Real-fringe DASH interferometer for upper atmospheric wind and temperature observation: concept and simulation

Doppler asymmetric spatial heterodyne spectroscopy (DASH) is a new technology for measuring upper atmospheric winds by observing the Doppler shift of atmospheric emission lines from a satellite using a limb viewing geometry. The real-fringe DASH interferometer is a modification of conventional DASH interferometer; it keeps the advantages of the conventional one. Moreover, this interferometer will not need exit optics to image the superposed fringes onto the detector; it will be more compact and lightweight, making it suitable for space-based platforms. We describe the concept of the new interferometer and present the exact expression of spatial frequency and phase of the interferogram. We also describe design and simulation of a real-fringe DASH interferometer for observation of the O [1D] 630nm emission. The simulation results agree with the theory.