There are really a number of different ways in which ZEMAX can be used to return the index of refraction of a particular material at a given wavelength.  The different methods are outlined in this article.

Under Analysis > Glass and Gradient Index is the Dispersion Diagram.

The dispersion diagram will plot the index of refraction of a selected glass as a function of the wavelength in microns.  The scaling of both the x and y axes are user definable:

The glass may be chosen from the pull down menu in the settings of this feature.  Only the glasses from the catalogs listed under the System > General dialog are included in the pull down list.  So, if you wish to plot the index of refraction as a function of wavelength for a glass, first make sure that the catalog which contains that glass is listed under the Glass Catalogs tab of the System > General dialog:

The text version of the Dispersion Diagram reports the numerical data in a two column format, and also lists the Temperature and Pressure for which the data is being reported:

The Dispersion Diagram is often useful, but if you would like to obtain the index data for your specific design wavelengths, there are other ways of achieving this.  Please advance to the next page to find out more.

The Reports menu in ZEMAX provides two different reports which may be used to return detailed index data.  Specifically, the Surface Data report (Reports > Surface Data) lists the index of refraction data for each design wavelength for the selected surface number.  In the case below, Surface 1 has a glass type of SK2, and the index for each of the design wavelengths is reported:

The Prescription Data Report (Reports > Prescription Data) on the other hand, will display index data at each wavelength for every surface in your design.

In addition to the reports, the index of refraction can be returned in the Merit Function Editor via the INDX operand.

The only input values for this operand are the surface number and wavelength.  And, as is the case for any optimization operand, this data is also then accessible with the ZEMAX Programming Language through the OPEV() or OPER() functions.

The exact index of refraction for a glass at any wavelength can be returned by ZEMAX in a number of different ways:

• The Dispersion Diagram – plots the index of refraction as a function of wavelength for any glass.
• Reports -  Both the Surface Data report and the Prescription Data report will calculate the index at each design wavelength.  The Prescription Data report shows the index data for all surfaces.
• The Merit Function – The INDX operand will return the index for any specified surface and wavelength.
• ZPL – The flexible OPEV() function can be used in a macro to call up the INDX operand calculation.

REFERENCES

ZEMAX Optical Design Program User’s Guide, ZEMAX Development Corporation