High Peak Power And High Pulse Energy Nd:YAG Laser

With the development of optoelectronic reconnaissance and guidance technology, it is more and more important to use high peak power, high energy laser to damage the CCD and other optoelectronic detector in optoelectronic countermeasure field. To achieve the high peak power, high energy laser output, the multi-polar amplification technology is generally used after the Q-switched laser in domestic. It lead to the huge size, not suitable for mobile use.According to the Q-switch technology and optoelectronic countermeasure demand, several Q-switch technology were analyses in this thesis. Rotating mirror Q-switch single pump cavity laser was chosen at last, a pulse with higher peak power, narrower pulse width was detected. Some efforts has been done in this thesis:1. The structure of CCD and its hard and soft damage were introduced, the principle of CCD damage by many kinds of type laser was discussed. And the great practical meaning for single high peak power and high energy ns level pulse laser was discussed too.2.Based on the rotating Q-switch theory, the affected factors were analyses. And rotating mirror Q-switch system was designed, gold-plated aluminum alloy lens was driven by high-speed motor. The electrical motor and laser power supply was controlled by the computer. The delay time of various components were measured and analyses. The electrical motor starting position was calculated and adjusted accurately. The frequency and pulse width of the lamp-pumped pulse was adjustable at the software, also the proportion of pump pulse periodic time and rotating mirror periodic time. So that the rotating mirror position and lamp-pumped pulse was matched well;3. A high peak power, high energy laser pulse output was achieved, the pulse frequency was adjustable that lower than the rotate frequency. The best rotating speed-18000rm was fixed based on the pulse waveform. The highest peak power, the fewest small pulse was detected at the 0.3ms pump time, 70 percent of output-transmittance, 795mm resonant cavity length. The small pulse energy was about 10% of the total energy, and the main pulse energy was about 0.162J, pulse width was 40ns, peak power was 4.05Mw, the lamp pumping energy of single pulse was 70J.The high peak power, high energy pulse output was achieved. At 0.3ms lamp pumping time, the free-running 70J energy pulse can't be got to be Q-switched. For the serious accumulated time error, the joule energy level high repeat frequency pulse can't be detected. With the improvement of laser power supply and time accuracy, narrower pulse width, about 10J single pulse energy, even hundreds of megawatts peak power, hundreds of Hertz frequency giant pulse may be detected.