Sub-Nanometer Heterodyne Interferometry and Its Application in Dilatometry and Industrial Metrology

In this article, we present the current status of our high-sensitivity compact heterodyne interferometer and highlight its application in high-accuracy dilatometry and industrial surface metrology. The linear coefficient of thermal expansion (CTE) of dimensionally highly stable carbon-fiber reinforced plastic (CFRP) was measured with 10−7 K−1 accuracy. A very compact and quasi-monolithic interferometer setup is currently developed utilizing ultra-low expansion glass material. We present first investigations on the corresponding integration technologies, hydroxide-catalysis bonding and adhesive bonding. For high resolution 3-D profilometry and surface property measurements, a low-noise actuator will be implemented in the interferometer, which enables a scan of the measurement beam over the surface under investigation.