Reporter-Spin-Assisted <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:msub><mml:mi>T</mml:mi><mml:mn>1</mml:mn></mml:msub></mml:math> Relaxometry

The detection of fluctuating electromagnetic fields through single-spin relaxometry affords important insight into the dynamics solid-state systems and chemical processes, but its sensitivity is often limited by proximity sensor spin to target. This study proposes use an auxiliary reporter improve as much a factor 100, experimentally verifies method with single shallow nitrogen-vacancy center in diamond. work motivates development engineered relaxation sensors without need for optical initialization or readout.