Research On Reconstruction Of Laser Beam Intensity Spatial-temporal Distribution From The Temperature Field Of The Target

During the interaction of laser with material, laser energy/power and intensity distribution on the target surface are the most basic parameters in estimating the output state of laser and analyzing the effect of interaction. The veracity of measuring the parameters is crucial to the development and application of laser. It is hard to measure these parameters, because high energy laser not only has large laser spot area, but also has high energy and power. With the development of laser technology, output of laser becomes higher and higher, although there are many methods to measure the parameters, it is difficult to meet the laser diagnostic. To obtain these parameters well and truly, in the mean time, avoiding destroying the detector and minishing the cost in running the laser, a method to measuring laser beam intensity spatial-temporal distribution was developed. The mechanism of heat exchange and reconstruction of laser beam intensity spatial-temporal distribution from the temperature field of the target were introduced. To validate the theory of reconstruction, the model was established, and eradiated with regular laser beam, the process of heat exchange was analyzed, the beam distribution was reconstructed with the program, and the arithmetic was optimized. The theory of infrared detection was introduced, and some crucial factors influencing infrared detection were analyzed. Some crucial parameters were measured on testing platform. According temperature distribution of on the target memorized with thermal imaging system during the target was eradiated, the distribution of laser beam intensity was reconstructed, and compared with the intensity acquired using exposal compensate method, the laser power on the target was calculated. Lastly, The summarization of this paper was given as well as some aspects which need to be improved.