The High-resolution Imaging Multiple-species Atmospheric Profiler (HiMAP) is an ultraviolet imaging spectro-polarimeter in development at the Jet Propulsion Laboratory for measuring O3 and NO2 concentrations in the troposphere from an airborne platform or satellite. In this paper: (1) the HiMAP design is illustrated and modeled using 3D polarization ray tracing calculus, (2) the dependency between the condition number of the systems polarization measurement matrix and properties of individual optical components is used as a method for tolerancing, and (3) the polarimeter capabilities of manufacturable thin film designs of polarizing and non-polarizing beam splitters is explored using numerical methods. The condition number of an optical system is calculated from a polarization ray tracing (PRT) matrix model of the polarimeter. Deviations of the condition number are calculated for non-ideal polarization elements and coatings to understand component and alignment tolerances.
Direct imaging and spectroscopy of terrestrial exoplanets requires the control of vector electromagnetic fields to approximately one part in ten to the fifth over a few milliarc second FOV to achieve the necessary 10-10 intensity contrast levels. Observations using space telescopes are necessary to achieve these levels of diffracted and scattered light control. The highly reflecting metal mirrors and their coatings needed to image these very faint exoplanets introduce polarization into the wavefront, which, in turn affects image quality and reduces exoplanet yield unless corrected. To identify and create the technologies and the electro-optical/mechanical-spacecraft systems models that will achieve these levels, NASA is currently developing two mission concepts, each with their own hardware vision. These are: The Habex, a habitable planet explorer and the LUVOIR, a Large Ultra-Violet Optical-Infrared space telescope system. This paper reports the results of polarization ray-tracing the HabEx detailed optical prescription provided by the project to the authors in the fall of 2017. Diattenuation and retardance across both the exit pupil associated with the occulting mask and the exit pupil associated with the coronagraph image plane are given as well as the corresponding Jones pupil matrices. These are calculated assuming isotropic coatings on all mirrors. Analysis and physical measurements indicates that the specification of the primary mirror for exoplanet coronagraphs will need to include a constraint on spatially varying polarization reflectivity (anisotropic coatings). The Jones exit-pupil phase terms, phi XX and phi YY just before the occulting mask differ in shape and are displaced one from the other by about 10 milli-waves. This shows that A/O, which corrects for geometric path differences, cannot completely correct for wavefront errors introduced by polarization for this particular prescription for HabEx. We suggest that these differences may be corrected by adjusting the opto-mechanical design to change angles of incidence on mirrors and corrected by adjusting the design of the dielectric coatings on the highly-reflecting mirror surfaces. Super-posing the phase of XX onto the phase of YY and then correcting using A/O will assure maximum power transmittance through the system and best contrast. These aspects require further investigation.
Low polarization, high numerical aperture microscope objectives ideal for polarization sensitive
applications are designed, fabricated, and measured. A microscope objective is designed to meet the application
requirements using Code V. Performance of typical AR coatings is examined and determined to be insufficient to
meet the polarization performance desired. Custom AR coatings are optimized using an in house polarization ray
tracing program to reduce the objectives diattenuation. The resulting microscope objectives perform about 5 times
better than our low polarization Nikon objectives.