Near-Field Effects of Apodisation on Coherent Aberrated Optical Systems

摘要

The effects of Gaussian apodisation with -0.8 waves of spherical aberration on a coherent optical system was examined. The area of study was in the near field concentrating on the areas near the focus in the Fresnel region of an f/12 system using optical wavelengths. Computer predictions were made for four cases: unapodised-unaberrated, apodised-unaberrated, unapodised-aberrated, and apodised-aberrated. Predictions were made for cross sectional planes perpendicular to the optical axis using Fourier optics. Merdional plane predictions were produced using a numerical integration method of determining the Kirchoff integral. Additionally, experimental data are given to compare with the predictions. It is shown that the experimental data matches the computer predictions and that apodisation is an effective method for controlling the ringing due to edge effects and spherical aberrations. Additionally, fine structure corresponding to Young's double slit interference in unapodised cases.