The invention relates to a compact differential
interferometry imaging
spectrograph and an imaging method thereof. The
spectrograph comprises a telescoping
system, a filter, a low-chromatic-dispersionmodule, a high-chromatic-dispersion module, a polarization analyzer and a
detector, wherein the telescoping
system, the filter, the low-chromatic-dispersion module, the high-chromatic-dispersion module, the polarization analyzer and the
detector are arranged along a light path; the low-chromatic-dispersion module and the high-chromatic-dispersion module independently comprise a polarizing
beam splitting prism, a 1 / 4 wave plate, a view field expanding
prism, a
blazed grating, a 1 / 4 wave plate, a view field expanding
prism and a
blazed grating, wherein the 1 / 4 wave plate, the view field expanding prism and the
blazed grating are arranged in a transmission light path of the polarizing
beam splitting prism in sequence, and the 1 / 4 wave plate, the view field expanding prism and the blazed
grating are arranged in the reflecting light path of the polarizing
beam splitting prism in sequence; the telescoping
system is used for collecting the spectral
radiance of an observation target; the filter is used for filtering the collected spectral
radiance of the observation target; the low-chromatic-dispersion module is used for carrying out light splitting on filtered rays; the high-chromatic-dispersion module is used for gathering and emitting the rays; the polarization analyzer is used for carrying out beam combination on emergent light; and the
detector is used for receiving an interference image emitted from the polarization analyzer and carrying out imaging on the spectral
radiance collected by the telescoping system. The
spectrograph is applied to
atmospheric composition detection,and atmospheric compositions can be obtained through obtained spectrum information.