Optical interferometry might open the way to a new generation of space optical telescopes. Future devices must be more compact, lightweight, and power-efficient than the current ones, with a comparable or superior optical performance. An interesting and novel solution to fulfill these requirements is offered by the SPIDER (Segmented Planar Imaging Detector for Electro-optical Reconnaissance) concept. It proposes to replace the bulky components of current devices by a planar array of lenslets sending the light received from a distant object onto an array of micro-interferometers. This array, which is embedded in photonic integrated circuits, images the brightness distribution of the object by aperture synthesis. In their paper, Tiehui Su and coworkers report a prototype supporting the feasibility of SPIDER. A few-centimeter-sized photonic circuit containing 30 micro-interferometers analyzes narrowband near-infrared light incoming through two pairs of lenslets with different few-millimeter interlens distances. It allows the observation of simple objects (point source and slit with variable micrometer scale width) located at more than one meter from the lenslets. These findings appeal to the development of more complete devices, which will include a broader array of lenslets and interferometers for the imaging of complex objects with a higher resolution.
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