方形单元衍射光学阵列器件实现近圆形均匀焦斑

本文以方形激光输入、圆形均匀焦斑输出为例,分析比较了整体式和阵列式衍射光学器件获取圆形均匀焦斑的能力.通过在阵列式器件方形单元间附加线性相移来改变各子焦斑的相互位置、重叠区域,从而逼近于一定直径的近圆形均匀焦斑.该方法将二维问题转化为一维,减少计算量.采用基于爬山法与模拟退火法相结合的混合算法设计相位分布.结果表明了该方法的有效性,并具有获得任意形状均匀焦斑的灵活性。

SQUARE DIFFRACTIVE OPTICS ARRAY ELEMENT FOR QUASI CIRCULAR UNIFORM FOCAL SPOT

In this paper,by taking square laser input and circula uniform focal spot output as an example,the ability to generate such a focal spot by using unitary diffractive optics element (DOE) or DOE array is analyzed and compared.By adding linear phase shift among the square units of DOE array to change the relative position and overlapped area of every sub focal spot,quasi circular uniform focal spots with certain diameters are realized.Two dimensions are converted to one dimension to simplify the calculation.Hybrid algorithm based on hill climbing and stimulated annealing is utilized for phase design.Simulated results show the validity of this kind of method and the flexibility of obtaining any shape uniform focal spot.