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arXiv · 2112.14990

Position measurement of a levitated nanoparticle via interference with its mirror image

Lorenzo Dania·Katharina Heidegger·Dmitry S. Bykov·Giovanni Cerchiari·Gabriel Araneda·Tracy E. Northup
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Abstract

Interferometric methods for detecting the motion of a levitated nanoparticle provide a route to the quantum ground state, but such methods are currently limited by mode mismatch between the reference beam and the dipolar field scattered by the particle. Here we demonstrate a self-interference method to detect the particle's motion that solves this problem. A Paul trap confines a charged dielectric nanoparticle in high vacuum, and a mirror retro-reflects the scattered light. We measure the particle's motion with a sensitivity of $1.7\times 10^{-12} \text{m}/\sqrt{\text{Hz}}$, corresponding to a detection efficiency of 2.1%, with a numerical aperture of 0.18. As an application of this method, we cool the particle, via feedback, to temperatures below those achieved in the same setup using a standard position measurement.

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Lorenzo Dania, Katharina Heidegger, Dmitry S. Bykov, Giovanni Cerchiari, Gabriel Araneda, Tracy E. Northup. 2021-12-30. Position measurement of a levitated nanoparticle via interference with its mirror image. https://doi.org/10.1103/physrevlett.129.013601

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