基于激光冷却技术,理论研究了冷却光参数对镱原子永磁体塞曼减速器的影响。通过对冷却光的光强、有效系数进行计算分析,得到永磁体塞曼减速器的最佳长度。研究永磁体塞曼减速器磁场分布对冷却光偏振和失谐量的依赖关系,发现将塞曼捕获速度设为310 m/s时,若采用失谐量为-400 MHz的σ-光,永磁体塞曼减速器的磁场幅值可较小,此时原子在塞曼减速器末端更容易脱离共振减速过程。根据优化后的冷却光参数,本文结合磁偶极子模型,提出了适用于冷镱原子光晶格钟的横向磁场永磁体塞曼减速器,为星载钟以及可搬运光钟的发展奠定基础。

Experiments on developing a frequency-stabilized 555.8-nm laser are presented. The 555.8-nm laser is obtained by frequency doubling of a 1111.6-nm diode laser through single-passing a periodically poled lithium niobate (PPLN) waveguide. The 555.8-nm laser is then locked to a stable high-finesse Fabry–Perot (FP) cavity by the Pound–Drever–Hall (PDH) technique. The finesse of the cavity is measured by the heterodyne cavity ring-down spectroscopy technique. The linewidth of the 555.8-nm laser is investigated. After the laser is locked, the laser line width is reduced to about 3 kHz. This frequency-stabilized 555.8-nm laser is used in experiments on the laser cooling and trapping of ytterbium atoms to develop an ytterbium optical clock.

An injection-locked Ti:sapphire laser is developed, with injection locking achieved using the Pound-Drever-Hall technique. By measuring the dependence of output power on the pump power with various Ti:sapphire laser parameters, we experimentally studied the influences of the ring cavity length, the focal length of the pump-laser mode-matching lens, and the output–coupler transmission on the threshold and slope efficiency. The dependence of the output power on the master laser power is also investigated. The present study provides a guideline for developing a Ti:sapphire laser with high slope efficiency and low threshold.

High power second harmonic generation (SHG) in MgO-doped LiNbO3 waveguides is investigated using a three-dimensional (3D) coupled thermo-optical model. Simulations performed for a 1 111.6-nm fundamental laser show the influence of the absorptions and the thermally induced dephasing on the conversion efficiencies of the different waveguides. The onset of the thermally induced dephasing effect for each waveguide is also indicated. As a result of high light intensity in the waveguide, nonlinear absorptions are identified as the possible main factors in efficiency losses in specific cases.

Theoretical analyses are presented on the critically phase-matched second-harmonic generation (SHG) in a biaxial crystal with the focused fundamental Gaussian beams. The dependence of the second-harmonic light power on the phase matching conditions, focused geometries, walk-off effects, and absorptions are discussed in detail. Expressions are presented for calculating the light power of the types I and II SHGs in the biaxial crystal, applied to optimize the blue light generation with the LiB3O5 crystal. A maximum conversion efficiency of around 37% is obtained with 798-nm laser power of 500 mW.