Designed for atmospheric pollution monitoring, a breadboard model of a new Michelson interferometer has been developed. It utilizes a nutating retroreflector to generate alterations in the geometrical and optical paths. The forward–backward stop–and–go movement of a reflecting element of conventional Michelson interferometers is thus replaced by a continuous rotation. At this state the instrument employs a 6.3-cm(2.5-in.) diam rotating retroreflector, a ZnSe beam splitter, and a HgCdTe detector at liquid nitrogen temperature, sensitive in the 8–14-μm band. It allows spectral resolutions of up to 2 cm^−1. The device is linked via an analog digital interface to a desktop computer which performs interferometer control, data acquisition, Fourier transform, and display of the spectra.