The eigenfrequency of a resonator plays a significant role in the operation of a cylindrical shell vibrating gyroscope, and trimming is aimed at eliminating the frequency split that is the difference of eigenfrequency between two work modes. In this paper, the effects on eigenfrequency under resonator-top trimming methods that trim the top of the resonator wall are investigated by simulation and experiments. Simulation results show that the eigenfrequency of the trimmed mode increases in the holes-trimming method, whereas it decreases in the grooves-trimming method. At the same time, the untrimmed modes decrease in both holes-trimming and grooves-trimming methods. Moreover, grooves-trimming is more efficient than holes-trimming, which indicates that grooves-trimming can be a primary trimming method, and holes-trimming can be a precision trimming method. The rigidity condition after grooves-trimming is also studied to explain the variation of eigenfrequency. A femtosecond laser is employed in the resonator trimming experiment by the precise ablation of the material. Experimental results are in agreement with the simulation results.

Cylindrical shell vibration gyroscope is a kind of solid wave gyroscope which uses the inertia effect of elastic wave to detect the rotation angular velocity. Precision dynamic balance is the key to improve the stability of gyro standing wave vibration. In this paper, precision dynamic mass-stiffness balancing along the working mode axis at the top of the resonator cup-wall is studied. The radial region of different trimming types and the variation of resonator natural frequency and frequency split with trimming hole depth are determined by simulation. The femtosecond laser precision trimming-ablation experiment verifies the simulation results. The experiment and simulation have good consistency. This study clearly clarifies the precision dynamic mass-stiffness balancing law of trimming along the working mode axis, which provides a guarantee for high efficiency and high precision trimming.

Rotational motion of the optically trapped particle is a topic of enduring interest, while the changes of angular velocity in one rotation period remain largely unexplored. Here, we proposed the optical gradient torque in the elliptic Gaussian beam, and the instantaneous angular velocities of alignment and fluctuant rotation of the trapped non-spherical particles are investigated for the first time. The fluctuant rotations of optically trapped particles are observed, and the angular velocity fluctuated twice per rotation period, which can be used to determine the shape of trapped particles. Meanwhile, a compact optical wrench is invented based on the alignment, and its torque is adjustable and is larger than the torque of a linearly polarized wrench with the same power. These results provide a foundation for precisely modelling the rotational dynamics of optically trapped particles, and the presented wrench is expected to be a simple and practical micro-manipulating tool.

Cylindrical vibratory gyroscope is a kind of mode-matched gyros, and the frequency split would affect its sensitivity significantly. Frequency tuning is a major method to decrease the split. In the process of frequency tuning, the natural frequency should be measured firstly, and the measurement error is one of the decisive factor of tuning accuracy. Due to the measurement error of frequency is Normal Distribution, its effects on frequency tuning are studied by theoretical and simulation analysis from the statistical aspect. Firstly, the influence of frequency splitting on gyro sensitivity is studied, which shows the importance of reducing frequency splitting. Then the effect of different measuring accuracy on the measured value is analyzed. Thirdly, the tuning error that caused by the measurement error is researched in the process of trimming, and the tuning error is derived by theoretical analysis. Simulation and experiment results under different measurement error exemplify the value of tuning error. Finally, the optimal measurement accuracy that ensures achieving tuning accuracy is discussed.

Laser Doppler measurement technology, due to its high precision, is widely applied in the field of vibration detection. However, traditional Doppler vibrometers generally suffer from complex structures and bulky size, which limit their application in confined spaces. To address this limitation, this paper proposes a Doppler heterodyne measurement method based on a slant-ended fiber. The end face of the fiber is ground to form a specific inclination angle, which causes the reflected light from the end face to be coupled into the cladding for propagation. This design effectively suppresses the interference signals caused by end-face reflection, thereby enabling single-fiber direct measurement of object vibration. A prototype of fiber-optic vibrometer was constructed, with a metallic cylindrical resonator serving as the test object. The signal demodulation process was carried out using the Arctan algorithm. The measurements indicate that the amplitude of the resonator ranges from 0.22 to 973.6 nm, with a nonlinear error of 0.68% and a resolution of 0.2 nm/mV. In comparison with commercial vibrometers, the relative error across the full range is maintained within ±4%. The all-fiber Doppler vibrometer developed in this study ensures high measurement accuracy while realizing the miniaturization of the optical probe, which has a diameter of only 2.5 mm. The device’s capabilities extend to applications such as aero-engine health monitoring, modal analysis of automotive components, and an optical microphone.

Optically levitated spinning particles demonstrate significant promise for inertial sensing, precision measurement, and quantum science. However, the levitation and rotation of micro-vaterite particles primarily rely on a single trapping laser beam, severely limiting both stability and rotational capability. Although dual-beam configurations can improve trapping stiffness, they have not yet achieved stable high-rate spinning of vaterite particles. In this work, two counter-propagating beams with opposite circular polarization have been used to levitate and drive 3.58-μm-diameter vaterite particles to high spin rates. Compared to single-beam traps, our approach achieves a two-order-of-magnitude improvement in translational oscillation frequency and spin rate under atmospheric conditions. It achieved 6-MHz rotation at a moderate pressure of 20 Pa without enhancing thermal motion at low pressures. Meanwhile, the orientation of the particle under varying pressure conditions was characterized, revealing a fivefold improvement in orientational stability. This work provides a stable platform for high-rate spinning of particles, with significant potential applications in sensing and physical research.