Mid-Infrared Control of ⁸⁸Sr in Magic-Wavelength Optical Tweezers

We demonstrate a platform for studying the strontium mid-infrared (IR) 2923 nm 5s5p ³P₂ - 5s4d ³D₃ transition in magic-wavelength optical tweezers. Using a novel, visible trapping wavelength, we demonstrate single-atom preparation and imaging. We measure the differential polarizability between 5s5p ³P₂ and 5s4d ³D₃ with tightly confined single atoms and confirm a magic wavelength for the m_J = |2| - m_J = |3| transition. Using this trapping wavelength, we demonstrate resolved sideband cooling of atoms in a metastable state for the first time. With these demonstrations, we unlock an important tool—mid-IR control—for existing Sr experiments. Combined with our previously demonstrated holographic metasurfaces for densely spaced tweezers [1], this platform opens a path towards exploring collective photon dynamics in extended atomic arrays.