基于简单透镜列阵的可调焦激光均匀辐照光学系统研究

Study on a zooming optical system based on simple lens array used for laser uniform irradiation

本文对基于简单透镜列阵的大口径激光均匀辐照光学系统的调焦能力进行了研究,结果表明,改变透镜列阵与靶镜之间的距离即可方便地改变靶面上光斑的大小.文中详细分析了相关参数对调焦能力的影响,并在此基础上设计出一个实用的光学系统.用数值方法模拟了激光束通过光学系统后的传输,发现尺寸不同的靶面光斑具有基本一致的强度结构特征.定量地分析了光斑内部散斑间隔、调制对比度、顶部不均匀度及能量集中度等描述光斑均匀辐照质量的指标,并研究了它们随靶面离焦量的变化关系.

A zooming optical system based on a simple lens array used for uniform irradiation by a large-aperture laser is studied; and it can be shown that the size of target spot may be flexibly adjusted by changing the separation between the lens array and the focusing lens. How the choice of optical parameters will affect the zooming ability is analyzed, and a practical system is designed. Propagation of laser beam through the optical system is simulated numerically;results show that the spots in different size are similar in intensity structure. Speckle separation, modulation contrast, rms nonuniformity, and concentration ratio of the spot are quantified, and their variations are analyzed when the target is placed in different positions relative to the focal plane of the focusing lens.