| NON-SEQUENTIAL COMPONENTS |
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| Non-sequential ray tracing refers to the ability to compute which object in a list of objects a ray strikes. Applications for non-sequential ray tracing include illumination systems, stray light control, ghost analysis in imaging systems, and general design of non-imaging optical systems. |
Non-sequential objects vs. surfaces |
| Traditionally, lens design programs that used surfaces for sequential ray tracing would implement non-sequential ray tracing using the same surface model; the rays would simply intersect surfaces out of sequence. However, real objects cannot be described by the surface paradigm. |
Accurate tracing of real objects requires the use of 3D solid models. When performing non-sequential ray tracing, ZEMAX uses solid models of optical components, and is not limited to tracing rays through surfaces. |
Also unlike traditional lens design programs, ZEMAX can split rays at interfaces into multiple rays, and trace the reflected, refracted, scattered, and diffracted rays simultaneously, with correct accounting for energy, polarization, BSDF scattering distributions, thin films, and multiple order diffraction. |
A non-sequential system model in ZEMAX consists of one or more sources, objects, and detectors. |
Sources |
| Many non-sequential sources are included with ZEMAX, and others may be user defined. See the previous section on sources for details. |
Objects |
| Each object in ZEMAX is a solid or a surface. Objects may be placed anywhere in global coordinates. Object positions and rotations may be linked; this makes it easy to define compound objects and then move the entire assembly as a unit. |
Non-sequential object types include: |
| Lenses |
Standard, aspheres, toroids, MEMS |
| Diffractives |
Binary, grating, holographic |
| Solid shapes |
Cylinders, ellipses, rectangles, CPC, user defined |
| Faceted objects |
Completely arbitrary solids or surfaces |
| Imported objects |
IGES, STEP, SAT, or STL formats |
| Fresnel lenses |
True Fresnel lenses with grooves |
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All objects may be reflective, refractive, or absorbing. There are no limits to the number of objects. Objects may be imported from CAD programs in IGES, STEP, SAT, or STL format or may be defined using a simple ASCII polygon object format used by ZEMAX. ZEMAX supports many more objects than what is listed here, and arbitrary objects may be easily defined. Objects may be placed inside one another or be placed together to form a compound solid. |
Detectors |
| Any faceted object may be a detector. There are also dedicated detector objects which display coherent or incoherent irradiance (power per area), or intensity (power per solid angle) as detected anywhere in the optical system. ZEMAX uses either radiometric units (watts) or photometric units (lumens, lux, phot, footcandle, others) for both sources and detectors. |
Ray Database |
| Ray data from any ray trace may be stored in a file. This ray data may be subsequently used in displaying the optical system, or for computing the data in any detector, without the need to trace all the rays again. The ray database also allows complex queries to be defined on the database to reduce the data down to a set of rays which meet some test. |
Prism library |
| ZEMAX includes a large library of predefined prisms. These objects may be scaled to any size, then placed anywhere. Most common prisms, such as right, dove, roof, penta, pechan, and many others are included. |
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