A universal polarimeter using liquid crystal variable retarders at the Norikura Solar Observatory
Year: 2001
Type: article
Abstract: A universal Stokes polarimeter was developed for the 25-cm coronagraph of the Norikura Solar Observatory.The polarimeter utilizes two liquid crystal variable retarders (LCVR) as the polarization modulator and a Savart plate as the polarization analyser.By controlling the voltages applied to LCVRs, modulations of the polarization states are achieved more flexibly and e$ciently in a wavelength range of 450῍1,600 nm.The polarimeter is installed at the primary focus of the coronagraph to minimize the instrumental polarization caused by optics.Two orthogonal polarization states are measured simultaneously to minimize the e#ect of guiding crrors and seeing e#ects.Combined with the coronagraph and the high resolution spectrograph at the coude focus, the polarimeter enables us not only observations of photospheric Zeeman e#ect but also various types of diagnostics of the solar atmosphere, including coronal Zeeman e#ect, Hanle e#ect, impact polarization, and Stark e#ect.
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3014005378