Multi-beam Pulse Coherent Light Based On Two Pulse Lasers And Related Application Studies

With the developments of ocean detection techniques,Brillouin lidar system has shown it great potential in ocean detection.In this paper,a series of basic theory and experiment based on the pulse coherent light has been done.In this work to obtain the pulse coherent light,Q-switched technique,injection- Seeding theory and SHG(Second Harmonic Generation) has been introduced,firstly. According to the condition of coherent light,to acquire the coherent light that same frequency,starting phase and polarization ,two pulse lasers must be combined.One solution is that uses the partial 1064nm infrared to get the 532nm green light through the SHG, another method is that introduces the 1064nm infrared of one laser into the amplifier of another laser,and this way can obtain the high power 532nm green light.Basing on the above works,some related application including the threshold and pump-amplified technique was researched.Threshold is an important parameter of SBS,however,the traditional definition of threshold is subjective,and the explanation which between the steady state SBS threshold and the medium length is unreasonable. In this dissertation, analysed the characteristic of SBS threshold under different conditions and redefined the SBS threshold.We also proposed a new method that through measuring the attenuation coefficient of water to survey the SBS threshold.After a series of academic analysis and experiments,we brought forward a new SBS laser lidar system based on the pump-amplified technique.In this system,double coherent light was adopted.We use another coherent laser beam to amplify the SBS signal in real time.This new method will amplify the weak SBS signal due to the long distance attenuation in the water.We figured out a series of technical problems,proven its feasibility,and succeeded in experiment for principle verification.