When launching in execution a STRAT V6.2 program, this program does not allocate memory for the optical coatings. The program contains only functions (tools) that operate on coatings, not optical coatings (a reason for which after launching, the most of menu commands are not active - they have not objects on which they can act). The creation and the definition of the optical coatings are done in more phases.
The firs action is to give the command Create (or Create branch), by means of which a memory area is allocated for defining an optical coating. This memory area does not contain all the data that define an optical coating. It is intended for general data about a coating, such as: coating name, polarization status of incidence radiation, directories, save file name, etc. as well as a memory area necessary for connecting it to some other memory areas dynamically allocated such as: layers parameters, groups parameters, optimization targets, optical materials, structures describing an optical coating, evaporation geometry, etc., also including the connection to some others optical coatings. When command Create (or Create branch), it is automatically allocated a memory area for 10 optical materials (non-initiated) and a memory area for 6 non-initiated structures for describing an optical coating (the Edit macro editing window contains 10 editing fields for optical materials and 6 fields for structure editing). The memory areas for optical materials and structures can be extended or reduced by different commands (such as: Edit / Edit coating / Coating materials and …..\ Edit structures), however the memory areas cannot be smaller than those necessary for 10 optical materials and 6 structures. Once this memory area was created, a new created coating will be displayed in the main window having the name "Root coating" or "Branch coating", depending on the command or the command context.
The following action in defining an optical coating is to initiate the used optical materials and to describe the optical coating by means of structures (Edit / Edit coating/ Edit macro). Once these are defined, command Generate. By command Generate, the memory areas are allocated for layer parameters and the group parameters, the memory areas connected to the memory area defining the coating (created by the command Create) and above-mentioned. The memory area for layer parameters is characteristic only for the root coatings (the memory area for groups is characteristic to all coatings). The branch coatings have not this memory area, they pointing, by groups, to the memory area for the layers parameters of the root coating.
Other commands that are to be subsequently analyzed, allocate some other memory areas where different parameters defining the optical coating are stored.
So as it was mentioned in the Generalities the data describing the optical coatings have an arborescent and dynamic structure. The first created optical coating is a root optical coating. The root optical coating defines a solution to a problem such as: number of layers, groups of layers, structures, optical materials. Starting from this root optical coating, branch coatings can be defined on the optical materials and layers of the root coating. The branch optical coatings can have other incident and emergent media, other incident angles, other polarization state of the incident radiation and they can be defined by a number of layers at most equal or smaller than that one of the root coating. It must be taken into account that if a layer is changed in the root coating, this change is viewed by all the branch coating including that layer. In fact, the branch coatings have not own layers but they are pointing to the layers of the root coatings. On the branch coatings, most analysis and optimization commands can be given.
So as it was above-mentioned, the data have an arborescent structure on different levels of arborescence. The menu command "Create" creates an optical coating at the level of an active coating when an command was given. For example, the first root coating was created, it also being the optical coating with focusing (it is active and the editing, analysis, optimization, etc. commands can be given on it). A new menu command "Create" will create a new root coating (so at the same level of arborescence), totally independent from the first root coating. The root optical coatings are totally independent, as between then, there is no connection concerning the structures of coatings (layers, materials, groups of layers, etc.). For example, it is possible to exist an antireflection root coating and a pass-band filter type root coating. If the active coating is a branch coating then the command "Create" will create a branch coating at the same level of arborescence with an active coating at the very moment of the command "Create".
Always, the new created coating becomes an active coating (on which, editing, analysis, etc. commands can be given).
The active optical coating has its name written on the black background inside the main window of the application.