Simplified Achromatic Nulling Beam Combiner

The figure schematically depicts a proposed achromatic nulling beam combiner. This instrument is intended for use in astronomy - principally, for attenuating light from stars or other bright sources in order to enable detection of fainter objects that lie near the bright sources. In comparison with a prior nulling beam combiner, the proposed instrument would be simpler, made of fewer parts, easier to use, and less sensitive to the details of optical coatings. The proposed design provides for rigorous symmetry of the optical train. Moreover, the simplified design involves a relatively compact, mostly planar, configuration based entirely on flat optics, with fewer reflections than in previous designs. Because of its high degree of symmetry, the instrument would be inherently achromatic (broad-band) and capable of processing dual polarization light.