Rapid and robust laser-frequency auto-locking is essential for the field deployment of quantum communications, quantum computing, and precision-measurement technologies; however, achieving this remains a considerable challenge. Here, we propose and demonstrate an auto-locking scheme employing Bayesian optimization and discrete biorthogonal wavelet transformation. First, the reference is rapidly sought by making intelligent use of historical observations, eliminating the inherent blindness of the traditional parameter-scanning method. Second, the frequency reference is robustly identified by pinpointing transition signals with the discrete biorthogonal wavelet transformation and analyzing their immutable frequency differences and relative magnitudes, which are determined by the inherent atomic structure and remain resistant to environmental disturbances. This proposed approach achieves a fivefold acceleration in reference searching compared to conventional scanning methods in the case where the laser frequency drifts far away from the reference. Crucially, it achieves an identification accuracy of more than 99.5

We propose and demonstrate a dynamical mirror compensation scheme to restore velocity immunity in a large-area dual-atom-interferometer gyroscope. In an ideal Mach-Zehnder configuration, the phase shift is inherently immune to atomic velocity, but this property is broken by the Earth's rotation via the Coriolis effect. We overcome this by actively rotating the Raman mirrors during the pulse sequence to cancel the time-dependent angular offset. The implementation relies on a decouplable calibration-compensation chain to remove rotation-induced time-dependent terms. The scheme is validated on a dual-atom-interferometer gyroscope with an interference area of 21.1 cm^2. After compensation, the phase's dependence on atomic velocity is reduced 40-fold, and the velocity contribution to scale-factor stability is evaluated to be 0.13 ppm. The sensor achieves a rotation sensitivity of 1.3×10^-8 rad/s/Hz^1/2 and a stability of 1.9×10^-10 rad/s at 4500 s integration, together with a common-mode noise rejection ratio of up to 459, demonstrated in a seismic event. This work removes a key obstacle to scale-factor stabilization in atom-interferometer gyroscopes and paves the way for their applications in inertial navigation and geophysics.

Due to the wide range of application prospects, the high-performance optoelectronic sensing system are crucial for supporting rapid societal progress. In this work, we propose and demonstrate an optoelectronic sensing system based on the on-board integration of a photodetector (PD) based on (In,Ga)N nanowires and an aqueous zinc-ion battery (AZIB) employing a polyaniline cathode successfully. The PD demonstrates distinct on-off switching characteristic under ultraviolet illumination and operates effectively in zero-bias (self-powered) mode. It can perform different logic gate operations, and its responsivity exhibits bias-dependent tunability. Furthermore, the AZIB demonstrates a coulombic efficiency of 99.55% at 1 mA cm-2. Notably, by integrating the voltage supplied by the AZIB to the external circuit with the bias voltage regulation of the PD, the responsivity of the PD can be enhanced by 264%, demonstrating the beneficial role of the AZIB integration in optimizing detection performance. This study provides a novel approach to construct the safe, low-cost and portable photoelectric sensing systems, which is conducive to broadening application scenarios in the field of photoelectric technology.

A dual-atom-interferometer gyroscope has high sensitivity for accurate rotation measurements because of its immunity to common-mode noise. However, a measurement error is induced as the common phase noise, e.g., vibration noise, increases. In this work, we demonstrated a real-time compensation (RTC) scheme to improve the accuracy of measurements of the differential phase in dual atom interferometers. The vibration noise was measured by two seismometers and its induced phase shift was fed back to the Raman lasers after this shift was calculated based on the sensitivity function of the atom interferometers. After the RTC module was applied, the interference signals obtained via the square modulation method were stabilized at their midfringe points, which caused the vibration-induced phase noise for each of the atom interferometers to decrease from 495 mrad to 165 mrad. The differential phase error obtained by the dual atom interferometers and two seismometers was reduced from 114.8 mrad to 49.6 mrad, which implies that the rotation measurement error was improved by a factor of 2.3. This work paves the way to accurately measuring the rotation signal and has promising applications in fields of precision measurements.

Inertial navigation systems (INSs) exhibit distinctive characteristics, such as long-duration operation, full autonomy, and exceptional covertness compared to other navigation systems. However, errors are accumulated over time due to operational principles and the limitations of sensors. To address this problem, this study theoretically explores a numerically simulated integrated inertial navigation system consisting of a single-axis cold atom interferometer gyroscope (CAIG) and a conventional inertial measurement unit (IMU). The system leverages the low bias and drift of the CAIG and the high sampling rate of the conventional IMU to obtain more accurate navigation information. Furthermore, an adaptive gradient ascent (AGA) method is proposed to estimate the variance of the measurement noise online for the Kalman filter. It was found that errors of latitude, longitude, and positioning are reduced by 43.9%, 32.6%, and 32.3% compared with the conventional IMU over 24 h. On this basis, errors from inertial sensor drift could be further reduced by the online Kalman filter.

Operating atom-interferometer gyroscopes outside a laboratory environment is challenging primarily owing to the instability of laser systems. To enhance the thermal stability of free-space laser systems, a compact laser system using fiber lasers and all-quartz-jointed optical modules was developed for a dual-atom-interferometer gyroscope. Millimeter-scale optical elements jointed on quartz plates with identical quartz supports, ensure laser power stability and facilitate component upgrades. The primary diode laser was locked to the modulation transfer spectrum of Rb atoms, and Raman lasers were phase-locked to the primary laser. Frequencies for repumping, blow-away, and detection lasers were adjusted with acousto-optic modulators. At room temperature, laser power fluctuation was under 1:1000, polarization extinction ratio exceeded 30 dB, frequency fluctuation was below 91 kHz, and phase noise reached to -100 dBc/Hz @ 1 kHz. The optical modules were tested at 5-50 degrees C and applied to a dual-atom-interferometer gyroscope. The fringe contrast was tested over the temperature range. The proposed system paves the way for promoting field applications of atom-interferometer sensors.

Atom interferometry shows high sensitivity for inertial measurements in the laboratory, but it faces difficulties in field applications because of a trade-off between sensitivity and size. Therefore, there is an urgent need to develop a small sensor with high resolution for measuring acceleration and rotation in inertial navigation applications. Presented here is a miniaturized inertial sensor capable of measuring acceleration and rotation simultaneously based on high-resolution dual atom interferometers. A sensor head is integrated within a volume of 100 l, in which the vacuum chambers are fabricated by bonding quartz-glass windows with epoxy resin. A photoelectric cabinet is composed of four 3U rack units by integrating optical modules and electronic units. Dual atom interference fringes with a contrast of 29% are observed, and the acceleration and rotation are measured simultaneously by extracting their phase shifts. By developing a temperature compensation method to eliminate phase drifts caused by the thermal deformation of the Raman mirrors and using wave vector reversal to eliminate the phase drifts independent of the direction of the wave vector, measurement resolutions of 40 ng at 518 s and 6.1 nrad/s at 10 880 s are achieved for acceleration and rotation, respectively, from Allan deviations.

Large momentum transfer (LMT) is a crucial technique for achieving high-precision atom interferometer inertial sensors. However, the transfer efficiency of multi-pulse sequences is limited by optical power variations, Doppler detunings, and other systematic effects in a Mach-Zehnder interferometer. In this study, we investigated the robustness of LMT atom interferometry using Raman adiabatic rapid passage (RARP). The results showed that the RARP pulses exhibited a high transfer efficiency and good robustness, and they were applied to the construction of an LMT atom interferometer with a momentum transfer up to 14 (h) over bark. In the case of 6 (h) over bark, the phase offset of the atom interferometer with RARP multi-pulse sequences had an 8.4-fold advantage in robustness over that with Raman multi-pulse sequences. These findings provide an efficient and practical approach for developing compact mobile inertial sensors with improved contrast and higher accuracy in dynamic environments.

Atom-interferometer gyroscopes have attracted much attention for their long-term stability and extremely low drift. For such high-precision instruments, self-calibration to achieve an absolute rotation measurement is critical. In this work, we propose and demonstrate the self-calibration of an atom-interferometer gyroscope. This calibration is realized by using the detuning of the laser frequency to control the atomic velocity, thus modulating the scale factor of the gyroscope. The modulation determines the order and the initial phase of the interference stripe, thus eliminating the ambiguity caused by the periodicity of the interferometric signal. This self-calibration method is validated through a measurement of the Earth's rotation rate, and a relative uncertainty of 162 ppm is achieved. Long-term stable and self-calibrated atom-interferometer gyroscopes have important applications in the fields of fundamental physics, geophysics, and long-time navigation.

Herein, we propose a scheme for developing a large -momentum -transfer atom interferometer based on the top -hat composite light pulse technique. Additionally, we analyze the contrast and phase noise using a theoretical model of the sensitivity function of the proposed atom interferometer. A top -hat composite light pulse is used to simulate calculations based on the atom interferometer. We confirm that compared with a Gaussian beam, a top -hat composite light pulse can improve the consistency of atom cloud transitions and increase the contrast of atom interference fringes. By designing symmetrical and reversed composite pulse sequences, the phase noise and vibration noise in the time interval and free evolution process of multipulse action can be suppressed. The numerical simulation results show that the sensitivity of the proposed atom interferometer using a top -hat composite light pulse increases by one order of magnitude compared with that using a Gaussian beam. Moreover, the proposed atom interferometer achieves satisfactory suppression of external technical noise.

Cold-atom interferometers have matured into a powerful tool for fundamental physics research, and they are currently moving from realizations in the laboratory to applications in the field. A radio frequency (RF) generator is an indispensable component of these devices for controlling lasers and manipulating atoms. In this work, we developed a compact RF generator for fast switching and sweeping the frequencies and amplitudes of atomic-interference pulse sequences. In this generator, multi-channel RF signals are generated using a field-programmable gate array (FPGA) to control eight direct digital synthesizers (DDSs). We further propose and demonstrate a method for pre-loading the parameters of all the RF pulse sequences to the DDS registers before their execution, which eliminates the need for data transfer between the FPGA and DDSs to change RF signals. This sharply decreases the frequency-switching time when the pulse sequences are running. Performance characterization showed that the generated RF signals achieve a 100 ns frequency-switching time and a 40 dB harmonic-rejection ratio. The generated RF pulse sequences were applied to a cold-atom-interferometer gyroscope, and the contrast of atomic interference fringes was found to reach 38%. This compact multi-channel generator with fast frequency/amplitude switching and/or sweeping capability will be beneficial for applications in field-portable atom interferometers.

由于原子干涉陀螺仪具有灵敏度高和长期稳定性好等特点,在惯性导航、精密测量、测地学等领域有着重要的应用前景,因此,研制高精度原子干涉陀螺仪具有重要的科学意义和应用价值,已成为当今研究的热点课题之一.首先综述了国内外原子干涉陀螺仪的研究进展和发展趋势.然后分析了广义相对论检验和惯性导航应用对原子干涉陀螺仪的需求,介绍了10余年来在原子干涉仪、萨格纳克效应和原子干涉陀螺仪方面取得的研究成果.最后讨论了原子干涉陀螺仪的优缺点,并展望了原子干涉陀螺仪的发展机遇及其在精密测量和惯性导航领域面临的挑战.

We report a Mach-Zehnder-type dual-atom-interferometer gyroscope with an interrogation arm of 40-cm length and the interference area up to $1.2\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{2}$. The precise angular alignment of the large-scale separated Raman lasers is demonstrated by seeking the phase intersection of Ramsey-$\mathrm{Bord}\stackrel{\ifmmode \acute{}\else \'{}\fi{}}{\mathrm{e}}$ interferometers after the gravity effect is compensated and by decoupling the velocity dependent cross-talk phase shifts, and applied to build the Mach-Zehnder atom interferometer. Then a compact inertial rotation sensor is realized based on dual large-area Mach-Zehnder atom interferometers by precisely aligning the large-scale separated Raman lasers, in which the coherence is well preserved and the common noise is differentially suppressed. The sensor presents a sensitivity of $1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ $\mathrm{rad}/\mathrm{s}/{\mathrm{Hz}}^{1/2}$, and a stability of $9.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\phantom{\rule{0.16em}{0ex}}\mathrm{rad}/\mathrm{s}$ at 23000 s. The absolute rotation measurement is carried out by adjusting the atomic velocity which corresponds to modulating the scale factor.

Nanosecond high voltage pulse generators are widely used in dielectric barrier discharge, plasma jet, corona discharge in water, et al. In this paper, a novel bipolar pulse adder with output parameters adjustable is proposed. Several full bridge units are connected in series, and the storage capacitor in each unit is charged individually by a high-frequency resonant power supply. The charging process is analyzed. The influence of balance windings on voltage difference between storage capacitors is also studied. The results show that voltage difference changes with switching frequency. Without the balance windings, voltage unbalance is small at the switching frequency from 20 to 30 kHz. Optic fibers, together with gate drivers, are used to drive the Insulated-Gate Bipolar Transistors (IGBTs). Each switch can be turned on or off independently to change the rise/falling time. Finally, a 6-stage prototype has been developed in laboratory, which can generate bipolar pulses with amplitude, repetition rate, pulse width, and rise/falling time adjustable independently.