Sensitivity of magnetometers that use color centers is limited by poor photon-collection and detection efficiency. In this paper, we present the details of a newly developed all-optical collection combined frequency-modulated microwave method. The proposed method achieves a high sensitivity in static magnetic-field detection both theoretically and experimentally. First, we demonstrate that this collection technique enables both a fluorescence collection as high as 40% and an efficient pump absorption. Subsequently, we exploit the optically detected magnetic resonance (ODMR) signal and quantitative magnetic detection of an ensemble of nitrogen vacancy (NV) centers, by applying a frequency-modulated (FM) microwave method followed by a lock-in technique on the resonance frequency point. Based on the results obtained using all-optical collection combined FM microwaves, we verified that the sensitivity of the magnetometer can achieve approximately 14 nT/√Hz at 1 Hz, using a discrete Fourier transform detection method experimentally. This method provides a compact and portable precision-sensor platform for measuring magnetic fields, and is of interest for fundamental studies in spintronics.

This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses’ quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW) value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups’ output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.

The integrated diamond nitrogen vacancy (NV) magnetometer has attracted considerable attention in recent years and presents high potential for its use in magnetic field detection in fields such as aerospace, medical, and agriculture. A laser with a large volume seriously hampers the integration and performance of magnetometers. To solve this problem, we proposed a 520-nm laser diode with an integrated NV magnetometer. The 520-nm laser diode has a high excitation efficiency and good performance with a small size. We introduced the key steps of designing an integrated magnetometer head and tested the performance, a magnetic field sensitivity of $20.77\,\,{n}T\,\,\cdot \,\,Hz^{-1/2}$ , and a shot noise sensitivity of $1.43\,\,{n}T\,\,\cdot \,\,Hz^{-1/2}$ . The measurable magnetic field range is from −107 to $107 ~\mu \text{T}$ , the system bandwidth is 15 Hz at the laser power of 10 mW, and the magnetic field conversion coefficient is 16.88 V/T. Thus, this paper provides a new method to minimise the light source volume and integrate it with a NV magnetometer.

The development of practical applications of the magnetometer based on ensemble of nitrogen-vacancy centers has been impeded by the large size of the system. In this paper, we present an integrated and miniaturized magnetic field sensor with a volume of approximately 10 cm ³ . Compared to the previous design, with the fluorescence waveguide excitation and collection structure, both the optical excitation system and collection system are integrated into a compact device by combining the optical fiber, so that it can be a handheld sensing head. We demonstrated experimentally that this sensor head enables the optically detected magnetic resonance measurements with or without the external magnetic field. Subsequently, we verified that the magnetic-field sensitivity is approximately 67 , and projected the photon shot noise limited sensitivity to be 2.04 . This novel system has considerable performance regarding previous designs while greatly reducing dimensions.

Microstructure is important to the development of energy devices with high performance. In this work, a three-dimensional Si-based metal-insulator-metal (MIM) capacitor has been reported, which is fabricated by microelectromechanical systems (MEMS) technology. Area enlargement is achieved by forming deep trenches in a silicon substrate using the deep reactive ion etching method. The results indicate that an area of 2.45 × 10³ mm² can be realized in the deep trench structure with a high aspect ratio of 30:1. Subsequently, a dielectric Al₂O₃ layer and electrode W/TiN layers are deposited by atomic layer deposition. The obtained capacitor has superior performance, such as a high breakdown voltage (34.1 V), a moderate energy density (≥1.23 mJ/cm²) per unit planar area, a high breakdown electric field (6.1 ± 0.1 MV/cm), a low leakage current (10⁻⁷ A/cm² at 22.5 V), and a low quadratic voltage coefficient of capacitance (VCC) (≤63.1 ppm/V²). In addition, the device’s performance has been theoretically examined. The results show that the high energy supply and small leakage current can be attributed to the Poole–Frenkel emission in the high-field region and the trap-assisted tunneling in the low-field region. The reported capacitor has potential application as a secondary power supply.