In a polarizing Fourier’ spectrometer the spectral information is contained in the interference pattern of polarization states as the function of the path difference. This is especially useful at low frequencies, where polarizing beamsplitters are much more efficient than non-polarizing ones.
The TeslaFIR spectrometer is an automated instrument which enables the measurement of spectra in the energy range from 200cm-1 down to 2cm-1. It uses a mercury arc lamp as the light source in a polarizing (Martin-Puplett) interferometer SPS-200, and detects light with a bolometer that is cooled to 0.3K by pumping on He3. The samples can be cooled down to 2.5K. The cryostat is equipped with a 17T magnet, where samples can be mounted in Faraday and Voigt configurations for measuring absorption spectra. There is a separate insert for reflection measurements.
The interferomerometer can be coupled with a dilution refrigerator, where absorption spectra can be measured of samples at 150mK in magnetic fields up to 12T.
Fourier’ spectrometer Vertex 80v (Bruker) with a Konti cold finger cryostat (5–400 K) and has spectral range 10–50 000 cm–1. It can be configured for absorption or reflectance measurements. ATR spectra can be measured in the infrared.
Toptica Terascan 85O Continuous wave Teraherts Spectroscopy Platform (0.05 – 2 THz / 1.67 – 66.7 cm-1) can be used in zero fields together with the same Konti cold finger cryostat (5–400 K).