磁约束激光聚束性能及基础理论研究

Improving the high-bunching performance of laser is a key problem in the laser measuring and the laser manufacturing fields. An obvious phenomenon of position deflection, we discovered, will be presented in the magnetic field of a couple of Nd-Fe-B permanent magnet. For upon problem and phenomenon, a novel research method and theory, using restricted structure with high energy and mutually exclusive magnetic field to reduce the laser beam divergence and improve the laser bunching performance will be researched in this project. The influence of the amplitude and the frequency of the laser with particle nature acted by magnetic field restricted structure will be investigated, and the characteristics of the laser bunching parameters will be analyzed with the change of the magnetic field restricted structure. The varying rules of the twist-rotating angle, the amplitude and the phase of the polarized light are investigated, and the deflection mechanism of laser beam will be researched from the micro perspective based on the novel magneto-optic effect. Under the restriction of permanent magnetic field and electromagnetic field, the structure parameters of the magnetic field intensity, the magnetic tube dimension, and the magnetic pole number will be changed, and the relation between upon parameters, the laser beam divergence, and the laser flux density will be deduced. In addition, by rotating the magnetic field structure, an isotropy magnetic field is produced to investigate the relation among the laser bunching performance, rotating velocity, and magnetic field restricted structure. Then, a set of laser high-bunching performance theory and method under the mutually exclusive magnetic-confinement-effect will be developed, which will expand the theoretical category of magneto-optic effect.

高能束激光聚束性能的提高是激光测量、激光制造等领域发展的一个关键难题，课题组研究发现采用一对铷铁硼永磁体可使HeNe激光束产生明显的偏移现象，针对上述问题和发现，本课题首次提出利用高能互斥磁约束体改变激光聚束特性，提高聚束性能的研究方法和全新理念。对粒子性激光的振幅、频率变化受磁场约束体影响的规律和机理进行探索性研究，分析激光聚束参数在磁场约束体结构参数变化时的综合表征；研究单束偏振光在变化的磁约束场中旋偏角、幅值、相位参数的变化特性，从微观角度探索粒子性光束的磁光效应偏转机理；探索永磁、电磁互斥场约束下，改变磁场强度、磁腔尺度、磁极对数量等结构参数，建立激光发散角偏转量、光通密度、激光功率与约束体特性参数间的本构关系方程；旋转磁约束体，研究各向同性磁场下激光聚束性能参数与约束体转速、结构参数间的变化规律。建立一套互斥磁约束效应下的提高激光聚束性能的方法与理论，拓宽磁光效应的理论范畴。

目前很多新兴的激光技术领域，包括激光测量、激光制造、航空航天、船舶制造等领域，对于高聚束激光的要求已经异常迫切。为了实现激光高聚束，项目对永磁和电磁约束情况下低功率激光的传播特性进行了研究，分析激光束在磁约束作用下特征参数的变化规律。此外，项目还研究了典型溶液的激光旋偏特性，利用磁光偏转效应，实现了溶液典型特征参数的激光非侵入式检测。试验研究表明：永磁约束磁腔中心点的磁感应强度的调节范围为0.2277T~0.8243T，线偏振光偏振面旋转角的范围为13.6度~142.6度，磁感应强度从0.4563T增加到0.8243T时，引起了激光光斑直径的细微减小和激光功率的微弱增强；电磁约束磁腔中心点的磁感应强度的调节范围为0~0.1299 T，磁场强度较弱，激光光斑面积、功率、中心坐标等特征参数并没有表现出规律性的变化；典型溶液的激光旋偏特性研究实现了误差范围为-0.49%至1.15%的氯化钠溶液浓度测量，误差范围为-0.67%至0.44%的葡萄糖溶液浓度测量，误差范围为-0.79%至1.11%的氢氧化钠PH值测量，误差范围为-0.84%至0.44%的盐酸溶液PH值测量，测量系统不确定度为0.05°。项目的研究为工业制造等领域提供了一种激光高聚束实现方法，为需要控制溶液浓度等参数的工业生产领域提供了一种溶液典型参数的非侵入式光学测量方法。