Spectral information acquisition enabled by a multi-aperture imaging system with high spatial resolution capability

Abstract

Multi-aperture optical telescopes have been extensively researched because they can achieve a comparable high spatial resolution as a single large filled aperture. However, the spectral information of the objects is also essential and can effectively reflect their physical and chemical characteristics. Applying the Fourier transform imaging spectroscopy (FTIS) technique, the multi-aperture imaging system can also obtain spectral information by scanning the optical path delay (OPD) between sub-apertures. Here, we propose a scheme to appropriately set up the optical path control module of the multi-aperture system, enabling the acquisition of both high spatial resolution images and spectral information within a single multi-aperture imaging system. High spatial resolution information is obtained when the sub-apertures are in phase, and spectral information is obtained when OPDs between sub-apertures are scanned. Detailed simulations have been conducted for point-like sources and extended objects. It indicates that the system can obtain non-overlapping spectral information when applying an appropriate delay rate for each sub-aperture. Moreover, it also shows that some redundant low-frequency information is resolved from the extended objects, which originates from the image degradation caused by the separated sub-apertures of the system. The FTIS experiments performed with a multi-aperture imaging system have been carried out, demonstrating the input spectral information can be recovered precisely. The proposed scheme enables the multi-aperture imaging system to obtain high spatial resolution images and spectral information, expanding its functionality while controlling its cost and complexity.