OpenMaXwell Reference Manual

Home  General  Menues  Dialogs  Movie Directives  Formula Interpreter  File Structures

2D points    3D Objects    3D Points    Boundary    Cursor position    Data for selected object    Domain    Expansion    Field    Field components    Field formula    Field tubes    Function    Generate expansions along 2D boundary    Generate expansions for 3D objects    Grid formula    Grid transformation    Info and movie directives    Insert    Integral    Modify 2D expansions    MMP    Movie    Open GL window    PET basis    PFD (predefined FD)    Project     Space, plane, arrow, or point    Tools and draw    Transformation data    Window

Domain Dialog

Press the domain button   or select Domain... from the Tools menu to open this dialog.

Domain data

The Domain dialog displays the domain data and allows you to edit or modify this data. An OpenMaXwell domain is a bounded area filled with isotropic material, characterized by four formulae for the permittivity epsilon, the permeability mue, the electric conductivity sigma, and the magnetic conductivity tau. These formulae can be time or frequency dependent if you are working in the time or frequency domain respectively. During GFD and MMP computations, the formulae are evaluated and the resulting scalar values are used. In the time-harmonic case, these constants may be complex. Therefore, the formulae are assumed to be complex in general.

Note that sigma and tau are ignored in the MMP tools of OpenMaXwell because the complex definitions of  epsilon and mue already contain the conductivities in the imaginary parts. Instead of giving a real number, a complex number, or a formula, you may also provide a filename to specify the these values. The filename must be preceded by the character #. The corresponding file should be an ASCII file that contains the corresponding frequency- or wavelength dependence as a list. Whether the frequency- or the wavelength-dependence is specified depends on the file extension. The following extensions are recognized: file.FR1, file.FR2 (for frequency dependence), file.OM1, file.OM2 (for omega dependence, i.e., angular frequency values), file.WL1, file.WL2 (for wavelength dependence). Note that the third character of the extension may be either 1 or 2. 1 indicates that the material property is real and therefore specified in 1 column, whereas 2 specifies that material property is complex and therefore specified in 2 columns - the column 1 for the real part and column 2 for the imaginary part. Column 0 always contains the frequency, omega, or the wavelength - depending on the first two characters of the extension. Since it may be convenient to provide, for example, the wavelength in nm in column 0, the first line in the file that describes the material property is a scaling factor, e.g., 1.0e-9 when nm are used. Thus, a typical file for the complex permittivity may be named as epsilonAg.wl2 and it might start as follows:

 1.0e-9 ! wavelength scaling: nm
206.8390325 -0.34600 2.86200 ! wavelength in nm, real part of epsilon, imaginary part of epsilon
207.5303388 -0.34001 2.87797
208.2259319 -0.33402 2.89495
208.9265556 -0.32803 2.91192
209.6315556 -0.32304 2.92888
210.3416865 -0.31705 2.94585
211.0566449 -0.31106 2.96282

Note that you specify #epsilonAg.wl2 in the epsilon box when you wish that OpenMaXwell reads the data from this file. In order to obtain values between those specified in the list, OpenMaXwell uses linear interpolation. If a value outside the the range specified in the file is required, no interpolation is done. For example, when when you have specified the file given above and ask OpenMaXwell to compute the field for 100nm wavelength (which is <206.8390325, i.e., the first value specified in the file), the first value in the list will be used.

Whether sigma and tau values are used or not in analytic field definitions and in PFD (FDTD etc.) transformations, depends on the corresponding update scheme. In the current PFD-FDTD implementation, these values are used as follows: For standard materials with losses, epsilon, mue, sigma, and tau are real and positive. Note that these FD schemes are only stable for epsilon and mue >=1. When epsilon or mue <1, the material must be dispersive.

For dispersive materials, time domain solvers use various Drude-Lorentz models. For the MMP solver, arbitrary dispersive materials are described by a formula for epsilon or mue. The following formulas are available abbreviations for simple dispersive materials (Note that the last character defines the variable to be used: f stands fro frequency, o for omega, w for wavelength!):

See formula interpreter for details. The PFD-FDTD solver contains appropriate material models for these simple dispersive materials but not for arbitrary dispersive materials described by an arbitrary formula or even by an ASCII file.

Toggle domains

Only one domain’s data is displayed and available to be edited in the Domain dialog at a time. To select a domain, select the domains identifier in the Current box.

Modify domain data

To make changes in the edit boxes effective, press the Modify button or the Modify+Check button.

Check formula

When you press the Modify+Check button OpenMaXwell checks the formulae of all domains. It will put an exclamation mark in front of any formula that it detects an error.

Add a domain

Press the Add button to copy the current domain. OpenMaXwell will add a domain with the data specified in the epsilon, mue, and sigma boxes.

Delete a domain

Press the Delete button to delete the current domain. Note that there is no way to recover data once a domain has been deleted, except if you have saved the domain data explicitly. OpenMaXwell requires at least one domain to be present, and therefore prevents, you from deleting the current domain if only one domain is defined.

Read domain data

Press the Read… button to read domain data from a file. A file name dialog will allow you to select any file name to read the data from. Note that all current domains will be overwritten.

Write domain data

Press the Write… button to write domain data to a file. A file name dialog will allow you to select any file name to save the data to.

Draw the current domain

Sometimes it is desirable to see the boundaries of the current domain only in a graphics window. Clear the window and press the Draw current domain!! Button. Note that this will automatically close the dialog.

Close the dialog

Press the Close button to close the dialog. Note that any changes made to the domain data will be lost unless the Modify button was pressed to accept the changes.

 

Responsible for this web page:  Ch. Hafner, Computational Optics Group, IEF, ETH, 8092 Zurich, Switzerland

Last update 17.02.2014