Using the y, y-bar diagram to control stray light noise in IR systems

Abstract

Stray light in an (infrared) optical system is the radiation that is incident on the detector, but does not originate from the conjugate object point. Cool stops are usually placed at strategic locations to decrease the amount of stray light noise incident into the detector plane. Contrary to the present practice, the stray light control is improved when the telescope and instrument subsystems are analyzed as a single optical system. We describe an approach to the stray light management and control that may be performed simultaneously with the first order optical system design using the y, y-bar diagram.