A quantum radio frequency signal analyzer based on nitrogen vacancy centers in diamond

Abstract

The rapid development of radio-frequency (RF) technologies requires tools which can efficiently monitor the electromagnetic landscape. Broadband real-time RF spectral analyzers need to operate at room temperature, with low power consumption and have a compact design for on-board device integration. Here we describe a Quantum Diamond Signal Analyzer (Q-DiSA) which detects RF signals over a tunable frequency range of 25 GHz with frequency resolution down to 1 MHz, a millisecond temporal resolution and a large dynamic range (40 dB). This approach exploits the room temperature spin properties of an ensemble of nitrogen-vacancy (NV) centers in diamond. Performance is enabled via our analyzer architecture which combines a specific diamond crystallographic cut with a simplified magnetic arrangement. This allows us to maintain the alignment of the magnetic field along the nitrogen-vacancy center axis whilst frequency tuning. These results demonstrate the potential of the Q-DiSA method for real-time broadband spectral analysis.

A compact radiofrequency spectrum analyzer based on nitrogen-vacancy centers in diamond

“…The bright lines show the linear dependence of the resonance frequency with the magnetic field. The other lines are due to harmonics of the fundamental RF signal and can be used to evaluate the dynamics of the detection [3]. In this range, the RF sensitivity is of the order of 100 µW and the frequency resolution of a few MHz.…”

“…The proof of principle of this technique had been first established by demonstrating the coverage of a band of a few hundred MHz around 2 GHz and where the main technical limitation came from the constraint related to the alignment of the magnetic field with respect to the NV centers [2]. In a subsequent demonstration, we have extended the frequency range up to 25 GHz [3]. Here, we describe a compact device comprising a diamond crystal with a specific cut, a ring magnet to create the magnetic field gradient aligned with the pump laser at 532 nm and a compact antenna to bring the RF signal in the vicinity of the diamond crystal (Figure 2).…”

“…The fluorescence of the NV centers is imaged on a CMOS detector array using a gradient index lens. This makes possible a much more compact imaging device as compared to previous implementations [3], while preserving a good image quality. The laser beam is focused through the ring magnet and aligned with the magnetic field gradient.…”

Quantum enhanced radio detection and ranging with solid spins

“…It is operated with simple setup under ambient condition. The working frequency band can be adjusted through Zeeman effect to tens of GHz [44,45]. And the CMOS-compatibility of diamond is favored for the development of a compact and integrated quantum sensor [46,47].…”

Fast, Broad-Band Magnetic Resonance Spectroscopy with Diamond Widefield Relaxometry

“…This allowed us to perform fast-high bandwidth spectroscopy of a microwave signal by imaging the NV center photoluminescence directly. This method has recently been further expanded up to a range of 25 GHz and a 40 dB dynamics . Here we use a similar magnetic gradient to spread the NV center and target spin resonances in space (Figure B, C).…”