Sequential Systems

In sequential mode -ideal for imaging systems- ZEMAX supports several different types of sources to accurately model the optical system. Conventional point sources are available, and field points may be defined using angles, object heights, or image heights. ZEMAX also supports astigmatic and elliptical sources. These sources are used for modeling laser diode collimators and other types of lenses used with astigmatic sources.

Point sources are very useful in the design of imaging systems, because the detected image properties of a point source can be used to accurately describe many aspects of image quality. However, extended sources are very useful for visualising distortion (especially non-radial distortion), checking image orientation or polarity, colour separation, and for qualitatively illustrating overall system performance.

Arbitrary extended sources are also available. These sources are defined in two ways. In the first, a simple ASCII format is useful for making bar targets, letters, squares and other simple test shapes. The number of pixels is user defined, and the intensity can vary at each pixel.

For complex 24-bit colour object scenes, ZEMAX supports the standard Windows .BMP and .JPG formats. Scenes defined in either format may be used as sources for full Monte-Carlo ray-tracing, and the detected image may be viewed for any optical system, using user-defined detector properties. The image below shows a .bmp image, used as the object scene of a wide angle optical system. The barrel distortion can be clearly seen.

Once an extended source file is created, it can be scaled, rotated, inverted, and relocated to any position in the field of view.  Millions of rays can be traced to give an accurate picture of real system performance.

Non-Sequential Systems.

Non-sequential ray-tracing is ideal for illumination systems, stray light and any system where complex source models must be considered. ZEMAX has built-in source models for laser beams, filaments, laser diodes and many other sources. You can also use Radiant Source models, or write your own using either a data file or your own C-code. The example below shows a filament source inside a faceted parabolic reflector, with a flat mirror behind. Only a few rays are shown, for clarity.

Bitmap and .jpg files can also be used as sources in non-sequential systems. Here the same image as used earlier is used in a non-sequential ray-trace: