Microwave Cavity Readout of an Ensemble Solid-State Spin Sensor

Quantum systems, especially ones based on spin defect centers, are key elements of high-performance sensors and quantum information technologies. However, the measurement of these systems is often plagued by limitations, such as low visibility and sensitivity, as well as noise interference. Current measurement techniques, such as fluorescence detection, seldomly produce satisfactory results because of their inherent inefficiencies and limitations. Fluorescence measurement, one of the prevalent techniques, suffers from poor fidelity and is hindered by shot noise, which is detrimental to high-precision readouts. Its shortcomings also include a lack of sensitivity and low signal-to-noise ratio that often cause inaccuracies in measuring the subtle shifts in spin defect center resonances caused by physical parameters. These issues have necessitated the need for a more superior technology.

Technology Description

The microwave resonator readout is a high-performance measurement technology aimed at analyzing the interaction between a spin defect center ensemble and a microwave resonator. This method employs microwave photons to probe a microwave resonator that is connected to a spin defect center ensemble affected by a physical parameter to be measured. Notably, this physical parameter modifies the spin defect centers' resonances, which subsequently influences the dispersion and/or absorption of the microwave resonator. The groundbreaking feature of this technology is its superior visibility, reduced shot noise, enhanced sensitivity and higher signal-to-noise ratio compared to conventional fluorescence measurement. The readout technology allows for a more clear, concise, and accurate capture of data, effectively increasing the fidelity of the results. Additionally, the microwave resonator readout technology permits coherent averaging of spin defect center ensembles and is adaptable to spin systems beyond nitrogen vacancies in diamonds.