of the fringe subdivision. The typical orthogonal signals with errors are shown as follows:…”

“…(Heydemann, 1981) proposes a universal method to compensate the errors. From Eqs.33, another equation is obtained as follows:…”

“…From Eqs.37, u 1 and u 2 are obtained as follows: (Heydemann, 1981) sets up a complete method for the error compensation. This method needs at least a period of signals for the calculation of the error factors.…”

A Planar Laser Diffraction Encoder in Littrow Configuration for 2D Nanometric Positioning

“…In classical orthogonal waveforms there are three major error sources. As described by Heydemann [11], these are:…”