Photoelastic microellipsometer: a new tool for high-resolution force vector measurements

We are reporting about a novel ellipsometric measurement procedure which enables us to detect forces and force- related sizes at high resolution by use of the laserinternal photoelastic effect. The measurement procedure is based on the intracavity transmission ellipsometry developed by us. Relative retardation (Delta) and orientation of the main axis p of the component under test can be concluded from the polarization state and from the beat frequency of the orthogonally polarized modes of an active laser. Our measurements of weight forces show a very good linearity in a measurement range of seven decades. The Nd:YAG-laser technology enables us to develop very small sensors at high accuracy.