Gradient 6

This surface has the same shape as the Standard surface, with media whose index of refraction is described by

The n_x values are computed from the following formula:

with identical expressions (but different values for A, B, C, and D) for n₀ , n₁ , n₂ , n₃ uses nanometers rather than micrometers for λ.

The dispersion data is user defined and is stored in an ASCII file called GLC.DAT. This file is stored in the folder <glass> (see "Folders"). The first line in the file is a file version format specifier of the form:

 
VERSION N

where N is the version number of the file format, currently 1. OpticStudio will read older GLC data files that omitted the version number, however the current version number and format should be used for any new files created or data added. The remaining lines are blocks of 21 lines defining the name and data for each material in the form:

 
NAME A0
B0
C0
D0
A1
B1
etc... ending with D4

The first line in the block is the name of the material, which can be any name (without special characters such as spaces or quotes) less than 10 characters long. The next 20 lines are the values for A, B, C, and D for n₀ through n₄, respectively. There are no blank lines or comments allowed. OpticStudio can read in data for up to 25 different materials in the GLC.DAT file.

The dispersion data in the supplied GLC.DAT file was provided by the Gradient Lens Corporation (GLC) in Rochester, NY, (716) 235-2620. Contact GLC for detailed information on material properties. Not all of the materials offered by GLC are included in the GLC.DAT file. The following materials are included: ARS10, ARS20, ARS27, and ARS31.

To use the Gradient 6 surface materials, change the surface type to Gradient 6, and then enter the appropriate material name in the glass column of the Lens Data Editor.

The maximum step size Δt determines the trade-off between ray tracing speed and accuracy. For details see "Discussion on maximum step size for GRIN surfaces". Also see "Restrictions on surfaces following GRIN surfaces".

PARAMETER DEFINITIONS FOR GRADIENT 6 SURFACES


Parameter #	Definition
1	Δt

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Gradient 7