In-lab high-resolution midinfrared up-conversion stellar interferometer based on a synthetic long baseline

Detecting midinfrared (MIR) radiation has significant astronomical applications, although limited by unsatisfactory MIR detectors. Here we reported on the realization of a MIR up-conversion interferometer based on synthetic long base-line in the laboratory. The experimental system consisted of an interferometer and subsequent up-conversion detection part of midinfrared signal, which streamlined the structure and enhanced the reliability of the system. By using a tungsten filament lamp as an imitated star, we not only achieved the single target angle resolution of $1.10\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}\text{ }\text{ }\mathrm{rad}$, but also obtained the field angle resolution of $3.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}\text{ }\text{ }\mathrm{rad}$ of double star targets. The angular resolution is in inverse proportion to the length of baseline. The maximum length of simulated baseline in the laboratory is about 3 cm. In a Keck interferometer liked program, the base line can reach up to 85 m leading to a corresponding angular resolution of $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}\text{ }\text{ }\mathrm{rad}$ (about 1.8 mas). The study will offer potential benefits in extending the usage of midinfrared light in astronomical exploration.