A new three degrees-of-freedom motion sensor based on laser-self-mixing with pigtailed sources

Real time simultaneous measurement by remote laser source of long range longitudinal displacement and small angle wobbling of a sliding target is demonstrated. The compact self-aligned laser-self-mixing interferometer achieves 0.8 µm axial resolution over 1 m linear and 17 µrad of pitch and yaw resolution over 2 mrad angular ranges, respectively.