Master thesis and internship[BR]- Master's thesis : Optical design of an imaging static spectropolarimeter for space use[BR]- Integration Internship

Abstract

The purpose of this thesis is to perform the preliminary design of an imaging static spectropolarimeter for space use. While polarimetry and and spectrometry have been familiar tools in astronomy for a long time, the development -for space use- of instruments capable of simultaneously extracting both the spectrometric and the polarimetric information from a given light beam has lacking. A partial explanation to this lies in the historical use of moving parts in polarimeters which are highly undesired in space as they expose the instrument, and potentially the mission, to failure.

Common spectropolarimeters are also typically not able to provide the information in a spatially resolved manner without performing a step-by-step scanning of a given target or scene, a time-consuming procedure during which the state of the target will potentially change.

This design utilizes a static polarimeter that performs a spatial modulation of the polarization state into an intensity. A pinhole is placed in front of the instrument that serves the double purpose of making it an imaging system and to control the collimation that is required for the modulator. A grism is placed after the modulator to disperse the light in the direction perpendicular to the modulation direction, taking advantage of the fact that the collimation is preserved as it went through the grism. The use of a grism also allows the system to remain straight. Finally, a cylindrical lens array is used to focus the dispersed rays onto the detector plane.