Related Experiment Video
Updated: Jul 20, 2026
10:35
Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials
Published on: September 26, 2014
Achromatic half-wave plate for submillimeter instruments in cosmic microwave background astronomy: experimental
Giampaolo Pisano1, Giorgio Savini, Peter A R Ade
1University of Wales-Cardiff, UK. giampaolo.pisano@astro.cf.ac.uk
Applied Optics
|September 2, 2006
Summary
A new achromatic half-wave plate (HWP) was developed for cosmic microwave background (CMB) polarization experiments. This HWP demonstrates excellent performance across a wide frequency range, crucial for precise CMB measurements.
Area of Science:
- * Astrophysics and cosmology
- * Optics and photonics
Background:
- * Cosmic Microwave Background (CMB) polarization measurements require high-performance optical components.
- * Existing half-wave plates (HWPs) may have limitations in achromatic performance and operational frequency range.
Purpose of the Study:
- * To design, manufacture, and test a novel achromatic half-wave plate (HWP).
- * To ensure the HWP meets the stringent requirements for millimeter-wave CMB polarization experiments.
- * To characterize the HWP's performance across a broad frequency spectrum.
Main Methods:
- * Design based on the 5-plates Pancharatnam recipe.
- * Modeling of transmission, reflection, absorption, and phase shift versus frequency.
- * Testing with coherent radiation (back-wave oscillator) for modulation efficiency.
- * Testing with incoherent radiation (polarizing Fourier transform spectrometer - FTS) for frequency behavior.
Main Results:
- * The HWP operates effectively in the 85-185 GHz frequency range.
- * Optical performance model shows excellent agreement with FTS measurements.
- * Precise determination of HWP fast and slow axes achieved.
- * Performance characteristics, including cross-polarization estimates, are reported.
Conclusions:
- * The developed achromatic HWP is suitable for millimeter-wave CMB polarization experiments.
- * The design and testing validate the HWP's capability for precise polarization measurements.
- * The component offers a significant advancement for future CMB research.
