# GaussianOverlapMonitor

Monitor that records the overlap integral between simulated fields and a Gaussian beam profile. This provides a direct measurement of how efficiently a simulated field couples into a Gaussian beam, which is useful for fiber coupling efficiency calculations and free-space beam quality analysis.

# 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

# Direction

direction: Specifies propagation in the positive or negative direction of the injection axis.

Options:

+: Propagate in the positive direction of the injection axis
-: Propagate in the negative direction of the injection axis

Required field

# Waist Radius

waist_radius: Radius of the Gaussian beam at the waist.

Type: floating-point number

Unit: m, μm (default), or nm
Constraint: greater than 0
Default: 1

# Waist Distance

waist_distance: Distance from the beam waist along the propagation direction. When direction is + and waist_distance is positive, the waist is behind the monitor plane. When direction is + and waist_distance is negative, the waist is in front of the monitor plane.

Type: floating-point number

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

# Polar Angle

angle_theta: Polar angle of the propagation axis from the injection axis.

Type: floating-point number

Unit: rad or degree (default)
Default: 0

# Azimuth Angle

angle_phi: Azimuth angle of the propagation axis in the plane orthogonal to the injection axis.

Type: floating-point number

Unit: rad or degree (default)
Default: 0

# Polarization Angle

pol_angle: Specifies the angle between the electric field polarization and the plane defined by the injection axis and the propagation axis.

0 specifies P polarization (default)
90 degrees or π/2 rad specifies S polarization

Type: floating-point number

Unit: rad or degree (default)
Default: 0

# 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)

# Colocate Fields

colocate: Toggle whether fields should be colocated to grid cell boundaries (i.e. primal grid nodes).

Options:

False: Fields will NOT be colocated to grid cell boundaries.
True: Fields will be colocated to grid cell boundaries.

Default: True

# Conjugated Dot Product

conjugated_dot_product: Use conjugated or non-conjugated dot product for the overlap integral computation.

Options:

False: Use non-conjugate dot product.
True: Use conjugate dot product.

Default: True

# Number of Frequency Points

num_freqs: Number of points used to approximate the frequency dependence of the Gaussian beam profile.

Type: integer

Default: 3

# 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

# Store Fields

store_fields_direction: When Store Fields = True, the Gaussian beam field datasets are available in the simulation results. The beam propagation direction is selected using the Direction toggle.

Options:

None (default): It means that Store Fields is unchecked and the field datasets will NOT be available in simulation results.
+: It means that Store Fields is checked and the field datasets will be available in simulation results for the + (Forward) propagation direction.
-: It means that Store Fields is checked and the field datasets will be available in simulation results for the - (Backward) propagation direction.

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