Variable-delay Polarization Modulators for Cryogenic Millimeter-wave Applications

Abstract

We describe the design, construction, and initial validation of the variable-delay polarization modulator (VPM) designed for the PIPER cosmic microwave background polarimeter. The VPM modulates between linear and circular polarization by introducing a variable phase delay between orthogonal linear polarizations. Each VPM has a diameter of 39 cm and is engineered to operate in a cryogenic environment (1.5 K). We describe the mechanical design and performance of the kinematic double-blade flexure and drive mechanism along with the construction of the high precision wire grid polarizers.

8 pages, 10 Figures, Submitted to Review of Scientific Instruments

References in corpus (6)

• The ARCADE 2 Instrument
• The Cosmology Large Angular Scale Surveyor (CLASS): 40 GHz optical design
• Properties of a Variable-delay Polarization Modulator
• A Translational Polarization Rotator
• The Hertz/VPM polarimeter: Design and first light observations
• Vector Reflectometry in a Beam Waveguide

Cited by in corpus (7)

• CLASS: The Cosmology Large Angular Scale Surveyor
• Design and development of an ambient-temperature continuously-rotating achromatic half-wave plate for CMB polarization modulation on the POLARBEAR-2 experiment
• The Primordial Inflation Polarization Explorer (PIPER)
• The Cosmology Large Angular Scale Surveyor Receiver Design
• Sub-Kelvin cooling for two kilopixel bolometer arrays in the PIPER receiver
• Anti-reflection Coated Vacuum Window for the Primordial Inflation Polarization ExploreR (PIPER) balloon-borne instrument
• Superfluid Liquid Helium Control for the Primordial Inflation Polarization Explorer Balloon Payload