Technology for SPT-SLIM and Line-Intensity Mapping

LIM at millimeter wavelengths is a potentially powerful probe of large-scale structure, but achieving meaningful constraints on cosmological parameters requires focal planes with orders of magnitudes more detectors than existing instruments. SPT-SLIM is an upcoming experiment to demonstrate line-intensity mapping (LIM) of CO at 0.5 < z < 2.0 using on-chip spectrometers with kinetic inductance detectors (KIDs), a technology that should enable scaling to much larger arrays of detectors. In 2023, SPT-SLIM will deploy on the South Pole Telescope with 9,000 KIDs arranged into filter-bank spectrometers coupled to 18 dual-polarization spatial pixels and new room-temperature microwave readout electronics. I will describe the overall experimental design and the technology development for detectors, readout, and cryogenics that will enable SPT-SLIM to realize its significant improvements in mapping speed.