Prototype characterization and future development of the Fast Solar Polarimeter

IGLESIAS, FRANCISCO A.; FELLER, ALEX; SOLANKI, S.K.; F. ZEUNER

Lanzarote

Conferencia; SOLARNET IV; 2017

SOLARNET, European Union

Due to the differential and non-simultaneous nature of temporally-modulated polarization measurements, the spurious signals and image aberrations induced by atmospheric seeing or instrument jitter can easily counterbalance the benefits of ground-based observatories. To tackle the above-named issues we are developing the Fast Solar Polarimeter (FSP), which aims for high-spatial-resolution and high-sensitivity spectropolarimetric measurements in the 390 to 860 nm spectral range by combining fast modulation frequency with high frame rate. The FSP prototype is based on a high sensitivity (QE>80%), low-noise (~3.6 e-rms), high frame-rate (400 fps) pnCCD camera and ferroelectric liquid crystals. The fast polarization modulation (100 full-Stokes sets per second) and high duty cycle (>98%), have the double benefit of reducing seeing induced crosstalk and improving the final spatial resolution by providing an optimal regime for the application of post-facto image reconstruction techniques. In this talk we describe the characterization of the FSP prototype and the first measurements acquired from 2013 to 2015 at the VTT. We also present the status and future plans for the second version of the instrument based on a larger 1k x 1k pnCCD and a dual-beam polarimetric configuration.