A Wavefunction Microscope for Ultracold Atoms*

New imaging techniques that enhance optical resolution have proven important in opening new areas of study, particularly in biological systems. The size of the features that can be optically resolved is typically limited by diffraction to the wavelength of light used to image; the field of super-resolution imaging has developed to find ways around this. We exploit the nonlinearity of an atom coupled to two laser fields to massively beat the diffraction limit by demonstrating a resolution of lambda/50.

We use this sub-wavelength imaging to study the static and dynamic properties of wavefunctions of atoms in optical lattices. We use dynamic light fields to locally flip the spin composition of a narrow slice of the wavefunction to be imaged. By choosing the position of the narrow slice and selectively imaging atoms only within this slice, we can recreate the target wavefunction. The technique has fast measurement times, allowing us to study the static and dynamic properties of the atomic wavefunction.

By bringing super-resolution imaging to cold atomic systems, we add a new technique to the atomic physics toolbox. This will allow for new direct probes of the atomic wavefunction in a variety of many-body systems.