ExtrusionSpec¶

class photonforge.ExtrusionSpec(mask_spec, medium, limits, sidewall_angle=0)¶

Extrusion specification for masks.

This class is mainly used to create extrusion recipes for a Technology.

Parameters:

mask_spec – Mask specification for this extrusion.
medium – Tidy3D medium for the resulting structures. Different media can be used for optical and electrical frequencies by using a dictionary (see note below).
limits – Out-of-plane extrusion limits.
sidewall_angle – Sidewall angle for extrusion (in degrees). Affects the bottom face of the extruded mask (reference on top). Positive (negative) values will dilate (erode) the bottom face.

Example

>>> extrusion_spec = ExtrusionSpec(
...     MaskSpec((1, 0)),
...     td.Medium(permittivity=3.48**2),
...     limits=(0, 0.250),
...     sidewall_angle=8,
... )

Note

The medium used for simulations in optical and electrical frequency ranges (see frequency_classification()) can be set individually with:

>>> media = {
...     "optical": td.Medium(permittivity=3.48**2),
...     "electrical": td.Medium(permittivity=12.3),
... }
>>> extrusion_spec = ExtrusionSpec(
...     MaskSpec((1, 0)),
...     medium=media,
...     limits=(0, 0.250),
...     sidewall_angle=8,
... )

Methods

`copy`([deep])	Create a copy of this extrusion specification.
`extrude`(*structures[, extrusion_tolerance, ...])	Extrude planar structures according to this extrusion specification.
`from_json`(json_str)	Create an extrusion specification object from a json string.
`get_medium`(classification)	Return electrical or optical medium for this extrusion specification.

Attributes

`json`	Json representation of this extrusion specification.
`limits`	Extrusion limits.
`mask_spec`	Extrusion mask specification.
`medium`	Extrusion medium.
`sidewall_angle`	Extrusion sidewall_angle.

copy(deep=False)¶

Create a copy of this extrusion specification.

Parameters:: deep – If set, creates a copy of mask specification as well. Otherwise, the same mask specification object will be used.
Returns:: New copy.

extrude(*structures, extrusion_tolerance=0, classification='optical')¶

Extrude planar structures according to this extrusion specification.

Parameters:

*structures – Structures to be extruded. Must be instances of Rectangle, Circle, :class:`Polygon, or Path.
extrusion_tolerance – Minimal dimension to search for topological changes in angled extrusions or fallback to an orthogonal profile. A value of 0 or less defaults to config.tolerance.
classsification – Frequency classification indicating which type of medium to use. One of "electrical" or "optical".

Returns:

List of polyhedra.

Note

The mask specification in this object is not taken into account. All structures are used in the extrusion and no dilation is applied.

static from_json(json_str)¶

Create an extrusion specification object from a json string.

Parameters:: json_str – Strig containing the json data.
Returns:: ExtrusionSpec instance.

get_medium(classification)¶

Return electrical or optical medium for this extrusion specification.

Parameters:: classification – One of "electrical" or "optical".
Returns:: Medium.