Trapping atoms closer together than the light they emit

When atoms are packed closer together than the wavelength of light they emit, they can radiate collectively in exotic ways — but achieving this geometry has been nearly impossible with visible-light emitters. By exploiting a mid-infrared transition in strontium at 2,923 nm, this team placed atoms in micron-spaced optical tweezers that are genuinely subwavelength, demonstrating single-atom control and laser cooling along the way. The platform unlocks tabletop experiments on superradiance, dipolar quantum matter, and improved strontium qubits.