Research On Interaction Characteristics Of Low-power Laser In High Magnetic Field Based On Magneto-optical Medium

With the rapid development of laser nuclear fusion and the X-ray laser,many scholars are focusing on the technology of the absorption mechanism of laser,the laser-induced plasma,and the magneto-optic imaging.The study of laser bunching performance has been improved,however mostly in some aspects such as improvement of laser structure,composition of auxiliary optical devices.The requirements of high bunching laser have been extremely urgent in many research fields of laser technology,such as laser measurement,laser manufacturing,aerospace,and shipbuilding.The study of laser bunching method will directly determine the precision of laser cutting,laser welding,and the application category of laser measurement.This dissertation is supported by the National Natural Science Foundation of China,focusing on the interaction characteristics research of the low-power laser in high magnetic field based on the magneto-optical medium.The effect of high magnetic field on the polarization state of linear polarized light and the propagation characteristics of low power laser beam are studied.The effect of high magnetic field on the rotation angle of the linear polarized light,the barycenter coordinates,the sport area,and the power of laser beam are analyzed.The research contents of this paper are as follows:1)The experimental platform of magneto-optical interaction characteristics is designed equipping with the position adjustment of laser,the magnetic field intensity control of confining magnetic cavity,and the integration of sensor for measuring the laser propagation characteristic parameters.The innovated design of the permanent magnetic confinement cavity is used to control the internal magnetic induction intensity.2)The measurement and control system of the magneto-optical interaction characteristics is developed which meets the special needs of the test process.The software supplies many functions: the software control of measuring modules,the real time acquisition and display of the barycenter coordinates of laser spot,the image processing and the area calculation of laser spot,the automatic generation of test report,and the data storage.3)The rotation angle of the linear polarized light was researched in the experiment of polarized laser interacting with electromagnetic field and permanent magnetic field.Some experimental parameters,such as the current of the electromagnetic confining magnetic cavity,the magnetic cavity diameter of the permanent magnetic confining cavity,and the geometrical parameters of the magneto-optical medium,are modified.The range of the rotation angle is varied from 0.2 to 25.5 degree in the electromagnetic field,and varied from 13.6 to 142.6 degree in the permanent magnetic field.At the same time,the magnetic induction intensity is in the range of 0-0.1299 T in the electromagnetic confining magnetic cavity and in the range of 0.2277-0.8243 T in the permanent magnetic confining cavity.4)The propagation characteristic parameters of low power laser beam are studied in the experiment of electromagnetic and permanent magnetic bunching laser by changing the current,the magnetic cavity diameter of electromagnetic confining magnetic cavity,the magnetic cavity diameter,and the series magnetic pole number of permanent magnetic confining cavity.The trends of the laser propagation characteristic parameters caused by magnetic field are not obvious in the experiment of electromagnetic bunching laser.The results and the influencing factors are analyzed.There is a slight decrease of laser spot area and a little enhancement of laser power in the experiment of the permanent magnetic bunching laser,when the magnetic induction intensity increases from 0.4563 to 0.8243 T.