Fabrication Development for SPT-SLIM, a Superconducting Spectrometer for Line Intensity Mapping

Line Intensity Mapping (LIM) is a new observational technique that uses low-resolution observations of line emission to efficiently trace the large-scale structure Universe out high redshift. Common mm/sub-mm lines are accessible from ground-based observatories, and requirements on detectors for LIM at mm-wavelengths well matched capabilities large-format arrays superconducting sensors. We describe development an $R$ = notation="LaTeX">$\lambda / \Delta \lambda 300$ on-chip filter-bank spectrometer covering 120–180 GHz band future mm-LIM experiments, focusing SPT-SLIM, pathfinder instrument South Pole Telescope. Radiation coupled telescope optical system chip via array feedhorn-coupled orthomode transducers. Superconducting microstrip transmission then carry signal channelizing half-wavelength resonators, output each spectral channel sensed by lumped element kinetic inductance detector (leKID). Key areas include incorporating low-loss dielectrics improve both achievable resolution efficiency robust fabrication process create galvanic connection between ultra-pure thin-films realize multi-material (hybrid) leKIDs. provide overview design, process, prototype devices.