Fast nonparaxial scalar focal field calculations
2014
An efficient algorithm for calculating nonparaxial scalar field distributions in the focal region of a lens is discussed. The algorithm is based on fast Fourier transform implementations of the first Rayleigh–Sommerfeld diffraction integral and assumes that the input field at the pupil plane has a larger extent than the field in the focal region. A sampling grid is defined over a finite region in the output
planeand
referredto as a
tile. The input field is divided into multiple separate spatial regions of the size of the output
tile. Finally, the input
tilesare added coherently to form a summed
tile, which is propagated to the output plane. Since only a single
tileis propagated, there are significant reductions of computational load and memory requirements. This method is combined either with a subpixel sampling technique or with a chirp
z-transformto realize smaller sampling intervals in the output plane than in the input plane. For a given example the resulting methods enable a speedup of approximately 800× in comparison to the normal
angular spectrum method, while the memory requirements are reduced by more than 99%.
Keywords:
-
Correction
-
Source
-
Cite
-
Save
39
References
17
Citations
NaN
KQI