Beam of yellow light split by reflection/transmission

The FreeSnell Thin-Film Optical Simulator

Current Version Released Terms
1c3 2020-02-20 GPL 3.0

FreeSnell is a program to compute optical properties of multilayer thin-film coatings.

FreeSnell is an application of the SCM Scheme implementation and the WB B-tree database package.


FreeSnell-1c3 is a minor release. Details at*checkout*/freesnell/freesnell/ChangeLog

x86 MS-Windows Installation

x86_64 GNU/Linux with RPM Installation

Unix (Including GNU/Linux) Installation

Viewing Graphs

FreeSnell generates (encapsulated) PostScript graphs for output. If you have ImageMagick and GhostScript installed, then FreeSnell will use the ImageMagick convert program to translate these .eps files to other graphics formats:

You can view the PostScript .eps files with GhostView (Unix gv) or GSview (MS-Windows).


To run FreeSnell in MS-Windows from the C:\Program Files\FreeSnell diretory, click on the FreeSnell desktop icon. In Unix, from the FreeSnell directory run scm.

You can then type expressions to the SCM interpreter. To run FreeSnell's regression suites type:

  (load "dielectric.scm")
  (load "metallic.scm")
  (load "granular.scm")
  (load "coherence.scm")
  (load "polyethylene.scm")

To exit SCM type (exit).


The validation source files are a good source for design examples.

Refractive Index Spectra.
Validation suite of dielectric filters; generated from "dielectric.scm".
Validation of metallic films; generated from "metallic.scm".
Gold Ruby Glass Validation of granular films; generated from "granular.scm".
How thick films work in FreeSnell; generated from "coherence.scm".
Characterizing Polyethylene; generated from "polyethylene.scm".

FreeSnell Development

Volunteer opportunities

Related Software

FreeSnell and SimRoof were originally written to support Radiative Cooling in Hot Humid Climates, which employs infrared-transparent cold mirror roof panels.

Another Free-Software thin-film program is OpenFilters:

OpenFilters offers multiple tools for the design and optimization of optical interference coatings, including refinement, the needle method, the step method, the Fourier transform method and multiband rugates. It has the ability to optimize a stack to match a target response.

Copyright © 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2015, 2020 Aubrey Jaffer

I am a guest and not a member of the MIT Computer Science and Artificial Intelligence Laboratory.  My actions and comments do not reflect in any way on MIT.
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