215
3.3. Diffraction
Figure 3.14: Amplitude transfer function, round aperture, paraxial
approximation.
equal to the landing energy in the image plane of the real system.
In order for the confocal system to properly represent the real
system, we must account for aberrations and defocus. The geometrical aberrations of the real system depend on the coordinates
(x O , y O ) in the object plane, and the coordinates (x A , y A ) in the
aperture plane of the real system. For now, we assume the object
coordinates to be fixed, and the aperture coordinates to be variable. It follows that the coordinates (x G , y G ) of the ideal image
are fixed as well. We regard the coordinates (x I , y I ) in the image
plane to be variable. A cone of rays impinges on the image point,
where each ray in the cone intersects a unique point (x A , y A ) in the
aperture plane. This is true both in the real system and the equivalent confocal system. Each ray has a unique amount of aberration,
which is expressed as an incremental shift δV OI in optical path
length of the real system. The primary aberration is represented
3.3. Diffraction
Figure 3.14: Amplitude transfer function, round aperture, paraxial
approximation.
equal to the landing energy in the image plane of the real system.
In order for the confocal system to properly represent the real
system, we must account for aberrations and defocus. The geometrical aberrations of the real system depend on the coordinates
(x O , y O ) in the object plane, and the coordinates (x A , y A ) in the
aperture plane of the real system. For now, we assume the object
coordinates to be fixed, and the aperture coordinates to be variable. It follows that the coordinates (x G , y G ) of the ideal image
are fixed as well. We regard the coordinates (x I , y I ) in the image
plane to be variable. A cone of rays impinges on the image point,
where each ray in the cone intersects a unique point (x A , y A ) in the
aperture plane. This is true both in the real system and the equivalent confocal system. Each ray has a unique amount of aberration,
which is expressed as an incremental shift δV OI in optical path
length of the real system. The primary aberration is represented