Peak Power Active - Active Transient Mode-locked Laser Technology

Pulsed lasers have been used widely in various fields, such as optical communication,medical treatment,materials processing and nonlinear optics. Technology of mode-locked laser is an efficient method to obtain high peak power pulse. Developing techniques for Q-switching or mode-locking laser has been made as a new exploration to get compact pulsed lasers. In this thesis, we discussed the properties about synchronous acoustic-optical mode-locking modulation, electro-optical Q-switching, cavity length modulate technology, single pulse selecting and researched frequency doubling technology with a novel method of active-active transient mode-locked pulsed laser.1. The output characteristic of the mode-locked laser was studied. From active and passive mode-locked principle set out, compare to these virtues and defects. Studied the exportation characteristic of continuous active mode-locking and active pulse mode-locking. Based on the most important request, the outside trigger to lighting time vibration is±15ns. Active-active mode-locked laser has been presented in this thesis.2. The influence to the output beam characteristic was studied with the cavity changing. Designed double triangular prism modulator whose accuracy is to 25μm. carried out the cavity changing fast and precisely without change the light direction. It is the foundation of that further research about the automatic cavity length modulator.3. Studied Q-switching process of mode-locked laser in detail, the electro-optical Q-switching principle and circuit were also studied. Carried on an improvement to the electro-optic Q-switch. The electro-optic Q-switch's quick trigger was free from interference with high voltage about 6000V. Studied the principle about the acoustic-optical modulator. The modulator's power which carried out 45W. Designed and improved water cold system, carried out water temperature variety not more than 0.05℃. Carried out active-active pulse mode-locked laser which is continuous work at 20Hz. the output wrap net energy was 6.30 mJ. and its variety less than 2% at 1064nm. 4. The process about single pulse selecting which was studied in detail. We used the double KD~*P single pulse selector, carried out single pulse selecting rate to 100%. single pulse energy attains 1.187mJ. the energy variety not more than 3%, the pulse width less than 300ps, the transient peak power is to 3.63×10~6W. The outside trigger to lighting time dithering is±15ns.5. The three stage laser amplification and the frequency doubling have been studied. Finally we gained an active-active mode-locking YAG laser with high stability and power density. A single pulse laser output peak power is 7×10~8W at 532nm wavelength; the KTP frequency doubling efficiency attains 60%; the BBO frequency doubling efficiency is to 40% and get the KTP damage threshold is 1.13 GW/cm~2. It have important reference value to carry on the best frequency doubling experiment about the nonlinear crystal KTP (1064 nm).