These monitors provide time-domain information about electric and magnetic field components over the course of the simulation. Time-domain monitors can consist of point, surface, or volume monitors to capture this information over different spatial extents within the DGTD simulation region.
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Tip: Computations requirements Memory: Time domain field monitors can require large amounts of memory when recording data over a large spatial domain. When possible, use 1D rather than 2D or 3D monitors. Similarly, you can reduce the duration of time where data is recorded. Finally, changing the value of minimum sampling per cycle can be also used to minimize the amount of data collected. Computation time: Generally, time monitors don't have a large effect on the simulation time. |
General tab
The general tab for the time domain monitor includes options to edit the amount of data, and time period over which data is collected.
- STOP METHOD: End of simulation; Choose stop time
- START TIME: The time to start recording
- STOP TIME: The time to stop recording
- MIN SAMPLING PER CYCLE: This parameter determines the minimum amount of sampling per optical cycle that can be used. By default, it is set at 10.
Geometry tab
Geometry type
- SURFACE
- VOLUME
- POINT
| Note: A list of domains will be available under the SIMULATION REGION object once the simulation region is partitioned. A list of solids (primitives) are available under the GEOMETRY Container Group. |
Volume, surface, line and point in 3D and 2D:
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Volume |
Surface |
Point |
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3D |
Volume |
Surface or Line |
Point |
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2D |
Surface |
Line |
Point |
Surface Type
- DOMAIN:EXTERIOR : Select the target domain. The reference geometry is the common surface(s) shared by the uttermost surface(s) of the selected domain and the simulation region. The selected domain has to have at least a surface that is shared with one of the simulation region surfaces.
- DOMAIN:DOMAIN : Select the target domains. The reference geometry is the common surface(s) shared by the two selected domains.
- DOMAIN : Select the target domain. The reference geometry is the surfaces of the selected domain.
- SOLID : Select the target solid. The reference geometry is the surfaces that enclose the selected volume if the solid is a 3D shape, or the surface if the solid is a 2D plane.
- SIMULATION REGION : Select one or more simulation region boundaries. The reference geometry is the selected boundaries.
- SOLID:SIMULATION REGION : Select one or more simulation region boundaries and the target solid. The reference geometry is the common surface(s) shared by the simulation region and the target solid.
- MATERIAL:MATERIAL : Select the target materials. The reference geometry is the surface(s) that is shared by the two selected materials. This is only available in some boundary conditions.
- SURFACE : Type the identifier of the partition surface. If the target partition surface is SURFACE 3, type 3. If the target partition surfaces are SURFACE 3 and SURFACE 5, enter 3,5.
Volume Type
- SOLID : Select the target solid. The reference geometry is the volume of the selected solid.
- DOMAIN : Select the target domain. This is a volume enclosed by the target domain(s). If the target domain is DOMAIN 3, type 3. If the target domain are DOMAIN 3 and DOMAIN 5, enter 3,5.
- ALL DOMAINS : The target volume is the whole simulation region
Point
- X,Y,Z : The position of the point.
Results returned
Resulting dataset "FIELDS" provides:
- E: Electric field data as a function of position and time. Separate electric field components Ex, Ey and Ez are available.
- H: Magnetic field data as a function of position and time. Separate electric field components Hx, Hy and Hz are available
- TIME: Time points at which the E fields are sampled through the simulation
The following code can be used in conjunction with the attached simulation and script files to calculate the spectrum from time domain data saved in point field time monitor named "monitor".
# this code can be used to manually calculate the
# spectrum result from time monitor data
# get E/H time domain fields
fields = getresult("DGTD::monitor","fields");
E = fields.E; H = fields.H;
# user can specify frequency range of interest
f = linspace(50e12,1000e12,10000);
# calculate czt of time domain data
Exw = czt(pinch(fields.Ex),fields.time,2*pi*f);
Eyw = czt(pinch(fields.Ey),fields.time,2*pi*f);
Ezw = czt(pinch(fields.Ez),fields.time,2*pi*f);
Hxw = czt(pinch(fields.Hx),fields.time,2*pi*f);
Hyw = czt(pinch(fields.Hy),fields.time,2*pi*f);
Hzw = czt(pinch(fields.Hz),fields.time,2*pi*f);
# package results into a dataset select("DGTD::monitor");
spectrum = rectilineardataset("spectrum",get("x"),get("y"),get("z"));
spectrum.addparameter("lambda",c/f,"f",f);
spectrum.addattribute("E",Exw,Eyw,Ezw);
spectrum.addattribute("H",Hxw,Hyw,Hzw);
# visualize dataset
visualize(spectrum);