Structured light interferometry

Optical interferometry has made tremendous development in fundamentals and applications of light. Traditional optical interferometry using simplex plane phase light just allows one dimensional measurement, but incapable of retrieving multidimensional movement. Here, we present new structured light interferometry to achieve simultaneous determination of rotational and translational dimensionalities (magnitudes and directions) of moving objects by fully exploiting multiple degree of freedoms of structured light. Such multidimensional detectability benefits from multiple amplitude and sign distinguishable Doppler shifts of structured light by analyzing relative amplitude and phase information of Doppler signals. We experimentally demonstrate two interferometric schemes to individually retrieve both translational and rotational velocity vectors of two kinds of moving objects (small particles and bulk targets). These interferometric schemes based on structured light show remarkable function enhancement for simultaneous measurement of multidimensional motion vectors, compared with traditional interferometry, and thus may expand optical interferometry to multidimensional metrology in remote sensing, intelligent manufacturing and engineering.