Development Of An Injection-locked Ti: Sapphire Laser And Its Application In Optical Lattice Clocks

A neutral ytterbium optical lattice clock is one species of the optical lattice clock, which may become the next generation of the time and frequency standard. The ytterbium atoms which are trapped in the optical lattice by the laser cooling techniques can provide the clock transition with the linewidth of several miliherz. And the theory predicts that the uncertainty achieves 10-18, which promotes the time and frequency standard to an unprecedented degree of accuracy.The sufficient depth of the lattice potential only can be produced by the high power laser due to the far off resonance property of the lattice beams. So there is the need of the high power, narrow linewidth, and low noise laser system served as the light source for the 3D ytterbium optical lattice, which makes the injection-locked Ti:sapphire laser as the best choice. The Ti:sapphire crystal owns the good mechanical, thermal and spectroscopy properties, which makes the output laser beam with the high power and perfect profile easily. But the range of fluorescence spectra of Ti:sapphire is wide, if one wants to realize the narrow single mode output, the mode selection components have to be employed in the laser cavity, which raises the intracavity loss and brings the high threshold and low slope efficiency. The injection-locked technique avoids such defects and makes the level of the laser noise down to the quantum limit. This research propose a comprehensive theory to analyze the output power of the injection-locked Ti:sapphire laser, which gives a detailed discussion about the influence of the key parameters of the laser cavity and crystal on the laser power. And it forms many results such as the cavity structure should be set at the edge of the stability region, there is an optimal product of the crystal length and absorption coefficient and there is an optimal transmission of the output coupler. Also we have employed the experiment optimized by this theory and obtained the result of 600mW output with 5W pump power, which is agreed with the calculations.In addition, the thermal lens effect should be considered under the high pump power region, but the reported experimental data shows no such influence appears with 15W pump power for Ti:sapphire laser. We employed another research with numerical analysis, finite element analysis and transmission matrix method to give a comprehensive understanding on the thermal lens effect in the injection-locked Ti:sapphire laser. This research quantified the thermal lens induced by the elasto-optical effect and end face bulging; quantified the influence of the thermal lens on the laser and pump beam; calculated the decrease of the lasing efficiency caused by the thermal lens. The results show that when the pump power exceeds 20W the output power of the Ti:sapphire laser will be seriously influenced by the thermal lens and the thermal lens induced by strain rises. All the methods we used here can be applied on other end pumped lasers.This thesis also gives the description of the basic cooled atom theory applied in Yb optical lattice clock, including the basic principle of Zeeman slower, magneto-optical trap (MOT), and optical lattice. There is also the discussion about the mathematic models of the injection locking and Pound-Drever-Hall techniques and the detailed discussion for the electronic techniques to realize the injection locking and some experimental results.