Minimizing interferometer misalignment errors for measurement of subnanometer length changes

摘要

The detailed knowledge of thermal expansion and dimensional stability of low expansion materials is of growing interest and requires measurements of length changes with sub nm uncertainty. In addition to accurately defined environmental conditions the interferometer adjustment, namely the number of fringes covering the sample and also the method of autocollimation adjustment, become more important. Their influence, investigated with PTB's precision interferometer, will be discussed.