FFT-based simulation of the hologram-recording process for light-in-flight recording by holography

We propose a numerical simulation method of the hologram-recording process for light-in-flight recording by holography (LIF holography) based on fast Fourier transform (FFT) to improve the efficiency of the simulation. Because it is crucial to consider the difference in the optical-path length between the object and reference light pulses, we modify a point-spread function by considering the optical-path lengths of the object and reference light pulses and whether both pulses interfere with each other in LIF holography. The computational time was shortened by 5.5×10⁵ times for the 4,096×4,096 resolution of the hologram using the proposed method. We evaluate the proposed method by calculating the root mean square error (RMSE) of the reconstructed holographic images. The RMSEs were relatively small considering the effect of speckle noise; these results effectively demonstrate the validity of the proposed method. Moreover, we reconstruct the moving pictures of light pulse propagation from the hologram generated by the proposed method. We compare the simulation and experimental results, and succeed in qualitatively demonstrating the validity of the proposed method.