Zero-order drift of interferograms in ultraviolet imaging spectrometer

Zero-order drift is inherently present in the interferogram of a spatially-temporally modulated ultraviolet Fourier-transform imaging spectrometer. The calculation of optical path of beam splitter in interferometric structure indicates that the zero-order drift is caused by refractive index variation in the ultraviolet wavelength range of optical adhesive and prism in the beam splitter. However, assembly misalignment of the prism may cause more serious zero-order drift, resulting in loss of the effective interference information and distortion of the spectral curve. The numerical simulation results verify that it is necessary to improve the assembly precision of the beam splitter to avoid loss of effective interference information. The measurement results show that the spectral inversion curve of the spatially-temporally modulated interferometric imaging spectrometer which contains inherent zero-order drift is consistent with the measurement result of a high-resolution spectrometer. When the beam splitter has high assembly precision, the zero-order drift does not affect the measurement accuracy of the imaging spectrometer.