A servo-controlled Fabry-Pérot interferometer for the FIR

Abstract The novel mechanical and electrical design of a FIR servo-controlled Fabry-Perot interferometer is described. This compact instrument is capable of scanning a gap range of >6260 μm with a resolution of 0.1 μm and at speeds in excess of 10 linear ramps sec −1 . Parallelism across the operating area of the etalon is maintained to better than 0.2 μm, even whilst scanning at full speed.