# FluxMonitor

Monitor that records power flux through a plane in the frequency domain.

If the monitor geometry is a 2D box, the total flux through this plane is returned, with a positive sign corresponding to power flow in the positive direction along the axis normal to the plane.

If the geometry is a 3D box, the total power coming out of the box is returned by integrating the flux over all box surfaces (excpet the ones defined in exclude_surfaces).

Note: For a 2D plane, the flux is summed up over all Yee grid pixels that are touched by the plane, rather than integrated over the exact span of the plane. For a 3D monitor, this is also the case, but care is taken to not over- or under-count the power at the edges. Because of this, there can be small discrepancies between using a 3D FluxMonitor and manually placing six 2D monitors at the surface locations.

# Name

name: Unique name for monitor.

Required field

# Size and Position

Specification of the monitor size and position.

# Center + size

Object definition through a center position and size.

center: Center of the object in x, y, and z-directions.

Type: floating-point number

  • Unit: m, μm (default), or nm
  • Default: (0, 0, 0)

size: Size of the object in x, y, and z-directions.

Use Infinity to define a geometry extending to infinity in both directions along an axis.

Type: floating-point number

  • Unit: m, μm (default), or nm
  • Constraint: greater than or equal to 0
  • Required field

# Bounds

Object definition through minimum and maximum coordinate bounds.

min: Values of the x, y, and z coordinates defining the object lower corner.

Type: floating-point number

  • Unit: m, μm (default), or nm
  • Required field

max: Values of the x, y, and z coordinates defining the object upper corner.

Type: floating-point number

  • Unit: m, μm (default), or nm
  • Required field

# Frequencies

Definition of the monitor wavelengths/frequencies.

Options:

  • Wavelengths: Specify monitor wavelengths in units of m, μm (default), or nm.
  • Frequencies: Specify monitor frequencies in units of Hz (default) or THz.

Default: Wavelengths

# Enter wavelength/frequency range

Create an evenly spaced list of wavelength/frequency points between a minimum and a maximum value.

min: Minimum wavelength/frequency value.

  • Required field Default: None

max: Maximum wavelength/frequency value.

  • Required field Default: None

number of points: Number of wavelength/frequency points.

  • Required field Default: None

# Custom wavelength/frequency list

Create a custom list of wavelength/frequency points. Click the Edit list button to include, edit, or exclude wavelength/frequency values from the list.

# Downsampling

interval_space: Number of grid step intervals between monitor recordings.

  • If equal to 1, there will be no downsampling.
  • If greater than 1, fields will be downsampled and automatically colocated.

Type: integer

  • Unit: unitless
  • Constraint: greater than 0
  • Default: (1, 1, 1)

# Apodization

Sets parameters of (optional) apodization. Apodization applies a windowing function to the Fourier transform of the time-domain fields into frequency-domain ones, and can be used to truncate the beginning and/or end of the time signal, for example to eliminate the source pulse when studying the eigenmodes of a system.

Note: apodization affects the normalization of the frequency-domain fields.

start: Defines the time at which the start apodization ends.

Type: floating-point number

  • Unit: s (default), ps, or fs
  • Constraint: greater than or equal to 0

Default: None

end: Defines the time at which the end apodization begins.

Type: floating-point number

  • Unit: s (default), ps, or fs
  • Constraint: greater than or equal to 0

Default: None

width: Characteristic decay length of the apodization function.

Type: floating-point number

  • Unit: s (default), ps, or fs
  • Constraint: greater than or equal to 0

Default: None

# Normal Vector Orientation

normal_dir: Direction of the surface monitor’s normal vector w.r.t. the positive x, y or z unit vectors. Must be one of + or -. Applies to surface monitors only, and defaults to + if not provided.

Options:

  • +
  • -

Default: None, which means

  • None for volume monitors
  • + for surface monitors

# Excluded Surfaces

exclude_surfaces: Surfaces to exclude in the integration, if a volume monitor.

Options: select one or more of

  • x-
  • x+
  • y-
  • y+
  • z-
  • z+

Default: None

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