Polarimetry

Polarization is a fundamental property of light, and measuring that polarization often yields crucial information about the source or the matter between the source and the observer, which is unobtainable otherwise. In general, polarization is created and/or modified at any location of interaction with light that involves some kind of breaking of symmetries. For instance, magnetic fields and small particle properties are easily measured by polarimetry while pure intensity measurements contain little to no information. Our group specializes in measuring polarization with very high sensitivity and/or accuracy to learn more about stellar magnetic fields, dust in planetary and exoplanetary atmospheres as well as in circumstellar disks where planets are forming. Furthermore, we develop miniature and low-cost spectropolarimeters for remote sensing of air pollution from satellites, aircraft and by citizen scientists. Our research spans from solving fundamental optics problems to developing low-cost smartphone polarimeters. Active areas of research include subtle polarization-dependent aberrations that limit our ability to detect exoplanets, novel modulation concepts that avoid moving parts and are insensitive to temperature, and polarimetric integral field units to measure the polarization as a function of wavelength for each pixel in the field of view.