arXiv:2410.03241 · Nature Communications
Atom camera: super-resolution scanning microscope of a light pattern with a single ultracold atom
Takafumi Tomita, Yuki Torii Chew, René A. Villela, Tirumalasetty Panduranga Mahesh, Hiroto Sakai, Keisuke Nishimura, Taro Ando, Sylvain de Léséleuc, Kenji Ohmori
Abstract
Sub-micrometer light patterns play a pivotal role in biology, biophysics, and AMO physics, yet their in situ characterization is limited in spatial resolution and sensitivity. Here, we present an atom camera with a single ultracold atom in an optical tweezer as a scanning probe. Measuring the energy shift on the spin states with the long coherence time and polarization-sensitive transitions yields highly sensitive, high-resolution 2D imaging of both intensity and polarization ellipticity. We characterize the polarization of a tightly-focused beam, observing its non-trivial profile. The spatial resolution is fundamentally limited by the atom’s position uncertainty, suppressed down to quantum fluctuations (~25 nm) in the motional ground state of the tweezer, with an experimentally obtained upper bound of σ ≤ 96(4) nm. This method enables imaging beyond the diffraction limit, surpassing previous approaches limited by thermal fluctuations of the atom, and provides a powerful tool for designing and analyzing submicron-scale light patterns. In situ super-resolution imaging of light has inherent limitations when applied to the polarization profile. Here, the authors introduce an “atom camera” approach by means of a single tweezer-trapped 87Rb atom measuring the field-induced shifts at sub-micrometer steps, achieving resolution beyond the optical diffraction limit.