SQUARE DIFFRACTIVE OPTICS ARRAY ELEMENT FOR QUASI CIRCULAR UNIFORM FOCAL SPOT
方形单元衍射光学阵列器件实现近圆形均匀焦斑

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.