FSP - Fast Solar Polarimeter

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Many open questions in solar physics demand the acquisition of spectropolarimetric measurements of solar light with challenging requirements in terms of spatial, spectral and temporal resolution, and polarimetric sensitivity. The two major impediments to meet these requirements from the ground are the reduction of spatial resolution and the spurious polarimetric signals produced by the atmospheric seeing (SIC). Standard numerical techniques used to correct for seeing induced image aberrations require short exposure times (< 10 ms). In addition, a fundamental solution to reduce SIC is to increase the modulation frequency of the polarimeter beyond the values defined by the typical seeing coherence time (> 100 Hz). The two aforementioned properties can be met by a high-cadence polarimeter. This thesis describes The development of such a polarimeter and presents the results obtained with a specific instrument, namely, the prototype of the Fast Solar Polarimeter (FSP). FSP is based on a high-cadence (up to 800 fps) camera and a polarization modulator that employs ferro-electric liquid crystals. The camera is custom-made around a frame-transfer, back-illuminated pn-type CCD sensor, that has high sensitivity and provides almost 100% duty circle. The FSP instrumental concept was validated in five observing campaigns carried out between 2013 and 2015, at the 68-cm German Vacuum Tower Telescope located in El Teide observatory on Tenerife.