Theory of speckles in diffractive optics and its application to beam shaping
Theory of speckles in diffractive optics and its application to beam shaping
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DOI：
10.1080/09500349608232814
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发表时间：
1996-07-01
影响因子：
1.3
通讯作者：
Wyrowski, F
中科院分区：
文献类型：
--
作者：
Aagedal, H;Schmid, M;Wyrowski, F
设计的衍射相位元件（DPEs）解决一般的光束整形问题，其中的信号波是指定的强度分布在一个连续的支持在一个有限的信号窗口被认为是。在这种情况下，由于散斑可能会出现严重的设计问题。在引入散斑的数学定义和描述之后，研究了信号波的相位对设计过程的影响。事实证明，根据应用，伪随机或球面相位应该被用作迭代设计过程的信号波的初始相位。由于其平滑性，球面相位在迭代过程中防止了散斑的发生，而伪随机相位伴随着散斑效应。对于球面相位的成像特性不理想的应用，提出了一种软编码方法，该方法显著减少了伪随机相位的散斑数目。对于散斑仍然存在的情况下，我们最终提出了一种方法来消除这些对。
The design of diffractive phase elements (DPEs) for solving the general beam shaping problem where the signal wave is specified by an intensity distribution on a continuous support in a finite signal window is considered. In this case serious design problems due to speckles may arise. After introducing a mathematical definition and description of speckles, the influence of the phase of the signal wave on the design process is examined. It turns out that depending on the application a pseudo-random or a spherical phase should be used as an initial phase of the signal wave for an iterative design procedure. Due to its smoothness the spherical phase prevents the occurrence of speckles during the iteration process whereas the pseudo-random phase is accompanied by speckle effects. For applications where the imaging properties of the spherical phase are undesirable, a soft coding method is presented which significantly reduces the number of speckles of the pseudo-random phase. For cases where speckles still remain we finally present an approach for removing these in pairs.