Abstract

Rotating film processes are used to produce the apodization Gaussian filters of the Gaussian Fresnel G = 0.5, 1, and 5. The focal shift theory as presented in Ref. ¹ has been verified by using these filters in different beam-truncation conditions. Results, presented in intensity charts and photographs, are compared to theoretical predictions along the axis and in various planes parallel to the geometrical focal plane. Encircled energy is also measured by placing circular pinholes of different radii in front of the detector which is centered on the axis. The results are similar to those reported in Ref. ². The principal maximum value of the encircled energy is not found in the geometrical focal plane; its position changes abruptly when the radius of the pinhole is varied.

© 1987 Optical Society of America