Abstract

Quantum sensors that use solid state spin defects are effective probes of weak alternating magnetic signals. This work presents a continuous microwave-drive sensing scheme based on continuous concatenated dynamical decoupling that extends coherence toward the effective T₂ ≈ 1/2 T₁ limit and enables detection of the frequency, amplitude, and phase of GHz magnetic fields. The protocol is demonstrated using an ensemble of boron vacancies in hexagonal boron nitride, achieving microtesla-scale amplitude sensitivity, phase sensitivity of about 0.076 rad/√Hz, and sub-Hz frequency resolution over a 10 s measurement.

Abstract

Quantum sensors that use solid state spin defects are effective probes of weak alternating magnetic signals. This work presents a continuous microwave-drive sensing scheme based on continuous concatenated dynamical decoupling that extends coherence toward the effective T₂ ≈ 1/2 T₁ limit and enables detection of the frequency, amplitude, and phase of GHz magnetic fields. The protocol is demonstrated using an ensemble of boron vacancies in hexagonal boron nitride, achieving microtesla-scale amplitude sensitivity, phase sensitivity of about 0.076 rad/√Hz, and sub-Hz frequency resolution over a 10 s measurement.

Abstract

Quantum sensors that use solid state spin defects are effective probes of weak alternating magnetic signals. This work presents a continuous microwave-drive sensing scheme based on continuous concatenated dynamical decoupling that extends coherence toward the effective T₂ ≈ 1/2 T₁ limit and enables detection of the frequency, amplitude, and phase of GHz magnetic fields. The protocol is demonstrated using an ensemble of boron vacancies in hexagonal boron nitride, achieving microtesla-scale amplitude sensitivity, phase sensitivity of about 0.076 rad/√Hz, and sub-Hz frequency resolution over a 10 s measurement.

Abstract

Quantum sensors that use solid state spin defects are effective probes of weak alternating magnetic signals. This work presents a continuous microwave-drive sensing scheme based on continuous concatenated dynamical decoupling that extends coherence toward the effective T₂ ≈ 1/2 T₁ limit and enables detection of the frequency, amplitude, and phase of GHz magnetic fields. The protocol is demonstrated using an ensemble of boron vacancies in hexagonal boron nitride, achieving microtesla-scale amplitude sensitivity, phase sensitivity of about 0.076 rad/√Hz, and sub-Hz frequency resolution over a 10 s measurement.