CODE V Coatings
The CODE V Coatings window moves a coating between TFStudio and CODE V. It reads a CODE V MULTILAYER (MUL) coating, either the .seq command file that enters the stack or the .mul file CODE V saves from it, and writes one side of the active design as a .seq file that CODE V runs to make the .mul. Import and export are on separate tabs in one row. What the last action did shows at the right-hand end of that row, beside a warning badge: on the Import tab it holds what was noted while reading the file, on the Export tab what the export noted about the preview.
Settings
Section titled “Settings”Open .seq or .mul (Import tab, in the panel on the left): reads a coating file. The panel then shows the incident medium and the substrate in the file, the wavelengths, the angles and the reference wavelength. Beside it are the file’s title and its layers from the incident medium to the substrate, with their thickness in nm and a lock on each layer CODE V holds fixed (code 100).
Import → front coating and Import → back coating (Import tab): the file’s layers replace the front or the back coating of the active design, and the design keeps its incident medium, exit medium and substrate; the file’s INC and SUB are shown, not applied. The materials the layers use go into a user catalog named CODE V and the file name. With no design selected there is nothing to import into, so both buttons are off, while Save to Coating Library… stays on.
Save to Coating Library… (Import tab): saves the stack into My coatings, through the same dialog as Save current coating… in the Coating Library. The saved coating lies between the file’s INC and SUB: an index of n 1 with no k is saved as Air, and any other index or MIC material as the material the import makes of it. Its layers are the ones Import → front coating puts on the design. The band starts at the span of the file’s analysis wavelengths, or at the band Optical Evaluation is set to when the file has one wavelength, and the angle at its first ANG. The materials are carried in the saved coating, so it works on a computer that never opened the file, and saving adds nothing to your material catalogs.
Side (Export tab): Front writes the design’s incident medium, the front coating and the substrate. Back writes the exit medium as the incident medium, then the back coating from the exit side to the substrate, then the substrate, because CODE V wants air as the incident medium and the glass as the substrate on either face of an element.
Title (TIT): the coating title, up to 80 characters. It starts as the design name.
File name (SAV): the name of the .mul file the last command of the .seq writes. Save .seq offers the .seq under the same name.
REF (nm): the reference wavelength written to REF. It starts at the design’s reference wavelength.
Analysis wavelengths, WL: from, to and step in nm, with the number of wavelengths shown beside them. CODE V takes up to 100, and a larger count is refused before anything is written.
Angles of incidence, ANG: up to five angles in the incident medium, each from 0 up to but not including 90 degrees, decimals allowed. An entry outside that range goes back to the angle the field held. The plus button adds one, the cross removes one.
Generate preview builds the file and shows it in full; Save .seq writes it. A design with a material that cannot be found on this computer cannot be exported until the material is replaced. With no design selected there is nothing to export, and the Export tab shows nothing but a request to open or create one.
How to read it
Section titled “How to read it”From a .seq file the import reads the stack entered in the MDA sub-option: PHT, TIT, WL, WLG, REF, ANG, INC, COA, GRO and END groups, SUB and the MIC catalog. The analysis, plot and optimization options and the file commands are passed over; any other command is skipped, and the warning badge names it. CODE V reads at most 21 values from one WL, MWL or EXT command or one MIC material line and ignores the rest, and the import keeps the first 21 the same way, with a warning. A .mul file is read as CODE V saved it, both the sample coatings that come with CODE V and the files CODE V 11.2 saves.
A file that writes its numbers with a decimal comma (403,03) imports with a warning. The import reads a comma between two digits as a decimal point, but CODE V does not read such a number, so the file does not run in CODE V as it is.
WLG builds its wavelengths the way CODE V does, in single precision, so a wavelength can sit slightly off the round value. The window shows the wavelengths and REF with only the digits that precision holds: WLG 400 800 10 shows as 400 to 799.9997 nm, and with no REF in the file the reference wavelength shows as 599.9998 nm.
A thickness entered in waves (PHT N) is converted to nm with the layer’s n at REF, or at the central analysis wavelength when the file has no REF, which is what CODE V takes then. An imported MIC material is tabulated over the span of its MWL points, the analysis wavelengths and REF, with n and k that follow CODE V 11.2’s interpolation of its table, between the MWL points and past them. When REF lies outside a MIC table that a layer entered in waves uses, a warning names the material.
The front coating takes the layers in the order the file lists them. The back coating takes them with the file’s first layer on the exit side and its last against the substrate, the order the export writes a back coating in. When Symmetric (back = front) is ticked, the back coating is the mirror of the front, so only Import → front coating is available.
A layer CODE V holds fixed (code 100) is imported locked. A layer coupled to others (code 1 to 99) is imported free, since TFStudio has no coupled layers, and the report says how many there were.
Importing the same file again uses its catalog, and a material the catalog already holds is kept as it is, edits included. Undo puts the coating back as it was before the import; the catalog and the materials added to it stay.
What CODE V accepts, from the MUL chapter of its help, and what the export does about each limit:
| Item | CODE V | On export |
|---|---|---|
| Layers | up to 1000 | refused above 1000 |
Analysis wavelengths, WL |
up to 100 | refused above 100; written at most 21 to a WL command, the most CODE V reads from one |
Angles, ANG |
up to 5 | the field holds five |
Points per MIC material, MWL |
up to 21 | a material is sampled at the analysis wavelengths; above 21, the points kept are added one at a time where CODE V’s own interpolation misses the material most, until it matches every wavelength to the 6 decimals written or 21 are kept, and a warning names the material |
| Material label | 6 characters | made from the material name, with a number added when two labels would be the same |
| Incident medium and substrate | n only | the k of an absorbing medium is dropped, with a warning |
| Thickness | physical nm (PHT Y) or waves at REF (PHT N) |
physical nm, PHT Y |
| Fixed layer | code 100 | a locked layer is written with 100, any other with 0 |
A material whose n and k do not change over the analysis wavelengths is written as a number on its COA line rather than as a MIC entry. k is written as a positive number. CODE V enters layers from the incident medium to the substrate, while the Design Editor numbers them from the substrate, so the Design Editor’s layer 1 is the last COA line of the file.
The file ends with SAV, so running it in CODE V writes the .mul that MLT attaches to a lens surface. Once the coating is on a lens surface, CODE V takes the substrate index from the lens, so SUB matters only inside MUL.
References
Section titled “References”- CODE V Multilayer Design Reference Manual, chapter “Multilayer Coating Design and Analysis (MUL)”: MDA Sub-Option for the commands and their limits, Technical Notes for the order of the media on each kind of surface.