Optimal displacement detection of arbitrarily shaped levitated dielectric objects using optical radiation
Phys. Rev. A 113, 063529 – Published 25 June, 2026
DOI: https://doi.org/10.1103/d2gn-pwd1
Abstract
Optically levitated dielectric objects are promising for precision force, acceleration, torque, and rotation sensing due to their extreme environmental decoupling. While many levitated optomechanics experiments employ spherical objects, for some applications nonspherical geometries offer advantages. For example, rod-shaped or dumbbell-shaped particles have been demonstrated for torque and rotation sensing, and high-aspect-ratio plate-like particles can exhibit reduced photon recoil heating and may be useful for high-frequency gravitational wave detection or as high-bandwidth accelerometers. To achieve optimal sensitivity, cooling, and quantum control in these systems, it is beneficial to achieve optimal displacement detection using scattered light. We describe and numerically implement a method based on Fisher information that is applicable to suspended particles of arbitrary geometry. We demonstrate the agreement between our method and prior methods employed for spherical particles, in both the Rayleigh and Lorentz-Mie regimes. As practical examples, we analyze the optical detection limits of an optically levitated high-aspect-ratio disk-like dielectric object and a rod-shaped object for configurations recently realized in experimental work.
