AN OVERVEW OF THE KECK INTERFEROMETER NULLER

摘要

The first high dynamic range interferometry mode planned to come on line at the Keck Observatory is mid-infrared nulling interferometry. In this paper, an overview is given of the goals and experimental configuration of the Keck Interferometer Nuller (KIN). After an introduction to the science enabled by mid-infrared nulling interferometry on the Keck Interferometer's baseline, a system level overview of the experiment is provided, which includes a discussion of the optical path-length matching and stabilization approaches. This is followed by brief tours of both the nulling beam-combiner breadboard and the mid-infrared camera to be used in the experiment. The paper concludes with a discussion of the performance levels attained to date with- the mid-infrared nullers built at the Jet Propulsion Laboratory. These symmetric nullers, all based on the modified Mach-Zehnder beam-combiner configuration, have now experimentally verified the predicted dual-polarization nulling capability of a reversed beamsplitter pair arrangement. To date, the JPL nulling beamcombiners have nulled broadband thermal mid-infrared radiation to the 10~(-4) level, and monochromatic (10.6 μm CO_2 laser) radiation to the 10~(-6) level.