tidy3d.SurfaceFieldTimeMonitor

tidy3d.SurfaceFieldTimeMonitor#

class SurfaceFieldTimeMonitor[source]#

Bases: AbstractSurfaceMonitor, TimeMonitor

Monitor that records electromagnetic fields in the time domain on PEC and lossy metal surfaces.

Parameters:

  • center (Optional[tuple[Union[float, autograd.tracer.Box], Union[float, autograd.tracer.Box], Union[float, autograd.tracer.Box]]] = None) – [units = um]. Center of object in x, y, and z.

  • size (tuple[Union[NonNegativeFloat, autograd.tracer.Box], Union[NonNegativeFloat, autograd.tracer.Box], Union[NonNegativeFloat, autograd.tracer.Box]]) – [units = um]. Size in x, y, and z directions.

  • name (str) – Unique name for monitor.

  • interval_space (tuple[Literal[1], Literal[1], Literal[1]] = (1, 1, 1)) – Number of grid step intervals between monitor recordings. Only the value of 1 (no downsampling) is currently supported for surface monitors.

  • colocate (Literal[True] = True) – For surface monitors fields are always colocated on surface.

  • use_colocated_integration (Literal[True] = True) – Whether to use colocated fields for flux, dot products, and overlap integrals. Hard-coded to True for most monitor types. Can be toggled on field and overlap monitors.

  • start (NonNegativeFloat = 0.0) – [units = sec]. Time at which to start monitor recording.

  • stop (Optional[NonNegativeFloat] = None) – [units = sec]. Time at which to stop monitor recording. If not specified, record until end of simulation.

  • interval (Optional[PositiveInt] = None) – Sampling rate of the monitor: number of time steps between each measurement. Set interval to 1 for the highest possible resolution in time. Higher integer values downsample the data by measuring every interval time steps. This can be useful for reducing data storage as needed by the application.

  • fields (tuple[Literal['E', 'H'], ...] = ['E', 'H']) – Collection of field components to store in the monitor.

Notes

SurfaceFieldTimeMonitor objects are best used to monitor the time dependence of the fields on PEC (PECMedium) and lossy metal (LossyMetalMedium) surfaces. They can also be used to create “animations” of the field pattern evolution.

To create an animation, we need to capture the frames at different time instances of the simulation. This can be done by using a SurfaceFieldTimeMonitor. Usually a FDTD simulation contains a large number of time steps and grid points. Recording the field at every time step and grid point will result in a large dataset. For the purpose of making animations, this is usually unnecessary.

Example

>>> import tidy3d as td
>>> old_logging_level = td.config.logging_level
>>> td.config.logging_level = "ERROR"
>>> monitor = SurfaceFieldTimeMonitor(
...     center=(1,2,3),
...     size=(2,2,2),
...     fields=['H'],
...     start=1e-13,
...     stop=5e-13,
...     interval=2,
...     name='movie_monitor')
>>> td.config.logging_level = old_logging_level

Attributes

fields

interval_space

colocate

start

stop

interval

use_colocated_integration

name

size

center

Methods

storage_size(num_cells, tmesh)

Size of monitor storage given the number of points after discretization.
storage_size(num_cells, tmesh)[source]#

Size of monitor storage given the number of points after discretization. In general, this is severely overestimated for surface monitors.