Spatial-partition fast Fourier transform beam propagation method

Abstract In this paper, a spatial-partition fast Fourier transform beam propagation method (FFT-BPM) is proposed. The theoretical analysis of this beam propagation method is carried out, and the necessary conditions for its accurate application are derived. Through high-accuracy and high-speed simulation of the propagation of light beam in the medium with large refractive index variation, the reliability of this method is demonstrated.