Novel methods used to test large flat mirrors

Abstract

The most accurate 2m-diameter flat mirror in the world was made using new surface-measurement techniques in concert with software that simulates polishing processes.

The Removal of Artificially Generated Polarization in SHARP Maps

“…Current work in this field is being carried out at the Caltech Submillimeter Observatory (CSO) using the Submillimeter High Angular Resolution Polarimeter (SHARP). SHARP is a fore-optics module designed to be used in conjunction with the SHARC-II camera to form a highly sensitive, dual-wavelength (350-µm and 450-µm), polarimeter (Novak et al 2004;Li et al 2006). SHARC-II employs a 12 × 32 pixel bolometer array that is optically "split" by SHARP into three zones: two 12 × 12 pixel regions that record orthogonal states of linear polarization (which are labeled "H" and "V" for horizontal and vertical, respectively), and a 12 × 8 pixel central zone that is not used with SHARP.…”

“…Consider the radiation beam that is incident to the H and V sub-arrays. This radiation beam originates from a single patch of sky that is subsequently "split" into two components; a horizontally polarized component and a vertically polarized component (Novak et al 2004). As the name sake would suggest, the optical path of SHARP is designed such that the horizontally polarized component is incident on the "H" sub-array while the vertically polarized component is incident on the "V" sub-array.…”