The Study On The Comparison Of Two (40)~Ca~+ Ion Optical Frequency Standards

Comparing to microwave atomic clock, optical frequency standards have better performances, and it is the trend of atomic frequency standards. How to evaluate performances of optical clock is a hot topic in the optical clock field and the evaluation is the only way of improving the optical frequency standards. Two 40Ca+ optical frequency standards are developed in our laboratory, and the frequency comparison of two optical clocks is studied for the improvement of 40Ca+ ion optical frequency standards. In the thesis, the main contents are categorized as follows:1. A new single 40Ca+ion optical frequency standard was setup, including the designing of the ion trap, the vacuum system and the magnetic shielding layer and so on. After the optimization of the single ion signal and magnetic field, the closed-loop locking of the optical frequency standard was realized.2. The 729 nm probing laser system was improved, with linewidth of 1 Hz and the instability of 2E-15 for 1-60 s.3. The two ion trap systems were optimized, and single ion can be trapped steadily. Especially for ion trap-1, the ion can stay in the trap for more than one mouth. The frequency comparison of two 40Ca+ion optical frequency standards was realized. The result shows that the instability of optical frequency standards reaches 1.6E-16 for 10000 s.4. The magic wavelengths were measured firstly in the ion system, and the result was one of the best by now. With the measured magic wavelength, the oscillator strength ratio was given. In addition, the correlation between the direction of the linear polarization laser and the magic wavelengths in Ca+ was preliminary studied, which gave the experimental basis for the study of atomic hyperfine structure.