We describe an extension of the active homodyne technique to produce stabilised, p/2 radian phase steps in a full-field interferometer. We have implemented the technique in a single mode fibre optic fringe-projector for shape measurement. The interference intensity (and hence phase) is maintained constant by feedback control to a phase modulator in one of the fibre arms. The feedback system has been modified to produce p/2 radian phase steps in the projected fringes. The phase stability and accuracy of each step was measured to be 17 milliradians in a 50 Hz bandwidth. The technique can be used to produce stabilised phase-stepped images in any fibre or bulk optic interferometer where active homodyne feedback control can be implemented.
|Number of pages||7|
|Journal||Proceedings of SPIE - the International Society for Optical Engineering|
|Publication status||Published - 2000|
|Event||Optical Diagnostics for Industrial Applications - Glasgow, UK|
Duration: 22 May 2000 → 24 May 2000