Advances in material displacement sensing by means of novel laser feedback techniques

We present the performance characteristics of a novel laser feedback technique for displacement measurement of moving materials. The approach has been shown to be robust at high temperatures and offer the prospect of remote sensing in harsh environments. The sensor head basically consists of two single laser feedback interferometers which are asymmetrically arranged with a stable intermediate angle. The measurement results indicate that the method offers advantages in ease of alignment, sensitivity and robustness over conventional laser Doppler techniques.