Speaker
Description
As CMB telescopes—such as the current and upcoming BICEP/Keck instruments and the future CMB‐S4 experiment—strive to measure primordial B-modes via precise polarimetry, rigorous characterization of optical materials under cryogenic conditions is increasingly critical. For instance, losses in transmissive optics elevate photon noise, degrading mapping speed and overall sensitivity. Meeting the stringent demands of these high-contrast, high-throughput imaging systems requires a precise understanding of the complex permittivity of laminates and bulk materials, which in turn guides the design of optical components such as anti‐reflection coatings and refractive elements.
To address these challenges, we have commissioned a series of high-quality factor quasioptical Fabry–Pérot resonant cavities that span 75 GHz - 330 GHz and that are compatible with a quick-turnaround 4 K cryostat. These hemispherical resonators enable precise metrology of low-loss bulk and thin dielectrics used as lenses, filters, and laminates throughout the optical chain. These developments not only refine our understanding of photon loading in current instruments, such as BICEP3 and BICEP Array, but also inform the selection of materials in the design of upcoming CMB telescopes. Ultimately, our results also broadly contribute to wide-ranging mm-wave instrumentation efforts. We discuss the development, design, and characterization of these cavities, as well as measurements of the index and loss of various materials commonly employed in millimeter-wave instruments.
| Would you be interested in presenting a poster if the conference is oversubcribed? | Yes |
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