An AF-1 Analytical Fourier-Transform Spectrometer for a Wide Field of Applications

An AF-1 Fourier spectrometer is developed on the basis of a two-beam interferometer with a pendulum-type scanning unit, which is manufactured of a special alloy ensuring its time stability, and a stationary block of plane reflectors made of a highly stable glass. The performance characteristics of the instrument are as follows: the IR spectrum region is 400–4000 cm–1; the highest resolution is 1 cm–1; the accuracy of determining wave numbers is ±0.1 cm–1; the optical-density measurement range is 0.05–3 units; the variations of the deviation from the 100% transmission level in the entire spectral region are within ±0.5%; the rms deviation of the optical density in the range of 0.2–2.0 units is ∼1%; and the signal-to-noise ratio in the range of 2000–2100 cm–1 is at least 104 for a measurement time of 2 min and a spectral resolution of 1 cm–1.