单缝衍射虚拟实验的激光测量数值模拟

Numerical simulation of laser measurement in the virtual experiment of single-slit diffraction

为了在激光单缝衍射虚拟实验中获得准确的光强分布与缝宽数值,同时探究影响实验结果精度的关键因素,对单缝衍射虚拟实验激光测量过程进行数值模拟。分析基模激光光束在衍射平面上光强和相位的不均匀性,及其对单缝衍射光强分布的影响,利用透镜将激光按照匹配要求输入到激光处理器中,设计一种双透镜架构方案降低单缝衍射实验偏差;采用菲涅耳—基尔霍夫衍射积分方程,推算接收屏内的光强极大与极小处固定关系,获取缝宽计算公式;将面元当作线元,利用积分运算与离散处理得到光振动解析式,通过衍射角改变模式获得接收屏内的光强分布图,完成实验全部过程。经过数值模拟计算可知,激光单缝衍射实验的衍射图像由喇叭口衍射和单缝衍射共同组成,实验光强分布图像左右峰值相同,证明推导过程具备较好可靠性,可为光学实验教学提供理论参考。

In order to obtain the accurate values of light intensity distribution and slit width in the virtual experiment of laser single slit diffraction and to explore the key factors affecting the accuracy of the experimental results,the laser measurement process of the virtual experiment of single-slit diffraction is simulated.This paper analyses the influence of the nonuniformity of the intensity and phase of the fundamental mode laser beam on the intensity distribution of the single-slit diffraction.We use the lens to input the laser into the laser processor according to the requirements,designed a double lens structure scheme to reduce the experimental deviation of the single-slit diffraction.Adopting the Fresnel Kirchhoff diffraction integral equation calculates the maximum and minimum intensity fixed in the receiving screen.The plane element is regarded as the line element.The analytical expression of light vibration is obtained by integral operation,discrete processing,and the light intensity distribution in the receiving screen is obtained by changing the diffraction angle mode,which completes the whole process of the experiment.Through numerical simulation,it can be seen that the diffraction image of the laser single slit diffraction experiment is composed of bell mouth diffraction and single slit diffraction.The left and right peaks of the experimental light intensity distribution image are the same,which proves that the derivation process in this paper has good reliability and can provide theoretical reference for optical experiment teaching.