Line intensity mapping (LIM) is a new astrophysical probe that builds three-dimensional maps of the high-redshift universe by tracing atomic and molecular emission lines across cosmic time. Importantly, LIM bridges the gap between galaxy surveys of our late-time universe and the earliest light from the cosmic microwave background, probing the “middle ages” of cosmic history that remain largely unexplored. This technique promises a new view of star formation, galaxy evolution, and large-scale structure, and is poised for rapid progress as detector technology reaches the sensitivity and scalability needed for competitive cosmological and astrophysical surveys.
I will describe the cameras and analysis techniques behind two of the first LIM experiments: the South Pole Telescope Shirokoff Line Intensity Mapper (SPT-SLIM), a millimeter-wave CO LIM experiment, and the Terahertz Intensity Mapper (TIM), a NASA balloon mapping [CII] in the far-infrared. I will describe the successful test flight of TIM and present the first results from SPT-SLIM, including on-sky measurements from January 2025. I will conclude by describing the instrumentation I am developing for the next generation of LIM cameras, to realize LIM as a powerful astrophysical probe for years to come.