The Hertz/VPM polarimeter: design and first light observations

Area of Science:

• Astronomy and Astrophysics
• Optical Engineering
• Instrumentation

Background:

• Submillimeter polarimetry is crucial for studying cosmic magnetic fields.
• Traditional polarization modulators often rely on mechanical rotation, which can be complex and introduce limitations.
• The development of new modulation techniques is essential for advancing observational capabilities.

Purpose of the Study:

• To present the first results from the Hertz/VPM, a novel submillimeter polarimeter.
• To introduce the dual Variable-delay Polarization Modulator (dual-VPM) technology.
• To evaluate the performance and potential advantages of the dual-VPM over existing methods.

Main Methods:

• Detailed theoretical discussion of the dual-VPM's operational principles.
• Experimental testing of the dual-VPM at the Submillimeter Telescope Observatory.
• Laboratory-based validation of the polarimeter's performance.
• Analysis of wire grid properties and their impact on performance.

Main Results:

• The dual-VPM operates via translation, differing from rotational modulators.
• Observed VPM wire grid behavior deviated from ideal theoretical predictions.
• Modified polarimeter settings compensated for observed deviations.
• The dual-VPM system demonstrated robustness, high efficiency, and low instrumental polarization.

Conclusions:

• The dual-VPM is a viable and effective technology for submillimeter polarimetry.
• The system's robustness and performance make it suitable for demanding applications.
• The dual-VPM shows promise for future air- and space-borne astronomical missions.