Differential Detecting Research On Coherent Population Trapping Atomic Clocks And Magnetometers

Coherent population trapping (CPT) is a quantum interference effect, and it has an important application on atomic clocks and atomic magnetometers. The thesis mainly experimentally study on the differential detecting to improve the short term stability of the CPT atomic clocks and the sensitivity of the CPT atomic magnetometers. The study results are listed below:1. The σ+σ+-σ-σ- scheme is applied to the micro 87Rb cell that is used in chip scale atomic clocks (CSAC) to study the application potential of the σ+σ+-σ-σ-scheme in CSAC. The results indicate that this scheme can increase the effectiveness of the 87Rb atoms, and the contrast of the CPT signal is 3 times larger than the prevalent scheme.2. The polarization orthogonalizer which is using in the lin ⊥ lin scheme has been improved in the thesis. The results present that the size of the improved polarization orthogonalizer is smaller, and it is hoped to be used in CSAC to improve the short term stability of the CPT atomic clocks.3. The disadvantages of the lin‖lin scheme have been analyzed. The frequency of laser should be locked on the Fe=1 absorption line, and this absorption line amplitude is wake, so when the CPT amplitude exceeds the absorption line, the laser frequency is hard to be locked and the noise will increase.4. The CPT spectrum that is caused by two mutually bichromatic has been studied, and the CPT spectrum simultaneously contains the interference effect and optic rotation effect of CPT. In the experiment, we obtained the two mutually bichromatic by the improved polarization orthogonaliizer, set a fix phase difference between the two bichromatic, and differentially detected the CPT signal. The experimental results indicate that this scheme can improve the short term stability of the CPT clocks by 3 times.5. A CPT atomic magnetometer scheme which is based on differentially detecting the magneto-optic rotation effect of the CPT (DMOR-CPT scheme) has been proposed. The DMOR-CPT scheme uses linearly polarized bichromatic to interact with Rb atoms, and differentially detects the magneto-optic rotation signal caused by CPT. The experimental results indicate that DMOR-CPT scheme can improve the sensitivity of the CPT magnetometers by half an order, and increase the ability to detect the weak magnetic field. Because the setup of DMOR-CPT magnetometer is simple, it is hoped to realize miniature CPT magnetometers.