| Nowadays,hundreds picoseconds pulse of laser has been used into so many fields,such as:amplification of high power hundreds picoseconds’ s fiber,sparking by laser and so on.And it will be more and more useful appreciably,which needs the hundreds picoseconds pulse of laser to be promoted increasingly.Generally speaking,the method to achieve the pulse of laser is amplification of the pulse,which will waste a part of the energy and we couldn’t get a stable high power pulse.And then,someone find to use the stimulated Brillouin scattering(SBS) to get the hundreds picoseconds pulse of laser,because it can be carried out simply by a cheaper cost.And we can get a integrated pulse as phase conjugation can make up the wave-front distortion.But there are some problems that because of the mechanism of SBS we can’t stabilize the initial phase of the Stocks pulse which is produced in SBS.In this thesis,we need to study and discuss influence factor of the capability of SBS stimulated by the stationary wave,which is based on a thus theory:generally,SBS is stimulated by the unpitched sound,but when it is equiped a mirror behind the media pool,we can get a stationary wave.And then use the stationary wave to stimulate the SBS.Because the phase of the stationary wave is stable,the acoustic wave field is stable,thus,the pulse compressed by SBS is stable.There are three steps to research the problem.first,explain the phenomenon in theory,and show the equation that can be used into calculation,which is so called coupled wave equation of SBS stimulated by the stationary wave.Second,solve the coupled wave equation,and use the MATLAB to simulate the acoustic wave and Stocks wave to explore how a series of influence factor impact the pulse width of the Stocks wave and the energy conversion efficiency.Finally,do research to explore whether the simulation is matched the physical truth.Measure the stability of pulse width and research how the position of the mirror influences these index of stability. |
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