# Fully Anisotropic Medium

FullyAnisotropicMedium defines a material with full permittivity and conductivity tensors.

This object corresponds to tidy3d.FullyAnisotropicMedium (opens new window).

The rotated diagonal option uses FullyAnisotropicMedium.from_diagonal (opens new window).

# Name

name: Optional unique name for the medium.

# Type

type: Medium model used by this material entry.

  • Options: Fully Anisotropic Medium

# Color

color: Display color used for the medium in the GUI.

  • Type: color
  • Default: automatically assigned by the GUI

# General Properties

type: Fully anisotropic material definition.

  • Options:
    • Full tensor: Directly define the full permittivity and conductivity tensors.
    • Rotated diagonally anisotropic medium: Define diagonal components and rotate them around an axis.

# Full Tensor

permittivity: Relative permittivity tensor.

  • Type: 3 by 3 matrix of float numbers
  • Unit: unitless
  • Default: [[1, 0, 0], [0, 1, 0], [0, 0, 1]]

conductivity: Electric conductivity tensor. The imaginary part of the complex permittivity tensor at angular frequency ω\omega is defined by σω\frac{\sigma}{\omega}.

  • Type: 3 by 3 matrix of float numbers
  • Unit: S/um
  • Default: [[0, 0, 0], [0, 0, 0], [0, 0, 0]]

# Rotated Diagonally Anisotropic Medium

Use this definition when the material is diagonal in its local coordinate system and rotated relative to the simulation axes. The GUI can define the diagonal material by Permittivity or by Refractive index.

# Permittivity

permittivity: Diagonal relative permittivity components used for the local XX, YY, and ZZ axes.

  • Type: three float numbers
  • Components: XX, YY, ZZ
  • Unit: unitless
  • Default: (1, 1, 1)

conductivity: Diagonal electric conductivity components used for the local XX, YY, and ZZ axes.

  • Type: three float numbers
  • Components: XX, YY, ZZ
  • Unit: S/um
  • Default: (0, 0, 0)

# Refractive Index

n: Real refractive index components used for the local XX, YY, and ZZ axes.

  • Type: three float numbers
  • Components: XX, YY, ZZ
  • Default: (0, 0, 0) in the GUI

k: Imaginary refractive index components used for the local XX, YY, and ZZ axes.

  • Type: three float numbers
  • Components: XX, YY, ZZ
  • Unit: S/um in the GUI
  • Default: (0, 0, 0)

wavelength_or_frequency: Choose whether the refractive index values are evaluated at a wavelength or a frequency.

  • Options: Wavelength/Frequency
  • Default: Frequency

freq: Frequency at which n and k are evaluated.

  • Type: float number
  • Unit: Hz, kHz, MHz, GHz, THz, or other available frequency unit

wavelength: Wavelength at which n and k are evaluated.

  • Type: float number
  • Unit: m, mm, um, nm, or other available length unit

# Rotation

axis: Axis of rotation.

  • Type: three float numbers
  • Components: X, Y, Z
  • Default: (0, 0, 0) in the GUI

angle: Rotation angle around axis.

  • Type: float number
  • Unit: degree
  • Default: 0

The diagonal definition constructs local xx, yy, and zz media and applies a rotation, corresponding to FullyAnisotropicMedium.from_diagonal.

# Advanced

set_from_global_frequency: Toggle whether the frequency range is set from the Global Settings frequency range.

  • Options:
    • True: Use the global frequency range and disable manual frequency range inputs.
    • False: Manually set frequency_range.

frequency_range: Optional range of validity for the medium.

  • Type: two float numbers
  • Unit: Hz, kHz, MHz, GHz, THz, or other available frequency unit
  • Default: None

allow_gain: Toggle whether the medium is allowed to be active.

  • Options: True/False
  • Default: False

NOTE

Fully anisotropic materials can increase simulation cost. Use Anisotropic Medium when diagonal anisotropy is sufficient.

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