Trapped Ion Sensor Characterizes Sub-Wavelength Fields with 40nm X 40nm X 180nm Resolution

Characterizing light fields at the nanoscale presents a significant challenge, yet is crucial for advances in fields ranging from quantum computing to advanced lithography. Now, Nikhil Kotibhaskar, Sainath Motlakunta, Anthony Vogliano, Lewis Hahn, and Rajibul Islam demonstrate a novel technique to measure both the intensity and polarization of light at the ultimate limit of spatial resolution. The team utilizes a single, trapped atomic ion, confined to an area smaller than the wavelength of the light itself, as a sensor, effectively bypassing the limitations of conventional measurement tools. This innovative approach not only allows for unprecedented characterization of sub-wavelength light fields, but also incorporates a machine learning algorithm that accelerates data analysis by a factor of 100,000, paving the way for practical, field-deployable nanoscale optical metrology.

Yb+ Ion Interactions with Light and Microwaves

This work details a comprehensive theoretical model for simulating how Yb+ ions interact with light and microwave fields. The model accounts for fundamental processes like spontaneous emission and decoherence, crucial for understanding and predicting the ion’s behavior in applications such as quantum computing, precision spectroscopy, and atomic clocks. The research aims to create an accurate yet computationally manageable simulation of these interactions. The model quantifies the strength of the interaction between the ion and applied fields, known as the Rabi frequency, determining how quickly the ion transitions between energy levels.

Researchers also consider the saturation intensity and spontaneous emission rate. Calculations rely on reduced matrix elements and established principles like the Wigner-Eckart theorem and Fermi’s Golden Rule. To account for decoherence, the research employs the Lindblad Master Equation, describing how the ion’s quantum state evolves over time. Collapse operators within the equation represent the impact of spontaneous emission and other decoherence mechanisms. The team developed a method to simplify calculations by leveraging graph theory, removing time dependence from the Hamiltonian by ensuring balanced effective detunings around closed loops, improving computational efficiency. The model’s complexity requires significant computational resources, and the simplification techniques are essential for practical simulations. This model provides a powerful tool for simulating phenomena involving Yb+ ions, with potential applications in diverse fields.

Ion Confinement Maps Sub-Wavelength Light Fields

Scientists have developed a novel technique to characterize light fields at the sub-wavelength scale, achieving a resolution previously unattainable. The method utilizes a single, trapped atomic ion, confined to a space approximately 40nm x 40nm x 180nm, as a sensor to measure both the intensity and polarization of light. This innovative approach overcomes limitations in characterizing advanced optical systems by employing an exceptionally small sensor. The technique relies on constructing an analytical model describing the interaction between the ion and the light field, allowing researchers to extract detailed information about the light’s properties.

The team obtained 88 experimental curves, using 76 for fitting the model and 12 for independent validation. The fitting process began with an initial guess and then refined parameters to minimize the error between experimental data and model predictions. To demonstrate the technique’s high spatial resolution, scientists mapped the beam profile of the characterization beam by moving it in 200nm increments using Fourier holography. They reconstructed the beam profile along both the X and Y directions with a single optical pumping measurement and a fixed interaction time of 30μs. Researchers also devised an intelligent sensing strategy that exploits the internal energy structure of the 171Yb+ ion and atomic selection rules, reducing computational burden and enabling the characterization of large areas with improved speed and precision.

Atomic Ion Senses Sub-Wavelength Light Fields

Scientists have developed a groundbreaking technique to characterize light fields at the sub-wavelength scale, achieving a spatial resolution previously unattainable. The method utilizes a single, trapped atomic ion, confined to a space approximately 40nm x 40nm x 180nm, as a sensor to measure both the intensity and polarization of light with exceptional precision. This innovative approach offers a new standard for assessing light fields at extremely fine resolutions. Experiments involved repeatedly measuring the optical pumping of the ion, collecting data from 200 separate measurements. By carefully modeling the interaction between the ion and the light, scientists can accurately determine the intensity and polarization of the light field.

The team successfully validated their model by comparing predicted optical pumping curves with experimental data, achieving a high degree of accuracy with 76 curves used for fitting and 12 for independent validation. To further enhance the technique’s efficiency, researchers employed a deep neural network, a form of machine learning, to accelerate the data analysis process. This resulted in a remarkable five orders of magnitude speed-up in determining light intensity and polarization, making the technique practical for real-time, field-deployable applications. Scientists mapped the beam profile of the characterization beam by moving it in 200nm increments, revealing detailed information about the light’s distribution. This advancement promises to revolutionize the characterization of high-resolution optical instruments, enabling the development of more precise and efficient technologies in fields ranging from microscopy to lithography.

Ion Sensor Maps Sub-Wavelength Light Fields

This research presents a novel technique for characterizing light fields at the sub-wavelength scale, a capability previously unavailable to scientists and engineers. The team successfully demonstrated that a single, trapped atomic ion can function as a highly sensitive sensor, detecting both the intensity and polarization of light with exceptional spatial resolution. This is achieved by precisely measuring the ion’s response to the light field and then using a model to interpret the data, revealing details smaller than the wavelength of the light itself. Importantly, the researchers also developed a machine learning algorithm that significantly speeds up the data analysis process, reducing the readout time by five orders of magnitude and making the technique practical for real-world applications.

This advancement enables the characterization of instruments and optical setups at a level of detail previously unattainable, with potential implications for fields like nanophotonics and advanced microscopy. The authors acknowledge that the current method relies on a carefully calibrated model and that further work is needed to improve the robustness and generalizability of the technique. Future research may focus on expanding the technique to characterize more complex light fields and integrating it into existing optical systems.