Research On Pulse-prolong For TEA CO₂ Pulsed Laser And Its Acoustic Effect Induced In Water

In some new research areas, such as acoustic remote measurement induced by pulsed laser, long pulse TEA (Transversely Excited Atmospheric) CO₂ laser is playing more and more important role. For prolonging the pulse length of the the TEA laser, this thesis finished following works.Firstly, several technologies to prolong the pulse width of TEA CO₂ laser have been summarized. Among these technologies, it pay more attention on discussing the pulse-prolong method based on Pulser/Sustainer technology.Secondly, the influences of the gas components and pressure on the laser temporal waveform have been investigated, and the rules of how the working gas affecting the laser pulse width are revealed.Thirdly, the thesis studied the Pulse Formed Net(PFN) in detail, which is one of the most pivotal technologies in Pulser/Sustainer mode. A software named Capture and PSpice of ORCAD family was utilized to simulate the output of the voltage for several PFN circuits, and optimization was also carried out.Based on the theoretical results, the experimental studies about the effects of PFN circuits on the pulse width and output energy have been performed under the conditions of unchanging the basic structure of the laser of the lab. Also the waveforms of the voltage and current during laser discharge have also been measured simultaneously. It was found that under the condition of single discharge pump circuit, prolonging the pulse length is limited. Furthermore, it also suggested a feasible way to improve it.At last, using laser temporal waveforms with different lengths, the experiments on laser acoustics have been carried out. The influences of the pulse width on the acoustics characteristics, such as the peaks of acoustic frequency are revealed. It was found that the peaks of acoustic frequency increases with the decrease of the pulse width.