tidy3d.Structure#

class Structure[source]#

Bases: AbstractStructure

Defines a physical object that interacts with the electromagnetic fields. A Structure is a combination of a material property (AbstractMedium) and a Geometry.

Parameters:

attrs (dict = {}) – Dictionary storing arbitrary metadata for a Tidy3D object. This dictionary can be freely used by the user for storing data without affecting the operation of Tidy3D as it is not used internally. Note that, unlike regular Tidy3D fields, attrs are mutable. For example, the following is allowed for setting an attr obj.attrs['foo'] = bar. Also note that Tidy3D` will raise a TypeError if attrs contain objects that can not be serialized. One can check if attrs are serializable by calling obj.json().
geometry (Union[Box, Transformed, ClipOperation, GeometryGroup, Sphere, Cylinder, PolySlab, ComplexPolySlabBase, TriangleMesh]) – Defines geometric properties of the structure.
name (Optional[str] = None) – Optional name for the structure.
background_permittivity (Optional[ConstrainedFloatValue] = None) – DEPRECATED: Use Structure.background_medium. Relative permittivity used for the background of this structure when performing shape optimization with autograd.
background_medium (Union[Medium, AnisotropicMedium, PECMedium, PoleResidue, Sellmeier, Lorentz, Debye, Drude, FullyAnisotropicMedium, CustomMedium, CustomPoleResidue, CustomSellmeier, CustomLorentz, CustomDebye, CustomDrude, CustomAnisotropicMedium, PerturbationMedium, PerturbationPoleResidue, Medium2D, AnisotropicMediumFromMedium2D] = None) – Medium used for the background of this structure when performing shape optimization with autograd. This is required when the structure is embedded in another structure as autograd will use the permittivity of the Simulation by default to compute the shape derivatives.
medium (Union[Medium, AnisotropicMedium, PECMedium, PoleResidue, Sellmeier, Lorentz, Debye, Drude, FullyAnisotropicMedium, CustomMedium, CustomPoleResidue, CustomSellmeier, CustomLorentz, CustomDebye, CustomDrude, CustomAnisotropicMedium, PerturbationMedium, PerturbationPoleResidue, Medium2D, AnisotropicMediumFromMedium2D]) – Defines the electromagnetic properties of the structure’s medium.

Notes

Structures can indeed be larger than the simulation domain in tidy3d. In such cases, tidy3d will automatically truncate the geometry that goes beyond the domain boundaries. For best results, structures that intersect with absorbing boundaries or simulation edges should extend all the way through. In many such cases, an “infinite” size td.inf can be used to define the size along that dimension.

Example

>>> from tidy3d import Box, Medium
>>> box = Box(center=(0,0,1), size=(2, 2, 2))
>>> glass = Medium(permittivity=3.9)
>>> struct = Structure(geometry=box, medium=glass, name='glass_box')

See also

Notebooks:

Quickstart: Usage in a basic simulation flow.
First walkthrough: Usage in a basic simulation flow.
Visualizing geometries in Tidy3D

Lectures:

Using FDTD to Compute a Transmission Spectrum

GUI:

Structures

Attributes

attrs

Methods

`compute_derivatives`(derivative_info)	Compute adjoint gradients given the forward and adjoint fields
`eps_comp`(row, col, frequency, coords)	Single component of the complex-valued permittivity tensor as a function of frequency.
`eps_diagonal`(frequency, coords)	Main diagonal of the complex-valued permittivity tensor as a function of frequency.
`from_permittivity_array`(geometry, eps_data, ...)	Create `Structure` with `geometry` and `CustomMedium` containing `eps_data` for The `permittivity` field.
`get_monitor_name`(index, data_type)	Get the monitor name for either a field or permittivity monitor at given index.
`make_adjoint_monitors`(freqs, index)	Generate the field and permittivity monitor for this structure.
`to_gds`(cell[, x, y, z, ...])	Append a structure's planar slice to a .gds cell.
`to_gds_file`(fname[, x, y, z, ...])	Export a structure's planar slice to a .gds file.
`to_gdspy`([x, y, z, gds_layer, gds_dtype])	Convert a structure's planar slice to a .gds type polygon.
`to_gdstk`([x, y, z, permittivity_threshold, ...])	Convert a structure's planar slice to a .gds type polygon.

Inherited Common Usage

medium#

eps_diagonal(frequency, coords)[source]#

Main diagonal of the complex-valued permittivity tensor as a function of frequency.

Parameters:: frequency (float) – Frequency to evaluate permittivity at (Hz).
Returns:: The diagonal elements of the relative permittivity tensor evaluated at frequency.
Return type:: complex

static get_monitor_name(index, data_type)[source]#: Get the monitor name for either a field or permittivity monitor at given index.

make_adjoint_monitors(freqs, index)[source]#: Generate the field and permittivity monitor for this structure.

compute_derivatives(derivative_info)[source]#: Compute adjoint gradients given the forward and adjoint fields

eps_comp(row, col, frequency, coords)[source]#

Single component of the complex-valued permittivity tensor as a function of frequency.

Parameters:

row (int) – Component’s row in the permittivity tensor (0, 1, or 2 for x, y, or z respectively).
col (int) – Component’s column in the permittivity tensor (0, 1, or 2 for x, y, or z respectively).
frequency (float) – Frequency to evaluate permittivity at (Hz).

Returns:

Element of the relative permittivity tensor evaluated at frequency.

Return type:

complex

to_gdstk(x=None, y=None, z=None, permittivity_threshold=1, frequency=0, gds_layer=0, gds_dtype=0)[source]#

Convert a structure’s planar slice to a .gds type polygon.

Parameters:

x (float = None) – Position of plane in x direction, only one of x,y,z can be specified to define plane.
y (float = None) – Position of plane in y direction, only one of x,y,z can be specified to define plane.
z (float = None) – Position of plane in z direction, only one of x,y,z can be specified to define plane.
permittivity_threshold (float = 1.1) – Permitivitty value used to define the shape boundaries for structures with custom medim
frequency (float = 0) – Frequency for permittivity evaluaiton in case of custom medium (Hz).
gds_layer (int = 0) – Layer index to use for the shapes stored in the .gds file.
gds_dtype (int = 0) – Data-type index to use for the shapes stored in the .gds file.

Returns:

List of gdstk.Polygon

Return type:

List

to_gdspy(x=None, y=None, z=None, gds_layer=0, gds_dtype=0)[source]#

Convert a structure’s planar slice to a .gds type polygon.

Parameters:

x (float = None) – Position of plane in x direction, only one of x,y,z can be specified to define plane.
y (float = None) – Position of plane in y direction, only one of x,y,z can be specified to define plane.
z (float = None) – Position of plane in z direction, only one of x,y,z can be specified to define plane.
gds_layer (int = 0) – Layer index to use for the shapes stored in the .gds file.
gds_dtype (int = 0) – Data-type index to use for the shapes stored in the .gds file.

Returns:

List of gdspy.Polygon and gdspy.PolygonSet.

Return type:

List

to_gds(cell, x=None, y=None, z=None, permittivity_threshold=1, frequency=0, gds_layer=0, gds_dtype=0)[source]#

Append a structure’s planar slice to a .gds cell.

Parameters:

cell (gdstk.Cell or gdspy.Cell) – Cell object to which the generated polygons are added.
x (float = None) – Position of plane in x direction, only one of x,y,z can be specified to define plane.
y (float = None) – Position of plane in y direction, only one of x,y,z can be specified to define plane.
z (float = None) – Position of plane in z direction, only one of x,y,z can be specified to define plane.
permittivity_threshold (float = 1.1) – Permitivitty value used to define the shape boundaries for structures with custom medim
frequency (float = 0) – Frequency for permittivity evaluaiton in case of custom medium (Hz).
gds_layer (int = 0) – Layer index to use for the shapes stored in the .gds file.
gds_dtype (int = 0) – Data-type index to use for the shapes stored in the .gds file.

to_gds_file(fname, x=None, y=None, z=None, permittivity_threshold=1, frequency=0, gds_layer=0, gds_dtype=0, gds_cell_name='MAIN')[source]#

Export a structure’s planar slice to a .gds file.

Parameters:

fname (str) – Full path to the .gds file to save the Structure slice to.
x (float = None) – Position of plane in x direction, only one of x,y,z can be specified to define plane.
y (float = None) – Position of plane in y direction, only one of x,y,z can be specified to define plane.
z (float = None) – Position of plane in z direction, only one of x,y,z can be specified to define plane.
permittivity_threshold (float = 1.1) – Permitivitty value used to define the shape boundaries for structures with custom medim
frequency (float = 0) – Frequency for permittivity evaluaiton in case of custom medium (Hz).
gds_layer (int = 0) – Layer index to use for the shapes stored in the .gds file.
gds_dtype (int = 0) – Data-type index to use for the shapes stored in the .gds file.
gds_cell_name (str = 'MAIN') – Name of the cell created in the .gds file to store the geometry.

classmethod from_permittivity_array(geometry, eps_data, **kwargs)[source]#: Create Structure with geometry and CustomMedium containing eps_data for The permittivity field. Extra keyword arguments are passed to td.Structure().

__hash__()#: Hash method.

tidy3d.Structure

Contents

tidy3d.Structure#