# Layers

Layers — MC Grating documentation for Modal Collinear and Modal Conical. The incidence always takes place from the cover medium and the layers are…

Canonical: https://mcgrating.com/docs/modal/layers.html


Written by Nikolay M. LyndinLast revised 2014-11-14

This documentation was written for releases up to 2018 and is being revised. Some dialogs have changed since. If something does not match what you see, write to [mc@mcgrating.com](mailto:mc@mcgrating.com).

- The incidence always takes place from the cover medium and the layers are enumerated from the cover to substrate medium. If the user wants to illuminate the structure from the substrate medium, the role of cover and substrate must be swapped. Button ***C-S*** swaps the role of cover and substrate and reverses the order of the layers inclusive of the grating.
- Each lamellar layer of ***Thickness*** with index ***Layer*** is divided into several Cells. The user can edit the Cells parameters individually.
- By clicking the right mouse button at ***Layer*** control the user activates the *Popup Menu* for editing the whole layer (copy, paste, etc.).
- By clicking the right mouse button at ***Cell Index*** control the user activates the *Popup Menu* for splitting or deleting the current Cell.
- By clicking the button ***Convert*** the user opens the ***[Layer Slicing](https://mcgrating.com/docs/modal/layer-slicing.html)*** dialog window.
- This page contains the **“*Material*”** control. If any of corresponding to the medium edit field is focused, by clicking this control the user can access to the Material Catalog though the [***Material*** ***Dialog***](https://mcgrating.com/docs/common/material.html) window. If a medium is assigned with a Material the **“*Material*”** control caption indicates the *Material name* and the software will always take a refractive index of this Material for a current value of wavelength otherwise the **“*Material*”** control caption is *“Select Material”* and medium refractive index will be fixed for all wavelengths.
- By clicking the right mouse button at the **“*Material*”** control the user activates the *Popup Menu* which helps to manipulate with the already set materials bypassing the [***Material*** ***Dialog***](https://mcgrating.com/docs/common/material.html) window.
- Other fields are obvious. It is necessary to emphasize the useful property of the *Permittivity* and *Refractive* index fields: after exiting from any field or after pressing the Enter key, all other fields in a line will be automatically recalculated.

**Note 1** The imagine part positive sign of the *Permittivity* and *Refractive* index corresponds to the dissipative media while the negative sign corresponds to the media with amplification.

**Note 2** Before any calculation of the structure or after pressing ***OK*** button the software automatically deletes cells of zero length and merges cells of plane layers and merges adjacent cells of identical permittivity in case the ***Merge Adjacent Cells ***box is checked ***[Options Dialog](https://mcgrating.com/docs/modal/options.html)***.

From the in-application help of Modal Collinear and Modal Conical, documented through 2018. If you publish results computed with MC Grating, see [how to cite it](https://mcgrating.com/references.html#cite).