Zeptonewton force sensing with nanospheres in an optical lattice

TL;DR

This paper demonstrates zeptonewton force sensing using laser-cooled silica nanospheres in an optical lattice, achieving high sensitivity and long measurement times for applications like gravimetry and inertial sensing.

Contribution

It introduces a method for ultra-sensitive force detection with nanospheres in an optical lattice, surpassing conventional sensors and enabling precise localization and calibration.

Findings

Achieved force sensitivity below 1 zN.

Measurement times exceeded 10^5 seconds.

Demonstrated stable trapping and calibration techniques.

Abstract

Optically trapped nanospheres in high-vaccum experience little friction and hence are promising for ultra-sensitive force detection. Here we demonstrate measurement times exceeding $10^5$ seconds and zeptonewton force sensitivity with laser-cooled silica nanospheres trapped in an optical lattice. The sensitivity achieved exceeds that of conventional room-temperature solid-state force sensors, and enables a variety of applications including electric field sensing, inertial sensing, and gravimetry. The optical potential allows the particle to be confined in a number of possible trapping sites, with precise localization at the anti-nodes of the optical standing wave. By studying the motion of a particle which has been moved to an adjacent trapping site, the known spacing of the lattice anti-nodes can be used to calibrate the displacement spectrum of the particle. Finally, we study the dependence of the trap stability and lifetime on the laser intensity and gas pressure, and examine the heating rate of the particle in high vacuum in the absence of optical feedback cooling.