Builds radio and mm-wave quantum-limited sensing instruments for high-energy astrophysics and cosmology. Directions: (1) PUEO — balloon-borne radio Cherenkov (Askaryan) detector for ultra-high-energy cosmogenic neutrinos; (2) RNO-G — ground-based radio neutrino array at Summit Station, Greenland; (3) UHE cosmic ray radio detection methodology; (4) CMB instrumentation (BICEP/Keck, SPT, CMB-S4). 2025 APS Fellow; 2022 Moore EPII award. Director KICP.