Quantum Sensing in Tweezer Arrays: Optical Magnetometry on an Individual-Atom Sensor Grid

Abstract

We implement a scalable platform for quantum sensing comprising hundreds of sites capable of holding individual laser-cooled atoms and demonstrate the applicability of this single-quantum-system sensor array to magnetic field mapping on a two-dimensional grid. With each atom being confined in an optical tweezer within an area of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:mrow><a:mn>0.5</a:mn></a:mrow><a:mspace width="0.2em"/><a:mtext>μ</a:mtext><a:msup><a:mrow><a:mi mathvariant="normal">m</a:mi></a:mrow><a:mn>2</a:mn></a:msup></a:math> at mutual separations of <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><f:mrow><f:mn>7.0</f:mn><f:mo stretchy="false">(</f:mo><f:mn>2</f:mn><f:mo stretchy="false">)</f:mo></f:mrow><f:mspace width="0.2em"/><f:mtext>μ</f:mtext><f:mrow><f:mi mathvariant="normal">m</f:mi></f:mrow></f:math>, we obtain micrometer-scale spatial resolution and highly parallelized operation. An additional steerable optical tweezer allows rearrangement of atoms within the grid and enables single-atom scanning microscopy with submicron resolution. This individual-atom sensor platform finds an immediate application in mapping an externally applied dc gradient magnetic field. In a Ramsey-type measurement, we obtain a field resolution of 98(29) nT. We estimate the sensitivity to be <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><m:mn>25</m:mn><m:mspace width="0.2em"/><m:mtext>μ</m:mtext><m:mrow><m:mi mathvariant="normal">T</m:mi></m:mrow><m:mo>/</m:mo><m:msqrt><m:mi>Hz</m:mi></m:msqrt></m:math>. Published by the American Physical Society 2024