fouriax.ThinLens

class ThinLens(focal_length_um, aperture_diameter_um=None)

Bases: OpticalLayer

Ideal thin lens applying a hyperbolic optical-path phase delay.

Parameters:

• focal_length_um (float)

• aperture_diameter_um (float | None)

__init__(focal_length_um, aperture_diameter_um=None)

Parameters:

• focal_length_um (float)

• aperture_diameter_um (float | None)

Return type:

None

Methods

__init__(focal_length_um[, aperture_diameter_um])
forward(field)	Apply this layer's optical transformation to field.
parameters()	Return trainable or configurable layer parameters.
validate_for(field)	Check that field is compatible with this layer.

Attributes

aperture_diameter_um
focal_length_um

focal_length_um: float

aperture_diameter_um: float | None = None

forward(field)

Apply this layer’s optical transformation to field.

Parameters:

field (Field) – Input optical field to transform.

Returns:

Transformed field. Subclasses should preserve batch axes, wavelength axes, and metadata unless the layer explicitly changes them.

Return type:

Field

parameters()

Return trainable or configurable layer parameters.

Returns an empty dict by default. Subclasses override this to expose arrays that should be updated during optimisation.

Return type:

dict[str, Array]