Verification of phase measurement error sources in phase-shifting interferometry with four step phase-shifting algorithms.

The phase-shifting technique is one of the most important techniques in interferometry. The measurement accuracy of this technique is affected by several kinds of systematic and random errors like miscalibration, nonlinear response and tilt shift of the phase shifter, nonlinear recording, speckles, fringe fluctuation, etc. In this paper, a method for verification of all of these phase measurement error sources is proposed by introducing a grayscale image.

Evaluation method for the optical feedback factor and linewidth enhancement factor using phase discontinuities in self-mixing interferometry signals.

Self-mixing interferometry (SMI) is a reliable method that has been applied to measuring displacements, absolute distances, and velocities of remote targets. Evaluating the optical feedback factor and the linewidth enhancement factor is a vital step in calculating laser diode parameters and in processing SMI signals using phase unwrapping. This paper proposes an evaluation method for the optical feedback factor and the linewidth enhancement factor of arbitrary waveforms by investigating the slopes of phase discontinuity distribution in the optical feedback regime of 1<.

Study on the vibration displacement distribution of a circular ultrasonic motor stator.

In this paper is presented a theoretical consideration on the stator's displacement distribution, which is one of the most important problems in defining the structure of a circular ultrasonic motor stator. The results are compared with ones obtained utilizing a holographic interferometer, a laser vibrometer and FEM (finite element method) simulation. They are in good agreement with each other.