ABCD Matrixes
are used in paraxial optical design.
The angles are measured in radians!
A beam is described by a distance r from the optical axis and a offset angle from the optical axis
An ABCD Matrix that describes the optical element is formed
The ABCD Matrix is multiplied by the input vector
The result is an output vector that describes the output beam with a new distance from the optical axis and a new angle off the optical axis
is a short for for the equation system
with
with
Examples of ABCD matrices for simple optical elements :
Where d = reduced distance= thickness / refraction index
Where d_i = reduced distance_i= thickness_i / refraction index_i
Where:
R = radius of curvature, for a convex surface (centre of curvature after interface)
= initial refractive index
= final refractive index
Identity matrix
Where:
effective radius of curvature in tangential plane (horizontal direction)
effective radius of curvature in the sagittal plane (vertical direction)
With for convex mirrors (centre of curvature after interface)
Where:
f = focal length of the lens, where for convex/positive/converging lenses. Valid if if and only if the focal length is much bigger than the thickness of the lens
Where:
= refractive index outside of the lens.
= refractive index of the lens itself (inside the lens).
= Radius of curvature of First surface.
= Radius of curvature of Second surface.
t = center thickness of lens.