Time Monitor Setting

This section describes Time monitor.

Use Time monitor to record electromagnetic field in time domain in a specified geometric space.

Select Time monitor from the solver tab, create a Time monitor in the Composite viewer, and set relevant parameters in a properties editing interface that automatically pops up.

Time Monitor Setting

General Setting

The General tab is about general settings for the Time monitor.

Data Monitoring

Name	Description
Data type	Record data type, which is Time-domain by default; this is a read-only parameter.
Spatial interpolation	Select types of spatial interpolation by drop-down: None: no spatial interpolation is performed; record electromagnetic field components at different locations within the Yee cell; Mesh cell: record each component of the electric and magnetic fields at different locations on the Yee cell. To accurately calculate the Poynting vector, you can choose to interpolate electromagnetic field components to the same location on the Yee cell. After selecting this option for spatial interpolation, field values are interpolated to the nearest Yee cell boundary.
Record data in PML	Record data in the PML region, which is an advanced setting and not checked by default.

Components

Name	Description
Components	Field components: Ex, Ey, Ez; Hx, Hy, Hz; Poynting vector: Px, Py, Pz.

The difference between Time monitor and the FDFP monitor is as follows:

• Time monitor records time-domain field, such as $Ex(t)$;
• FDFP monitor obtains frequency-domain field, such as $Ex(\omega)$.

Time Region

Name	Description
Stop time type	Set ways to stop simulation. Set stop time: User-defined time for stopping simulation; End of simulation: The moment the simulation actually ends is used as the stop time.
Start time	Time when recording begins.
Stop time	Time when recording stops. This option is enabled when choosing Set stop time for Stop time type.

Time Sampling

Name	Description
Min sampling per cycle	Minimum amount of sampling per cycle; used to set number of sampling points per cycle. Default value is 10.
Sampling rate	Representing amount of sampling per unit time for a continuous signal.
Sample time(per # of dt)	Time interval of sampling during simulation, that is, after how many time steps a sample is taken from the field.

Space Sampling

Name	Description
Per # of dx/dy/dz	Interval at which sampling is performed in the X/Y/Z direction during the simulation process, that is, after how many discretization steps a sampling is conducted.

Geometric Dimensions

Geometry is the geometric setting tab for Time monitor. Please refer to geometric dimensions setting of the monitor.

Data Visualizer

Use Time monitor to save time-domain information of the simulation process.

After completing simulation, you can view the returned result in the Data visualizer of Time monitor. Types of result data include:

• E: Data of electric field changing over time;
• H: Data of magnetic field changing over time.

In the Data visualizer of the Time monitor, you can view field distribution in time-domain by the following operations:

Case: Bragg Microcavity

In this case, FDTD is used to analyze the resonance spectrum of a one-dimensional Bragg grating resonator based on optical waveguide, and to calculate resonance frequency and quality factor Q. Signal data can be viewed from the Time monitor. For specific details, please refer to Bragg Microcavity.