New Absolute Distance Interferometric Technique

摘要

We present a new method for the measurement of the absolute distance of a remote target based on the laser diode self-mixing interferometry technique, assisted by an electronic feedback loop capable of increasing the measurement accuracy. In this method, we use an electronic feedback loop to generate a wavelength change that exactly corresponds to one single interferometric fringe. This allows to measure the target distance with a higher accuracy, in principle limited only by detection shot-noise, and not by the fringe quantization error typical of conventional fringe counting approaches. The target distance can be measured with 0.3 mm accuracy, in the 0.2-3 m range.