We describe a technique to measure the position of a dipolar scatterer based on self-homodyne detection of the scattered light. The method can theoretically reach the Heisenberg limit, at which information gained about the position is constrained only by the back action of the scattered light. The technique has applications in the fields of levitated optomechanics and trapped ions and is generally applicable to the position determination of confined light scatterers.

• Received 16 March 2021
• Revised 28 September 2021
• Accepted 20 October 2021

DOI:https://doi.org/10.1103/PhysRevA.104.053523

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Published by the American Physical Society