Abstract: The study named Accurate Infrared Magnetic Field Measurements of the Sun (AIMS) is placed in platform D of the
Lenghu astronomical observation base in Mangya City, Haixi Prefecture, Qinghai province. By utilising the infrared Fourier transform spectrometer to obtain the Mg I spectrum of the Sun near 12.32 μm, AIMS has successfully achieved the direct measurement of the solar magnetic field. This infrared Fourier transform spectrometer features a spectral resolution of 0.004 cm-1 and a 128-element detection field of view. It has overcome key technical challenges, including the ultra-large optical path difference interferometer technology and infrared cryogenic imaging technology, and a 128-element high-performance infrared detector has been developed. Precise optical axis alignment with the telescope has been accomplished at an altitude of 4 000 m. This instrument is the world’s
first multi-pixel imaging infrared Fourier transform spectrometer with ultra-high spectral resolution dedicated to solar magnetic field measurement. This paper provides a brief introduction to the working principle, system composition, technical characteristics and scientific applications of this infrared Fourier transform spectrometer.