Design of a Full-Stokes Polarimeter for VLT/X-shooter
arXiv:1207.2965 · doi:10.1117/12.926163
Abstract
X-shooter is one of the most popular instruments at the VLT, offering instantaneous spectroscopy from 300 to 2500 nm. We present the design of a single polarimetric unit at the polarization-free Cassegrain focus that serves all three spectrograph arms of X-shooter. It consists of a calcite Savart plate as a polarizing beam-splitter and a rotatable crystal retarder stack as a "polychromatic modulator". Since even "superachromatic" wave plates have a wavelength range that is too limited for X-shooter, this novel modulator is designed to offer close-to-optimal polarimetric efficiencies for all Stokes parameters at all wavelengths. We analyze the modulator design in terms of its polarimetric performance, its temperature sensitivity, and its polarized fringes. Furthermore, we present the optical design of the polarimetric unit. The X-shooter polarimeter will furnish a myriad of science cases: from measuring stellar magnetic fields (e.g., Ap stars, white dwarfs, massive stars) to determining asymmetric structures around young stars and in supernova explosions.
Proc. SPIE 8446-76
References in corpus (9)
- Spectropolarimetry of Supernovae
- Large-scale magnetic topologies of early M dwarfs
- Ten per cent polarized optical emission from GRB 090102
- Magnetic field measurements and their uncertainties: the FORS1 legacy
- Evolution of the polarization of the optical afterglow of the gamma-ray burst GRB 030329
- GRB 091208B: First Detection of the Optical Polarization in Early Forward Shock Emission of a Gamma-Ray Burst Afterglow
- Wavelength-Diverse Polarization Modulators for Stokes Polarimetry
- Polarimetry of the transient relativistic jet of GRB 110328 / Swift J164449.3+573451
- Linear Spectropolarimetry and the Circumstellar Media of Young and Massive Stars
Cited by in corpus (8)
- The Polstar High Resolution Spectropolarimetry MIDEX Mission
- Design and Performance Analysis of a Highly Efficient Polychromatic Full-Stokes Polarization Modulator for the CRISP Imaging Spectrometer
- Calibrating and Stabilizing Spectropolarimeters with Charge Shuffling and Daytime Sky Measurements
- Daytime Sky Polarization Calibration Limitations
- Polarization Modeling and Predictions for DKIST Part 5: Impacts of enhanced mirror and dichroic coatings on system polarization calibration
- Polarization Modeling and Predictions for DKIST Part 4: Calibration Accuracy Over Field of View, Retardance Spatial Uniformity And Achromat Design Sensitivity
- Full Stokes polarimetry using Dual-Frequency Liquid Crystals
- Polarization Modeling and Predictions for DKIST Part 1: Telescope and example instrument configurations