Zhang Wenhui, Zhang Hao, Matsushima Kyoji, Jin Guofan
Opt Express. 2021 Mar 29;29(7):10089-10103. doi: 10.1364/OE.419096.
The shifted band-extended angular spectrum method (Shift-BEASM) is proposed to calculate free-space diffraction between two parallel planes with an off-axis offset. Off-axis numerical propagation is useful for simulating non-paraxial and large-scale fields. The proposed Shift-BEASM allow us to calculate the off-axis diffraction in a wide propagation range by extending the effective bandwidth using the nonuniform fast Fourier transform. The calculation accuracy is higher than that of existing techniques, such as the shifted-Fresnel method and shifted band-limited angular spectrum method, not only in the near field but also in the far field. Numerical examples and accuracy as well as theoretical formulation are presented to confirm validity of the proposed method.
提出了移位频带扩展角谱方法（Shift-BEASM）来计算两个具有离轴偏移的平行平面之间的自由空间衍射。离轴数值传播对于模拟非傍轴和大规模场很有用。所提出的Shift-BEASM通过使用非均匀快速傅里叶变换扩展有效带宽，使我们能够在很宽的传播范围内计算离轴衍射。该计算精度不仅在近场而且在远场都高于现有技术，如移位菲涅耳方法和移位带限角谱方法。给出了数值例子、精度以及理论公式，以证实所提方法的有效性。
