Color centers in silicon carbide have become potentially versatile quantum sensors. Particularly, wide temperature range temperature sensing has been realized in recent years. However, the sensitivity is limited due to the short dephasing time of the color centers. In this work, we realize a high sensitivity silicon carbide divacancy-based thermometer using the thermal Carr-Purcell-Meiboom-Gill (TCPMG) method. First, the zero field splitting D of PL6 divacancy as a function of temperature is measured with a linear slope of -99.7 kHz/K. The coherence times of TCPMG pulses linearly increase with the pulse number and the longest coherence time is about 21 us, which is ten times larger than dephasing time. The corresponding temperature sensing sensitivity is 13.4 mK/Hz1/2, which is about 15 times higher than previous results. Finally, we monitor the laboratory temperature variations for 24 hours using the TCMPG pulse. The experiments pave the way for the applications of silicon carbide-based high sensitivity thermometer in the semiconductor industry, biology, and materials sciences.
Color centers in silicon carbide have become potentially versatile quantum sensors. Particularly, wide temperature range temperature sensing has been realized in recent years. However, the sensitivity is limited due to the short dephasing time of the color centers. In this work, we realize a high sensitivity silicon carbide divacancy-based thermometer using the thermal Carr-Purcell-Meiboom-Gill (TCPMG) method. First, the zero field splitting D of PL6 divacancy as a function of temperature is measured with a linear slope of -99.7 kHz/K. The coherence times of TCPMG pulses linearly increase with the pulse number and the longest coherence time is about 21 us, which is ten times larger than dephasing time. The corresponding temperature sensing sensitivity is 13.4 mK/Hz1/2, which is about 15 times higher than previous results. Finally, we monitor the laboratory temperature variations for 24 hours using the TCMPG pulse. The experiments pave the way for the applications of silicon carbide-based high sensitivity thermometer in the semiconductor industry, biology, and materials sciences.
We presented a high-sensitivity temperature detection using an implanted single nitrogen-vacancy (NV) center array in diamond. The high-order thermal Carr-Purcell-Meiboom-Gill (TCPMG) method was performed on the implanted single NV center in diamond in a static magnetic field. We demonstrated that under small detunings for the two driving microwave frequencies, the oscillation frequency of the induced fluorescence of the NV center equals approximately the average of the detunings of the two driving fields. On the basis of the conclusion, the zero-field splitting D for the NV center and the corresponding temperature could be determined. The experiment showed that the coherence time for the high-order TCPMG was effectively extended, particularly up to 108 $\ensuremath{\mu}\mathrm{s}$ for TCPMG-8, about 14 times the value 7.7 $\ensuremath{\mu}\mathrm{s}$ for thermal Ramsey method. This coherence time corresponded to a thermal sensitivity of 10.1 mK/Hz1/2. We also detected the temperature distribution on the surface of a diamond chip in three different circumstances by using the implanted NV center array with the TCPMG-3 method. The experiment implies the feasibility of using implanted NV centers in high-quality diamonds to detect temperatures in biology, chemistry, materials science, and microelectronic systems with high sensitivity and nanoscale resolution.
As a cutting-edge quantum information research system at the intersection of "quantum information" and "integrated circuits", silicon carbide color center has become one of the important solid-state quantum systems in recent years. Silicon carbide color center system has the following characteristics :1) Silicon carbide is a mature semiconductor material, quantum information technology based on silicon carbide color center is easy to integrate with semiconductor industry technology; 2) Silicon carbide color center fluorescence in the near infrared band, which is conducive to transmission in optical fiber communication network; 3) Silicon carbide color center spin coherence time is long, easy to perform more quantum algorithms. This report mainly introduces the research progress of quantum control and quantum precision measurement of silicon carbide color centers, including the basic knowledge of silicon carbide color centers, the preparation, observation and quantum control of its spin quantum states, as well as the application of this system in the fields of quantum control and quantum precision measurement.
Silicon carbide is an emerging platform for quantum technologies that provides wafer scale and low-cost industrial fabrication. The material also hosts high-quality defects with long coherence times that can be used for quantum computation and sensing applications. Using an ensemble of nitrogen-vacancy centers and an XY8-2 correlation spectroscopy approach, we demonstrate a room-temperature quantum sensing of an artificial AC field centered at ~900 kHz with a spectral resolution of 10 kHz. Implementing the synchronized readout technique, we further extend the frequency resolution of our sensor to 0.01 kHz. These results pave the first steps for silicon carbide quantum sensors toward low-cost nuclear magnetic resonance spectrometers with a wide range of practical applications in medical, chemical, and biological analysis.
The nitrogen-vacancy (NV) center in diamond is an ideal candidate for quantum sensing because of its excellent spin coherence property as well as the possibility for optical initialization and readout. Previous studies, on the other hand, have typically been conducted at low or room temperature. The inability to fully understand the coherence properties of the NV center at high temperatures limits NV's further applications. We systematically investigate the coherence properties of NV center ensemble at temperatures ranging from 300 K to 600 K in this paper. Coherence time T2 decreases rapidly from $184\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\text{s}$ at 300 K to $30\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\text{s}$ at 600 K due to the interaction with paramagnetic impurities. At all experiment temperatures, both single-quantum and double-quantum transitions exhibit a T5 relaxation rate, which is attributed to the two-phonon Raman process. Nonetheless, the inhomogeneous dephasing time T2∗ and thermal-echo decoherence time TTE remain almost unchanged at temperature up to 600 K. A thermal-echo-based thermometer is demonstrated to have a sensitivity of 41mK/Hz at 450 K. These findings will pave the way for NV-based high-temperature sensing and provide a more comprehensive understanding of solid-state qubit decoherence.
In the past decade, color centers in silicon carbide (SiC) have emerged as promising platforms for various quantum information technologies. There are three main types of color centers in SiC: silicon-vacancy centers, divacancy centers, and nitrogen-vacancy centers. Their spin states can be polarized by laser and controlled by microwave. These spin defects have been applied in quantum photonics, quantum information processing, quantum networks, and quantum sensing. In this review, we first provide a brief overview of the progress in single-color center fabrications for the three types of spin defects, which form the foundation of color center-based quantum technology. We then discuss the achievements in various quantum sensing, such as magnetic field, electric field, temperature, strain, and pressure. Finally, we summarize the current state of fabrications and quantum sensing of spin defects in SiC and provide an outlook for future developments.
Solid-state color-center spin defects provide a versatile platform for quantum sensing with applications ranging from nanoscale magnetometry to thermometry and electrometry. This review surveys recent progress in nitrogen-vacancy centers in diamond and defect spins in silicon carbide (SiC), with emphasis on their material properties, fabrication strategies, and coherence engineering. Key defect creation and optimization techniques, including ion implantation, femtosecond laser writing, focused ion beam nanofabrication, isotopic engineering, and surface passivation, are discussed in the context of improving spin coherence and optical performance. Fundamental quantum measurement protocols, optically detected magnetic resonance, Rabi oscillations, Ramsey interferometry, and spin echo, are reviewed as a hierarchical framework for characterizing spin control, dephasing, and intrinsic coherence. The review further highlights microscale sensing architectures and examines the growing role of machine learning in pulse optimization, adaptive estimation, and data-driven imaging. Finally, current challenges and future directions are outlined, focusing on scalability, environmental robustness, and autonomous operation. Together, these developments position diamond and SiC color centers as leading platforms for next-generation solid-state quantum sensors.