A while ago, I was reading through Joe Geary’s excellent book, “Introduction to Lens Design” 1, and it occurred to me that his first order construction of a Cassegrain telescope could be very easily written up as a BASIC script in FRED. The example file that...
Read MoreThis knowledge base article describes how to use a bitmap image as an emitter in FRED using the Detailed Source construct. An example system is included that demonstrates a bitmap source being imaged by an ideal 1:1 relay lens. The example image is included in...
Read MoreSetting up a source as a lambertian emitter can be easily done in FRED using the Detailed Source model but often ends up being inefficient for raytracing because the collection optics subtend a small solid angle compared to the emission of the source. Often, however,...
Read MoreThe attached FRED file contains three sampled spectra, one each for the x, y and z color matching functions. All three spectra can be selected on the tree simultaneously and the Plot option can be selected from the right mouse click context menu so that...
Read MoreThis knowledge base example demonstrates how to create a hemisphere volume emitter. Detailed source models allow for volume emitters in the shape of spheres, cylinders and boxes but no default functionality for hemispheres. The approach for creating a hemisphere volume emitter is a hybrid of...
Read MoreThis knowledge base article discusses how to use FRED to accurately model the coupling from a ball-lens capped semiconductor laser diode to a single mode fiber – an optical system common in optical fiber communication applications. This model demonstrates FRED’s capability to propagate coherent fields,...
Read MoreThis knowledge base article demonstrates an example of how to automate an analysis of which is dependent on a source’s wavelength specification. The setup is a ray bundle incident on a linear grating at some non-zero angle. The diffracted beam reflects from the grating and...
Read MoreThis knowledge base article describes a script that generates a FRED source that models the properties of solar light incident on a tilted or solar-tracking surface. The calculations are based on the National Renewable Energy Laboratory (NREL) “Bird Simple Spectral Model”. The model, created by...
Read MoreThis knowledge base article discusses how to use FRED’s digitization tool with polar data. A typical application would be to specify ray directions for a source using an intensity profile from a specification sheet. When available it is preferable to use a rayset in place...
Read MoreCoherent sources are represented in FRED using a superposition of Gaussian beamlets. The ray grid spacing of the source is used to determine the waist and divergence of the beamlets. To properly model coherent propagation properties, the beamlets must remain Gaussian and perform best when...
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