A research group including Assistant Professor Takafumi Tomita and Professor Kenji Ohmori at the Institute for Molecular Science has developed a new microscopic observation technique called the "atom camera." By using a single ultracold atom, which is captured via optical tweezers and cooled to near absolute zero, as a camera, the technology visualizes light intensity and polarization distribution at the nanometer scale. The team successfully imaged the intensity and polarization distribution of patterns of finely structured light with a spatial resolution that surpasses the diffraction limit of conventional optical microscopes. The findings were published in Nature Communications.
The research group utilized a single rubidium atom as a probe, sweeping it across space with nanometer-level precision using optical tweezers. By measuring changes in the energy of the atom's internal spin state, they obtained localized information about the light at each position. From this energy shift data, they succeeded in visualizing the distribution of light intensity. Furthermore, noting that the amount of energy shift in the spin depends not only on the intensity of the light but also on its polarization, the group successfully performed direct observation of the light's polarization distribution.
To evaluate its performance, they demonstrated the ability to visualize the unique polarization structure that emerges in a laser beam tightly focused by a lens to a narrow area of approximately 1 micrometer. The probe atom is cooled via laser cooling to its lowest possible quantum mechanical energy state within the optical tweezers.
In principle, the measurement resolution is determined by the quantum mechanical positional fluctuation of a single atom (approximately 25 nanometers under these experimental conditions), enabling optical measurements on an extremely small spatial scale.
In their experiments, the team demonstrated a spatial resolution of less than 100 nanometers. The resolution significantly exceeds the diffraction limit of standard optical microscopy.
Technologies for the high-precision measurement of fine structures in light are used in neutral-atom quantum computers and simulators, fields that have seen rapid development in recent years, for understanding and controlling the structure of laser beams that control neutral atoms.
Because the atoms serving as qubits in these computers change their behavior based on both the intensity and the polarization of laser light, the atom camera represents a powerful tool for measuring both parameters simultaneously.
Journal Information
Publication: Nature Communications
Title: Atom camera: super-resolution scanning microscope of a light pattern with a single ultracold atom
DOI: 10.1038/s41467-026-73348-x
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