Exploring Low-Loss Materials for Millimeter-Wave Astronomical Instruments
Abstract: Millimeter-wave astronomy offers a powerful window into a wide range of cosmological and astrophysical phenomena, including line-intensity mapping, which probes the aggregate emission from unresolved spectral lines across large cosmic volumes. Achieving the spectral resolution required for these measurements, however, depends critically on the performance of low-loss materials within the instrument.
In several on-chip millimeter-wave spectrometer architectures, dielectric loss appears to be a limiting factor. This challenge is especially acute in devices incorporating aluminum superconducting resonators, where dielectric films must be deposited below about 200 °C to avoid degrading or deforming the resonator structures.
In this work, we investigate low-temperature dielectric recipes based on hydrogenated and carbonized silicon deposited at or below 150 °C. We characterize these materials using both microwave resonators near 1 GHz and millimeter-wave resonators near 150 GHz, with measurements spanning temperatures from 100 mK to 1 K.
Our results explore the loss behavior of these silicon-rich dielectrics across the frequency and temperature regimes relevant to superconducting detector and spectrometer technologies. These materials provide a promising pathway toward low-temperature, low-loss dielectric integration in superconducting devices for future millimeter-wave astronomical instruments.
View event: https://indico.fnal.gov/event/73952/