Kozacki Tomasz, Falaggis Konstantinos
Appl Opt. 2016 Jul 1;55(19):5014-24. doi: 10.1364/AO.55.005014.
A recent Letter [Opt. Lett.40, 3420 (2015)OPLEDP0146-959210.1364/OL.40.003420] reported a modified angular spectrum method that uses a sampling scheme based on a compact space-bandwidth product representation. That technique is useful for focusing and defocusing propagation cases and is generalized here for the case of propagation between two defocus planes. The proposed method employs paraxial spherical phase factors and modified propagation kernels to reduce the size of the numerical space-bandwidth product needed for wave field calculations. A Wigner distribution analysis is carried out in order to ensure high accuracy of the calculations in the entire computational domain. This is achieved by analyzing the evolution of the generalized space-bandwidth product when passing through the propagation algorithm for various space-frequency constraints. The results allow the derivations of sampling criteria, and, despite this, also show that a small amount of space/frequency zero padding significantly extends the capability of the recently reported modified angular spectrum method. Simulations validate the high accuracy of that method and verify a computational and memory gain of more than two orders of magnitude when comparing this technique with the conventional angular spectrum method.
最近的一篇快报[《光学快报》40, 3420 (2015) OPLEDP0146 - 9592 10.1364/OL.40.003420]报道了一种改进的角谱方法，该方法使用基于紧凑空间带宽积表示的采样方案。该技术对于聚焦和散焦传播情况很有用，在此将其推广到两个散焦平面之间的传播情况。所提出的方法采用傍轴球面相位因子和改进的传播核来减小波场计算所需的数值空间带宽积的大小。进行了维格纳分布分析，以确保在整个计算域中计算的高精度。这是通过分析在各种空间频率约束下通过传播算法时广义空间带宽积的演变来实现的。结果允许推导采样标准，尽管如此，还表明少量的空间/频率零填充显著扩展了最近报道的改进角谱方法的能力。仿真验证了该方法的高精度，并验证了与传统角谱方法相比，该技术在计算和内存方面有超过两个数量级的提升。
