Description
Developing high bandwidth portable quantum sensors is of significant importance for both terrestrial and satellite communications. The nitrogen vacancy center in diamond is a popular quantum sensing platform for its relative simplicity and wide range of acceptable operating conditions, but suffers from a limited instantaneous bandwidth due to the narrow MHz-scale linewidth of the magnetic resonance. In this work, we present a magnetic quantum sensing scheme in diamond utilizing heterodyne mixing with strong optical and microwave driving, expanding the kHz-scale bandwidth of previous heterodyne demonstrations and achieving MHz-scale instantaneous bandwidth with a sensitivity of 548 pT/√Hz in a diamond volume of 2.5×10-4 mm3 containing 2×1011 NV centres. We then demonstrate expansion of the sensing bandwidth by employing a strong magnetic gradient and code-division multiplexing of the heterodyne signal using individually modulated microwave control fields. This bandwidth expansion scheme broadens the FWHM bandwidth of the diamond sensor by well over an order of magnitude to 48 MHz, with which we achieve a peak sensitivity of 8.5 nT/√Hz.
| I am the presenting author | Yes |
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