Regensburg 2019 – wissenschaftliches Programm
HL 45.38: Poster
Donnerstag, 4. April 2019, 18:30–21:00, Poster E
Sensing Weak Microwave Signals by Quantum Control — •Timo Joas, Andreas M. Waeber, Georg Braunbeck, and Friedemann Reinhard — Walter Schottky Institut und Physik-Department, Technische Universität München
Solid state qubits, such as the Nitrogen-Vacancy (NV) center in diamond, are attractive sensors for nanoscale magnetic and electric fields, owing to their atomically small size. A major key to their success have been dynamical decoupling protocols (DD), which enhance sensitivity to weak AC signals such as the field of nuclear spins from a single protein. However, those methods are currently limited to signal frequencies up to several MHz.
Here we harness a quantum-optical effect, the Mollow triplet splitting of a strongly driven two-level system, to overcome this limitation. We microscopically understand this effect as a pulsed DD protocol and find that it enables sensitive detection of fields close to the driven transition. To this end, we create a pair of photon-dressed qubit states which support a new transition with narrow linewidth. Generally, our scheme is applicable to any qubit but we consider sensitive detection of signals close to the NV’s transition frequency (≈ 2 GHz). As a result, we demonstrate slow Rabi oscillations with a period up to ΩRabi−1 ∼ T2 driven by a weak signal field. The corresponding sensitivity could enable various applications. Specifically, we consider single microwave photon detection, as well as fundamental research on spin-phonon coupling.