The spin-exchange relaxation-free atomic gyroscope,with its exceptionally high theoretical precision,demonstrates immense potential to become the next-generation strategic-grade gyroscope.However,due to technological ...The spin-exchange relaxation-free atomic gyroscope,with its exceptionally high theoretical precision,demonstrates immense potential to become the next-generation strategic-grade gyroscope.However,due to technological noise,there is still a significant gap between its actual precision and theoretical precision.This study identifies the key factor limiting the precision of the SERF gyroscope as coupling noise.By optimizing the detection loop structure,a distinction between the dual-axis signals'response to optical and magnetic fields was achieved-where the optical errors responded similarly,while the response to magnetic noise was opposite.Based on the differences in the optical-magnetic response of the dual-axis signals,empirical mode decomposition was used to decompose the dual-axis gyroscope signals into multiple intrinsic mode functions,and Allan deviation analysis was applied to analyze the noise characteristics of the intrinsic mode functions over various periods.This study successfully reveals that optical errors caused by thermal-optical coupling and long-period magnetic noise induced by thermal-magnetic coupling are the dominant factors limiting the long-term stability of the SERF gyroscope.Based on these analyses,the study concludes that to achieve strategic-grade precision for the SERF gyroscope,it is essential to effectively address the noise issues caused by multi-physical field couplings.展开更多
We explore the impact of pumping beams with different transverse intensity profiles on the performance of the spinexchange relaxation-free(SERF) atomic magnetometers(AMs). We conduct experiments comparing the traditio...We explore the impact of pumping beams with different transverse intensity profiles on the performance of the spinexchange relaxation-free(SERF) atomic magnetometers(AMs). We conduct experiments comparing the traditional Gaussian optically-pumped AM with that utilizing the flat-top optically-pumped(FTOP) method. Our findings reveal that the FTOP-based approach outperforms the conventional method, exhibiting a larger response, a narrower magnetic resonance linewidth, and a superior low-frequency noise performance. Specifically, the use of FTOP method leads to a 16% enhancement in average sensitivity within 1 Hz–30 Hz frequency range. Our research emphasizes the significance of achieving transverse polarization uniformity in AMs, providing insights for future optimization efforts and sensitivity improvements in miniaturized magnetometers.展开更多
SERF陀螺仪工作在无自旋交换弛豫(SERF)状态下,电子自旋和核子自旋强烈耦合。通过研究电子自旋与核子自旋的耦合方程,分析了泵浦激光的功率和气室温度对SERF陀螺仪磁场补偿的影响,并搭建了SERF陀螺仪实验平台系统进行验证。研究结果表明...SERF陀螺仪工作在无自旋交换弛豫(SERF)状态下,电子自旋和核子自旋强烈耦合。通过研究电子自旋与核子自旋的耦合方程,分析了泵浦激光的功率和气室温度对SERF陀螺仪磁场补偿的影响,并搭建了SERF陀螺仪实验平台系统进行验证。研究结果表明:原子核自旋补偿磁场正比于泵浦激光功率,泵浦激光功率在9.7 m W至105.6 m W的变化范围中,自旋补偿磁场的变化达到8.9 n T;气室温度在107.5℃至149.3℃变化范围中,自旋补偿磁场变化为4.5 n T,无明显的相关性,并且相对于气室温度的变化,补偿磁场对泵浦激光功率变化更加敏感。展开更多
Since 1959, the freed serfs in Tibet have experienced tremendous improvements,reflected with changes in the family of the82-year-old Dawa.Dawa lives in the Khezang Village of Lhoka City in the Tibet Autonomous Region ...Since 1959, the freed serfs in Tibet have experienced tremendous improvements,reflected with changes in the family of the82-year-old Dawa.Dawa lives in the Khezang Village of Lhoka City in the Tibet Autonomous Region and is one of the few former Tibetan serfs still alive today in the region.Tibet practiced feudal serf system until 1959, and about one million serfs were freed since then.展开更多
March 28 of this year is the second Tibetan Serfs Emancipation Day. People of all nationalities in Tibet marked the day by hoisting the national flag and by singing and dancing. Smiles were on every face and a festive...March 28 of this year is the second Tibetan Serfs Emancipation Day. People of all nationalities in Tibet marked the day by hoisting the national flag and by singing and dancing. Smiles were on every face and a festive atmosphere pervaded the snowcovered plateau region.展开更多
In old Tibet, the local government (including individual officials), monasteries and feudal lords all engaged in trade. Without exception, they also lent money at usurious rates. Interest-based profits were a major so...In old Tibet, the local government (including individual officials), monasteries and feudal lords all engaged in trade. Without exception, they also lent money at usurious rates. Interest-based profits were a major source of their incomes. To exploit serfs, the Dalai Lama and the Tibetan local government established special agencies to handle money-lending matters. The agency established by the Dalai Lama for the purpose was called展开更多
Fifty years ago, on March 28, 1959, Zhou Enlai, Premier of the State Council of the People＇s Repubfic of China, promulgated a decree of the State Council, declanng the Tibet local government controlled by Tibet＇s fe...Fifty years ago, on March 28, 1959, Zhou Enlai, Premier of the State Council of the People＇s Repubfic of China, promulgated a decree of the State Council, declanng the Tibet local government controlled by Tibet＇s feudal aristocrats and upperstratum clergy dissolved on that day and resolving that the powers of the Tibet local government be exercised by the Preparatory Committee for the Founding of the Tibet Autonomous Region from that day on. This decision of great historic significance sounded the death knell of the feudal serf system in old Tibet, a theocratic system that was reactionary, corrupt and dark. The change of government cleared obstacles and created conditions for development and progress in Tibet. After that a broad democratic reform movement swept the plateau region. Under the leadership of the Communist Party of China, the one million serfs in Tibet buried the feudal serf system and won their emancipation,展开更多
基金supported by Hefei National Laboratory,Innovation Program for Quantum Science and Technology(2021ZD0300400/2021ZD0300402)the Beijing Natural Science Foundation(3252013)the China Postdoctoral Science Foundation(2024T171116).
文摘The spin-exchange relaxation-free atomic gyroscope,with its exceptionally high theoretical precision,demonstrates immense potential to become the next-generation strategic-grade gyroscope.However,due to technological noise,there is still a significant gap between its actual precision and theoretical precision.This study identifies the key factor limiting the precision of the SERF gyroscope as coupling noise.By optimizing the detection loop structure,a distinction between the dual-axis signals'response to optical and magnetic fields was achieved-where the optical errors responded similarly,while the response to magnetic noise was opposite.Based on the differences in the optical-magnetic response of the dual-axis signals,empirical mode decomposition was used to decompose the dual-axis gyroscope signals into multiple intrinsic mode functions,and Allan deviation analysis was applied to analyze the noise characteristics of the intrinsic mode functions over various periods.This study successfully reveals that optical errors caused by thermal-optical coupling and long-period magnetic noise induced by thermal-magnetic coupling are the dominant factors limiting the long-term stability of the SERF gyroscope.Based on these analyses,the study concludes that to achieve strategic-grade precision for the SERF gyroscope,it is essential to effectively address the noise issues caused by multi-physical field couplings.
基金Project supported by the National Natural Science Foundation of China (Grant No. 62303029)the China Postdoctoral Science Foundation (Grant No. 2022M720364)the Innovation Program for Quantum Science and Technology (Grant Nos. 2021ZD0300500 and 2021ZD0300503)。
文摘We explore the impact of pumping beams with different transverse intensity profiles on the performance of the spinexchange relaxation-free(SERF) atomic magnetometers(AMs). We conduct experiments comparing the traditional Gaussian optically-pumped AM with that utilizing the flat-top optically-pumped(FTOP) method. Our findings reveal that the FTOP-based approach outperforms the conventional method, exhibiting a larger response, a narrower magnetic resonance linewidth, and a superior low-frequency noise performance. Specifically, the use of FTOP method leads to a 16% enhancement in average sensitivity within 1 Hz–30 Hz frequency range. Our research emphasizes the significance of achieving transverse polarization uniformity in AMs, providing insights for future optimization efforts and sensitivity improvements in miniaturized magnetometers.
文摘SERF陀螺仪工作在无自旋交换弛豫(SERF)状态下,电子自旋和核子自旋强烈耦合。通过研究电子自旋与核子自旋的耦合方程,分析了泵浦激光的功率和气室温度对SERF陀螺仪磁场补偿的影响,并搭建了SERF陀螺仪实验平台系统进行验证。研究结果表明:原子核自旋补偿磁场正比于泵浦激光功率,泵浦激光功率在9.7 m W至105.6 m W的变化范围中,自旋补偿磁场的变化达到8.9 n T;气室温度在107.5℃至149.3℃变化范围中,自旋补偿磁场变化为4.5 n T,无明显的相关性,并且相对于气室温度的变化,补偿磁场对泵浦激光功率变化更加敏感。
文摘Since 1959, the freed serfs in Tibet have experienced tremendous improvements,reflected with changes in the family of the82-year-old Dawa.Dawa lives in the Khezang Village of Lhoka City in the Tibet Autonomous Region and is one of the few former Tibetan serfs still alive today in the region.Tibet practiced feudal serf system until 1959, and about one million serfs were freed since then.
文摘March 28 of this year is the second Tibetan Serfs Emancipation Day. People of all nationalities in Tibet marked the day by hoisting the national flag and by singing and dancing. Smiles were on every face and a festive atmosphere pervaded the snowcovered plateau region.
文摘In old Tibet, the local government (including individual officials), monasteries and feudal lords all engaged in trade. Without exception, they also lent money at usurious rates. Interest-based profits were a major source of their incomes. To exploit serfs, the Dalai Lama and the Tibetan local government established special agencies to handle money-lending matters. The agency established by the Dalai Lama for the purpose was called
文摘Fifty years ago, on March 28, 1959, Zhou Enlai, Premier of the State Council of the People＇s Repubfic of China, promulgated a decree of the State Council, declanng the Tibet local government controlled by Tibet＇s feudal aristocrats and upperstratum clergy dissolved on that day and resolving that the powers of the Tibet local government be exercised by the Preparatory Committee for the Founding of the Tibet Autonomous Region from that day on. This decision of great historic significance sounded the death knell of the feudal serf system in old Tibet, a theocratic system that was reactionary, corrupt and dark. The change of government cleared obstacles and created conditions for development and progress in Tibet. After that a broad democratic reform movement swept the plateau region. Under the leadership of the Communist Party of China, the one million serfs in Tibet buried the feudal serf system and won their emancipation,
