An off-axis parabolic mirror has the advantage of not having to obscure the input beam to access the image plane. ZEMAX can easily model any off-axis portion of a surface, parabolic or not. This tutorial will show you how to model an off-axis parabolic mirror. The concept shown here applies to any decentered surface and is not limited to off-axis parabolic mirrors.

We will model a commercially-available off-axis parabolic mirror. The goal of this exercise is to be able to tilt the mirror about the X axis at any point along the optical axis (Z axis). The specifications for the mirror, taken from the manufacturer's web site, are as following:

Off-axis distance = 150 mm
Focal length = 1000 mm
Component physical diameter = 203 mm
Back surface of the substrate is perpendicular to the optical axis




If you are not sure about any of the procedures used in this tutorial, please refer to the following articles first.

Designing A Singlet in ZEMAX 
How to Tilt and Decenter a Sequential Optical Component