An updated fast solution in modeling quasi-optical beam waveguides is reported, where several mirror reflectors are utilized for the beam transformation. The fast Fourier transform Poynting vector ray tracing between virtual apertures (FFT-PVVAs) algorithm has been introduced and applied in modeling the reflected beam, based on the FFT-accelerated beam propagator between parallel apertures, and the Poynting vector ray tracing for the mirror reflection. However, for designing and optimizing a beam path with multireflectors, it is desired that the accumulated precision loss due to the Poynting vector ray tracing can be further reduced. As a modification, angular spectrum transform-based beam propagator between oblique apertures is introduced, so as to reduce the ray tracing path length. The improved method is named as FFT-PVVA-tilted propagation (FFT-PVVA-TP). As validation, beam propagation in a four-mirror beam waveguide is simulated by FFT-PVVA, FFT-PVVA-TP, and physical optics integration. Numerical results suggest that FFT-PVVA-TP provides clearly better accuracy after four times of beam reflection.

中文翻译：

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带有倾斜 FFT 光束传播器的准光学光束波导的更新快速解决方案

报告了模拟准光学光束波导的更新快速解决方案，其中使用多个镜面反射器进行光束变换。基于平行孔径之间的FFT加速光束传播器和镜面反射的坡印廷矢量射线追踪，引入了虚拟孔径之间的快速傅里叶变换坡印廷矢量射线追踪（FFT-PVVA）算法并将其应用于反射光束的建模. 然而，为了设计和优化具有多反射器的光束路径，需要能够进一步减少由于坡印廷矢量光线追踪导致的累积精度损失。作为修改，引入了基于角谱变换的斜孔间光束传播器，以减少光线追踪路径长度。改进后的方法称为FFT-PVVA-倾斜传播（FFT-PVVA-TP）。作为验证，通过 FFT-PVVA、FFT-PVVA-TP 和物理光学集成来模拟四镜光束波导中的光束传播。数值结果表明，经过四次光束反射后，FFT-PVVA-TP 提供了明显更好的精度。