Many measurements on the time gain/loss of the atomic clocks orbiting the spinning Earth have been done.The time gain/loss of the atomic clocks orbiting the spinning Earth is called gravitomagnetic clock effects.Clock...Many measurements on the time gain/loss of the atomic clocks orbiting the spinning Earth have been done.The time gain/loss of the atomic clocks orbiting the spinning Earth is called gravitomagnetic clock effects.Clock effects have been well studied from the consideration of the relativity theory and the effects are thought to be relativistic sequels.However,no studies has been done from the physics of Newton and the electrodynamics of Maxwell.In this paper,we have studied clock effects from Newton-Maxwell consideration and have shown that clock effects could be considered as simple consequences of Newton’s physics and Maxwell’s electrodynamics.展开更多
For most pulsed atomic clocks, the Dick effect is one of the main limits to reach its frequency stability limitation due to quantum projection noise. In this paper, we measure the phase noise of the local oscillator i...For most pulsed atomic clocks, the Dick effect is one of the main limits to reach its frequency stability limitation due to quantum projection noise. In this paper, we measure the phase noise of the local oscillator in the Ramsey-CPT atomic clock and calculate the Dick effect induced Allan deviation based on a three-level atomic model, which is quite different from typical atomic clocks. We further present a detailed analysis of optimizing the sensitivity function and minimizing the Dick effect by interleaving lock. By optimizing the duty circle of laser pulses, average time during detection and optical intensity of laser beam, the Dick effect induced Allan deviation can be reduced to the level of 10 14.展开更多
In the microwave 199Hg＋ trapped-ion clock, the frequency instability degradation caused by the Dick effect is un- avoidable because of the periodical interrogating field. In this paper, the general expression of the ...In the microwave 199Hg＋ trapped-ion clock, the frequency instability degradation caused by the Dick effect is un- avoidable because of the periodical interrogating field. In this paper, the general expression of the sensitivity function g（t） to the frequency fluctuation of the interrogating field with Nπ-pulse （N is odd） is derived. According to the measured phase noise of the 40.5-GHz microwave synthesizer, the Dick-effect limited Allan deviation of our 199Hg＋ trapped-ion clock is worked out. The results indicate that the limited Allan deviations are about 1.75 ×10-13/√τ and 3.03 ×10-13/√τ respectively in the linear ion trap and in the two-segment extended linear ion trap under our present experimental parameters.展开更多
The Dick effect is an important factor limiting the frequency stability of sequentially-operating atomic frequency standards. Here we study the impact of the Dick effect in the integrating sphere cold atom clock （IS...The Dick effect is an important factor limiting the frequency stability of sequentially-operating atomic frequency standards. Here we study the impact of the Dick effect in the integrating sphere cold atom clock （ISCAC）. To reduce the impact of the Dick effect, a 5 MHz local oscillator with ultra-low phase noise is selected and a new microwave synthesizer is built in-house. Consequently, the phase noise of microwave signal is optimized. The contribution of the Dick effect is reduced to 2.5× 10^-13τ-1/2 （3- is the integrating time）. The frequency stability of 4.6 × 10-13τ-1/2 is achieved. The development of this optimization can promote the space applications of the compact ISCA C.展开更多
A method that obtains the Ramsey-coherent population trapping （CPT） spectrum with the Faraday effect is investi- gated. An experiment is implemented to detect the light polarization components generated from the Far...A method that obtains the Ramsey-coherent population trapping （CPT） spectrum with the Faraday effect is investi- gated. An experiment is implemented to detect the light polarization components generated from the Faraday effect. The experimental results agree with the theoretical calculations based on the Liouville equation. By comparing with the method without using the Faraday effect, the potential of this method for a CPT-based atomic clock is assessed. The results indicate that this method should improve the short-term frequency stability by several times.展开更多
文摘Many measurements on the time gain/loss of the atomic clocks orbiting the spinning Earth have been done.The time gain/loss of the atomic clocks orbiting the spinning Earth is called gravitomagnetic clock effects.Clock effects have been well studied from the consideration of the relativity theory and the effects are thought to be relativistic sequels.However,no studies has been done from the physics of Newton and the electrodynamics of Maxwell.In this paper,we have studied clock effects from Newton-Maxwell consideration and have shown that clock effects could be considered as simple consequences of Newton’s physics and Maxwell’s electrodynamics.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0302101)the Initiative Program of State Key Laboratory of Precision Measurement Technology and Instruments
文摘For most pulsed atomic clocks, the Dick effect is one of the main limits to reach its frequency stability limitation due to quantum projection noise. In this paper, we measure the phase noise of the local oscillator in the Ramsey-CPT atomic clock and calculate the Dick effect induced Allan deviation based on a three-level atomic model, which is quite different from typical atomic clocks. We further present a detailed analysis of optimizing the sensitivity function and minimizing the Dick effect by interleaving lock. By optimizing the duty circle of laser pulses, average time during detection and optical intensity of laser beam, the Dick effect induced Allan deviation can be reduced to the level of 10 14.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11074248 and 11474320)
文摘In the microwave 199Hg＋ trapped-ion clock, the frequency instability degradation caused by the Dick effect is un- avoidable because of the periodical interrogating field. In this paper, the general expression of the sensitivity function g（t） to the frequency fluctuation of the interrogating field with Nπ-pulse （N is odd） is derived. According to the measured phase noise of the 40.5-GHz microwave synthesizer, the Dick-effect limited Allan deviation of our 199Hg＋ trapped-ion clock is worked out. The results indicate that the limited Allan deviations are about 1.75 ×10-13/√τ and 3.03 ×10-13/√τ respectively in the linear ion trap and in the two-segment extended linear ion trap under our present experimental parameters.
基金Supported by the National Natural Science Foundation of China under Grant No 11604353the Youth Innovation Promotion Association of Chinese Academy of Sciences
文摘The Dick effect is an important factor limiting the frequency stability of sequentially-operating atomic frequency standards. Here we study the impact of the Dick effect in the integrating sphere cold atom clock （ISCAC）. To reduce the impact of the Dick effect, a 5 MHz local oscillator with ultra-low phase noise is selected and a new microwave synthesizer is built in-house. Consequently, the phase noise of microwave signal is optimized. The contribution of the Dick effect is reduced to 2.5× 10^-13τ-1/2 （3- is the integrating time）. The frequency stability of 4.6 × 10-13τ-1/2 is achieved. The development of this optimization can promote the space applications of the compact ISCA C.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304362 and 11204351)
文摘A method that obtains the Ramsey-coherent population trapping （CPT） spectrum with the Faraday effect is investi- gated. An experiment is implemented to detect the light polarization components generated from the Faraday effect. The experimental results agree with the theoretical calculations based on the Liouville equation. By comparing with the method without using the Faraday effect, the potential of this method for a CPT-based atomic clock is assessed. The results indicate that this method should improve the short-term frequency stability by several times.
