In high vacuum, optically-levitated dielectric nanospheres achieve excellent decoupling from their environment, making them ideal for precision force sensing. We have shown that 300 nm silica spheres can be used for calibrated zeptonewton force measurements in a standing-wave optical trap. The sensitivity achieved exceeds that of any conventional room-temperature solid-state force sensor by over an order of magnitude, and enables a variety of applications including electric field sensing, inertial sensing, and gravimetry. I will describe our progress towards using these sensors for tests of the Newtonian gravitational inverse square law at micron length scales. Optically levitated dielectric objects also show promise for a variety of other applications, including searches for gravitational waves, and experiments in quantum optomechanics.

Date Published: 9 September 2019
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Proc. SPIE 11083, Optical Trapping and Optical Micromanipulation XVI, 110830S (9 September 2019); doi: 10.1117/12.2529792

Published in SPIE Proceedings Vol. 11083:
Optical Trapping and Optical Micromanipulation XVI
Kishan Dholakia; Gabriel C. Spalding, Editor(s)