Major New Features
These features and many others are described in more detail below. The page numbers refer to
pages in version 3.1 of the "Guide to TFCalc".
Automatic Synthesis of Coating Designs. The powerful needle optimization method
has been extended using the "tunneling" method, which creates a sequence of optimal solutions
of increasing thickness. This solves two difficulties in using the needle optimization
method: (1) deciding what the initial design should be and (2) deciding what to do if the
design found by needle optimization is not good enough. Now it is possible to start with
a single thin layer, and TFCalc will create designs of increasing complexity. (See pages
36 and 51.)
Global Optimization Improvements. TFCalc's global search capability allows you to
find many designs that meet your requirements. By sorting and eliminating duplicate designs,
this feature is much easier to use now.
Multiple Environments. This feature will allow you to design a single coating which
will operate in multiple "environments." In TFCalc, an environment consists of illuminant,
incident medium, substrate, exit medium, and detector. This feature allows you to define
multiple environments and then to optimize a coating for all those environments. Examples:
(1) an anti-reflection coating which works for several substrates, (2) a filter for multiple
illuminants, and (3) coatings for birefringent substrates. (See pages 16 and 21.)
Calculate Complex Refractive Index (N and K). Given up to three files of reflectance
and/or transmittance data taken from a single layer of an unknown material, TFCalc will attempt
to find a dispersion formula that fits the data. There are currently 25 combinations of
dispersion formulas for N and K. (See pages 52-54.)
Drude Dispersion Formula. TFCalc now includes the Drude model for metals, which
describes how the complex refractive of metals varies with wavelength. It is also possible
to fit reflection and/or transmission data to the Drude formula. (See page 24.)
Complex Index in Variable Materials Window. In TFCalc, variable materials are materials
whose refractive index is allowed to vary during optimization. These materials now have an
extinction coefficient, k. One application of variable materials is to find the complex
refractive index of one or more unknown layers. (See pages 20 and 52.)
Added the Hartmann 2 dispersion formula, which is very similar to the Hartmann formula already
available in TFCalc.
- Fixed a problem in the color calculation in the "Compute Color from Data File" command.
The illuminant was always assumed to be WHITE. This problem did not affect the other color
calculations in TFCalc.
- Added the capability of scaling the monitoring chart so that it begins at a user-specified
value. If the user selects this feature, then the title of the monitor plot changes to
"Scaled ..." (See page 46.)
- Changed the monitor ratio range to 0.1-10.0.
- Allow the user to change the width of the Table window.
- Fixed the problem of some error messages not being displayed.
- Fixed problem in EFI plot when the substrate name is exactly 8 characters long.
- For PowerMacs, fixed problem when reading text files. This involved the "Compute Color
from Data File" and "Read Wavelength Targets from File" commands.
- For PowerMacs, fixed the problem of the Exp function overflowing when very thick absorbing
layers were used.