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Propagators

MFT

Bases: Propagator

Propagates a Wavefront using the MFT algorithm, allowing for the pixel_scale and number of pixels to be specified in the output plane.

UML

UML

Attributes:

Name Type Description
npixels int

The number of pixels in the output plane.
pixel_scale (float, meters / pixel or radians / pixel)

The pixel scale in the output plane. Has units of radians/pixel if focal_length is None, else meters/pixel.
focal_length (float, meters)

The focal_length of the lens/mirror this propagator represents. If None, the output pixel_scale has units radians/pixel, else meters/pixels.
Source code in src/dLux/layers/propagators.py 
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class MFT(Propagator):
    """
    Propagates a `Wavefront` using the MFT algorithm, allowing for the pixel_scale and
    number of pixels to be specified in the output plane.

    ??? abstract "UML"
        ![UML](../../assets/uml/MFT.png)

    Attributes
    ----------
    npixels : int
        The number of pixels in the output plane.
    pixel_scale : float, meters/pixel or radians/pixel
        The pixel scale in the output plane. Has units of radians/pixel if focal_length
        is None, else meters/pixel.
    focal_length : float, meters
        The focal_length of the lens/mirror this propagator represents. If None, the
        output pixel_scale has units radians/pixel, else meters/pixels.
    """

    npixels: int
    pixel_scale: float

    def __init__(
        self: Propagator,
        npixels: int,
        pixel_scale: float,
        focal_length: float = None,
    ):
        """
        Parameters
        ----------
        npixels : int
            The number of pixels in the output plane.
        pixel_scale : float, meters/pixel or radians/pixel
            The pixel scale in the output plane. Has units of radians/pixel if
            focal_length is None, else meters/pixel.
        focal_length : float = None, meters
            The focal_length of the lens/mirror this propagator represents. If None,
            the output pixel_scale has units radians/pixel, else meters/pixels.
        """
        super().__init__(focal_length=focal_length)

        self.pixel_scale = float(pixel_scale)
        self.npixels = int(npixels)

    def apply(self: Propagator, wavefront: Wavefront) -> Wavefront:
        """
        Applies the layer to the wavefront.

        Parameters
        ----------
        wavefront : Wavefront
            The wavefront to operate on.

        Returns
        -------
        wavefront : Wavefront
            The transformed wavefront.
        """
        return wavefront.propagate(
            self.npixels,
            self.pixel_scale,
            self.focal_length,
        )

__init__(npixels, pixel_scale, focal_length=None)

Parameters:

Name Type Description Default
npixels int

The number of pixels in the output plane.

 required
pixel_scale (float, meters / pixel or radians / pixel)

The pixel scale in the output plane. Has units of radians/pixel if focal_length is None, else meters/pixel.

 required
focal_length float = None, meters

The focal_length of the lens/mirror this propagator represents. If None, the output pixel_scale has units radians/pixel, else meters/pixels.

 None
Source code in src/dLux/layers/propagators.py 
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def __init__(
    self: Propagator,
    npixels: int,
    pixel_scale: float,
    focal_length: float = None,
):
    """
    Parameters
    ----------
    npixels : int
        The number of pixels in the output plane.
    pixel_scale : float, meters/pixel or radians/pixel
        The pixel scale in the output plane. Has units of radians/pixel if
        focal_length is None, else meters/pixel.
    focal_length : float = None, meters
        The focal_length of the lens/mirror this propagator represents. If None,
        the output pixel_scale has units radians/pixel, else meters/pixels.
    """
    super().__init__(focal_length=focal_length)

    self.pixel_scale = float(pixel_scale)
    self.npixels = int(npixels)

apply(wavefront)

Applies the layer to the wavefront.

Parameters:

Name Type Description Default
wavefront Wavefront

The wavefront to operate on.

 required

Returns:

Name Type Description
wavefront Wavefront

The transformed wavefront.
Source code in src/dLux/layers/propagators.py 
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def apply(self: Propagator, wavefront: Wavefront) -> Wavefront:
    """
    Applies the layer to the wavefront.

    Parameters
    ----------
    wavefront : Wavefront
        The wavefront to operate on.

    Returns
    -------
    wavefront : Wavefront
        The transformed wavefront.
    """
    return wavefront.propagate(
        self.npixels,
        self.pixel_scale,
        self.focal_length,
    )

FFT

Bases: Propagator

Propagates a Wavefront using the FFT algorithm.

UML

UML

TODO: Update padding to take in units of npixels, rather than factor.

Attributes:

Name Type Description
focal_length float

The focal_length of the lens/mirror this propagator represents. If None, the output pixel_scale has units radians/pixel, else meters/pixels.
pad int

The zero-padding factor to apply to the Wavefront before propagation. In general, this should be greater than 2 to avoid aliasing.
Source code in src/dLux/layers/propagators.py 
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class FFT(Propagator):
    """
    Propagates a `Wavefront` using the FFT algorithm.

    ??? abstract "UML"
        ![UML](../../assets/uml/FFT.png)

    # TODO: Update padding to take in units of npixels, rather than factor.

    Attributes
    ----------
    focal_length : float
        The focal_length of the lens/mirror this propagator represents. If None, the
        output pixel_scale has units radians/pixel, else meters/pixels.
    pad : int
        The zero-padding factor to apply to the `Wavefront` before propagation. In
        general, this should be greater than 2 to avoid aliasing.
    """

    pad: int

    def __init__(self: Propagator, focal_length: float = None, pad: int = 2):
        """
        Parameters
        ----------
        focal_length : float = None
            The focal_length of the lens/mirror this propagator represents. If None, the
            output pixel_scale has units radians/pixel, else meters/pixels.
        pad : int = 2
            The zero-padding factor to apply to the `Wavefront` before propagation. In
            general, this should be greater than 2 to avoid aliasing.
        """
        super().__init__(focal_length=focal_length)
        self.pad = int(pad)

    def apply(self: Propagator, wavefront: Wavefront) -> Wavefront:
        """
        Applies the layer to the wavefront.

        Parameters
        ----------
        wavefront : Wavefront
            The wavefront to operate on.

        Returns
        -------
        wavefront : Wavefront
            The transformed wavefront.
        """
        return wavefront.propagate_FFT(self.focal_length, self.pad)

__init__(focal_length=None, pad=2)

Parameters:

Name Type Description Default
focal_length float = None

The focal_length of the lens/mirror this propagator represents. If None, the output pixel_scale has units radians/pixel, else meters/pixels.

 None
pad int = 2

The zero-padding factor to apply to the Wavefront before propagation. In general, this should be greater than 2 to avoid aliasing.

 2
Source code in src/dLux/layers/propagators.py 
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def __init__(self: Propagator, focal_length: float = None, pad: int = 2):
    """
    Parameters
    ----------
    focal_length : float = None
        The focal_length of the lens/mirror this propagator represents. If None, the
        output pixel_scale has units radians/pixel, else meters/pixels.
    pad : int = 2
        The zero-padding factor to apply to the `Wavefront` before propagation. In
        general, this should be greater than 2 to avoid aliasing.
    """
    super().__init__(focal_length=focal_length)
    self.pad = int(pad)

apply(wavefront)

Applies the layer to the wavefront.

Parameters:

Name Type Description Default
wavefront Wavefront

The wavefront to operate on.

 required

Returns:

Name Type Description
wavefront Wavefront

The transformed wavefront.
Source code in src/dLux/layers/propagators.py 
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def apply(self: Propagator, wavefront: Wavefront) -> Wavefront:
    """
    Applies the layer to the wavefront.

    Parameters
    ----------
    wavefront : Wavefront
        The wavefront to operate on.

    Returns
    -------
    wavefront : Wavefront
        The transformed wavefront.
    """
    return wavefront.propagate_FFT(self.focal_length, self.pad)

TODO: Update padding to take in units of npixels, rather than factor.

ShiftedMFT

Bases: MFT

Propagates a Wavefront using the MFT algorithm, allowing for the pixel_scale and number of pixels to be specified in the output plane. Also optionally allows for a shift to be applied to the wavefront in the output plane.

UML

UML

Attributes:

Name Type Description
npixels int

The number of pixels in the output plane.
pixel_scale (float, meters / pixel or radians / pixel)

The pixel scale in the output plane. Has units of radians/pixel if focal_length is None, else meters/pixel.
focal_length (float, meters)

The focal_length of the lens/mirror this propagator represents. If None, the output pixel_scale has units radians/pixel, else meters/pixels.
shift Array

The (x, y) shift to apply to the wavefront in the output plane.
pixel bool

If True the shift value is assumed to be in units of pixels, else the physical units of the output plane (ie radians if focal_length is None, else meters).
Source code in src/dLux/layers/propagators.py 
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class ShiftedMFT(MFT):
    """
    Propagates a `Wavefront` using the MFT algorithm, allowing for the pixel_scale and
    number of pixels to be specified in the output plane. Also optionally allows for a
    shift to be applied to the wavefront in the output plane.

    ??? abstract "UML"
        ![UML](../../assets/uml/ShiftedMFT.png)

    Attributes
    ----------
    npixels : int
        The number of pixels in the output plane.
    pixel_scale : float, meters/pixel or radians/pixel
        The pixel scale in the output plane. Has units of radians/pixel if focal_length
        is None, else meters/pixel.
    focal_length : float, meters
        The focal_length of the lens/mirror this propagator represents. If None, the
        output pixel_scale has units radians/pixel, else meters/pixels.
    shift : Array
        The (x, y) shift to apply to the wavefront in the output plane.
    pixel : bool
        If True the shift value is assumed to be in units of pixels, else the physical
        units of the output plane (ie radians if focal_length is None, else meters).
    """

    shift: Array
    pixel: bool

    def __init__(
        self: Propagator,
        npixels: int,
        pixel_scale: float,
        shift: Array,
        focal_length: float = None,
        pixel: bool = False,
    ):
        """
        Parameters
        ----------
        npixels : int
            The number of pixels in the output plane.
        pixel_scale : float, meters/pixel or radians/pixel
            The pixel scale in the output plane. Has units of radians/pixel if
            focal_length is None, else meters/pixel.
        shift : Array
            The (x, y) shift to apply to the wavefront in the output plane.
        focal_length : float = None, meters
            The focal_length of the lens/mirror this propagator represents. If None,
            the output pixel_scale has units radians/pixel, else meters/pixels.
        pixel : bool = False
            If True the shift value is assumed to be in units of pixels, else the
            physical units of the output plane (ie radians if focal_length is None,
            else meters).
        """
        super().__init__(
            pixel_scale=pixel_scale,
            npixels=npixels,
            focal_length=focal_length,
        )

        self.shift = np.asarray(shift, float)
        self.pixel = bool(pixel)

        if self.shift.shape != (2,):
            raise ValueError(
                f"Shift must be a 2D array, got {self.shift.shape}."
            )

    def apply(self: Propagator, wavefront: Wavefront) -> Wavefront:
        """
        Applies the layer to the wavefront.

        Parameters
        ----------
        wavefront : Wavefront
            The wavefront to operate on.

        Returns
        -------
        wavefront : Wavefront
            The transformed wavefront.
        """
        return wavefront.propagate(
            self.npixels,
            self.pixel_scale,
            self.focal_length,
            self.shift,
            self.pixel,
        )

__init__(npixels, pixel_scale, shift, focal_length=None, pixel=False)

Parameters:

Name Type Description Default
npixels int

The number of pixels in the output plane.

 required
pixel_scale (float, meters / pixel or radians / pixel)

The pixel scale in the output plane. Has units of radians/pixel if focal_length is None, else meters/pixel.

 required
shift Array

The (x, y) shift to apply to the wavefront in the output plane.

 required
focal_length float = None, meters

The focal_length of the lens/mirror this propagator represents. If None, the output pixel_scale has units radians/pixel, else meters/pixels.

 None
pixel bool = False

If True the shift value is assumed to be in units of pixels, else the physical units of the output plane (ie radians if focal_length is None, else meters).

 False
Source code in src/dLux/layers/propagators.py 
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def __init__(
    self: Propagator,
    npixels: int,
    pixel_scale: float,
    shift: Array,
    focal_length: float = None,
    pixel: bool = False,
):
    """
    Parameters
    ----------
    npixels : int
        The number of pixels in the output plane.
    pixel_scale : float, meters/pixel or radians/pixel
        The pixel scale in the output plane. Has units of radians/pixel if
        focal_length is None, else meters/pixel.
    shift : Array
        The (x, y) shift to apply to the wavefront in the output plane.
    focal_length : float = None, meters
        The focal_length of the lens/mirror this propagator represents. If None,
        the output pixel_scale has units radians/pixel, else meters/pixels.
    pixel : bool = False
        If True the shift value is assumed to be in units of pixels, else the
        physical units of the output plane (ie radians if focal_length is None,
        else meters).
    """
    super().__init__(
        pixel_scale=pixel_scale,
        npixels=npixels,
        focal_length=focal_length,
    )

    self.shift = np.asarray(shift, float)
    self.pixel = bool(pixel)

    if self.shift.shape != (2,):
        raise ValueError(
            f"Shift must be a 2D array, got {self.shift.shape}."
        )

apply(wavefront)

Applies the layer to the wavefront.

Parameters:

Name Type Description Default
wavefront Wavefront

The wavefront to operate on.

 required

Returns:

Name Type Description
wavefront Wavefront

The transformed wavefront.
Source code in src/dLux/layers/propagators.py 
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def apply(self: Propagator, wavefront: Wavefront) -> Wavefront:
    """
    Applies the layer to the wavefront.

    Parameters
    ----------
    wavefront : Wavefront
        The wavefront to operate on.

    Returns
    -------
    wavefront : Wavefront
        The transformed wavefront.
    """
    return wavefront.propagate(
        self.npixels,
        self.pixel_scale,
        self.focal_length,
        self.shift,
        self.pixel,
    )

FarFieldFresnel

Bases: ShiftedMFT

Propagates a Wavefront using the MFT algorithm, modified to allows for more accurate representations of wavefront behaviour in the far-field regime, a few wavelengths away from focus in either direction. Allows for the pixel_scale and number of pixels to be specified in the output plane, and optionally allows for a shift to be applied to the wavefront in the output plane.

UML

UML

Attributes:

Name Type Description
npixels int

The number of pixels in the output plane.
pixel_scale float, meters/

The pixel scale in the output plane.
focal_length (float, meters)

The focal_length of the lens/mirror this propagator represents.
shift Array

The (x, y) shift to apply to the wavefront in the output plane.
pixel bool

If True the shift value is assumed to be in units of pixels, else the physical units of the output plane.
focal_shift (float, meters)

The shift in the propagation distance of the wavefront from focus.
Source code in src/dLux/layers/propagators.py 
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class FarFieldFresnel(ShiftedMFT):
    """
    Propagates a `Wavefront` using the MFT algorithm, modified to allows for more
    accurate representations of wavefront behaviour in the far-field regime, a few
    wavelengths away from focus in either direction. Allows for the pixel_scale and
    number of pixels to be specified in the output plane, and optionally allows for a
    shift to be applied to the wavefront in the output plane.

    ??? abstract "UML"
        ![UML](../../assets/uml/FarFieldFresnel.png)

    Attributes
    ----------
    npixels : int
        The number of pixels in the output plane.
    pixel_scale : float, meters/
        The pixel scale in the output plane.
    focal_length : float, meters
        The focal_length of the lens/mirror this propagator represents.
    shift : Array
        The (x, y) shift to apply to the wavefront in the output plane.
    pixel : bool
        If True the shift value is assumed to be in units of pixels, else the physical
        units of the output plane.
    focal_shift : float, meters
        The shift in the propagation distance of the wavefront from focus.
    """

    focal_shift: float

    def __init__(
        self: Propagator,
        npixels: int,
        pixel_scale: float,
        focal_length: float,
        focal_shift: float,
        shift: Array = np.zeros(2),
        pixel: bool = False,
    ):
        """
        Parameters
        ----------
        npixels : int
            The number of pixels in the output plane.
        pixel_scale : float, meters/
            The pixel scale in the output plane.
        focal_length : float, meters
            The focal_length of the lens/mirror this propagator represents.
        focal_shift : float, meters
            The shift in the propagation distance of the wavefront from focus.
        shift : Array = np.zeros(2)
            The (x, y) shift to apply to the wavefront in the output plane.
        pixel : bool = False
            If True the shift value is assumed to be in units of pixels, else the
            physical units of the output plane.
        """
        self.focal_shift = float(focal_shift)
        super().__init__(
            shift=shift,
            pixel=pixel,
            focal_length=focal_length,
            pixel_scale=pixel_scale,
            npixels=npixels,
        )

    def apply(self: Propagator, wavefront: Wavefront) -> Wavefront:
        """
        Applies the layer to the wavefront.

        Parameters
        ----------
        wavefront : Wavefront
            The wavefront to operate on.

        Returns
        -------
        wavefront : Wavefront
            The transformed wavefront.
        """
        return wavefront.propagate_fresnel(
            self.npixels,
            self.pixel_scale,
            self.focal_length,
            self.focal_shift,
            self.shift,
            self.pixel,
        )

__init__(npixels, pixel_scale, focal_length, focal_shift, shift=np.zeros(2), pixel=False)

Parameters:

Name Type Description Default
npixels int

The number of pixels in the output plane.

 required
pixel_scale float, meters/

The pixel scale in the output plane.

 required
focal_length (float, meters)

The focal_length of the lens/mirror this propagator represents.

 required
focal_shift (float, meters)

The shift in the propagation distance of the wavefront from focus.

 required
shift Array = np.zeros(2)

The (x, y) shift to apply to the wavefront in the output plane.

 zeros(2)
pixel bool = False

If True the shift value is assumed to be in units of pixels, else the physical units of the output plane.

 False
Source code in src/dLux/layers/propagators.py 
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def __init__(
    self: Propagator,
    npixels: int,
    pixel_scale: float,
    focal_length: float,
    focal_shift: float,
    shift: Array = np.zeros(2),
    pixel: bool = False,
):
    """
    Parameters
    ----------
    npixels : int
        The number of pixels in the output plane.
    pixel_scale : float, meters/
        The pixel scale in the output plane.
    focal_length : float, meters
        The focal_length of the lens/mirror this propagator represents.
    focal_shift : float, meters
        The shift in the propagation distance of the wavefront from focus.
    shift : Array = np.zeros(2)
        The (x, y) shift to apply to the wavefront in the output plane.
    pixel : bool = False
        If True the shift value is assumed to be in units of pixels, else the
        physical units of the output plane.
    """
    self.focal_shift = float(focal_shift)
    super().__init__(
        shift=shift,
        pixel=pixel,
        focal_length=focal_length,
        pixel_scale=pixel_scale,
        npixels=npixels,
    )

apply(wavefront)

Applies the layer to the wavefront.

Parameters:

Name Type Description Default
wavefront Wavefront

The wavefront to operate on.

 required

Returns:

Name Type Description
wavefront Wavefront

The transformed wavefront.
Source code in src/dLux/layers/propagators.py 
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def apply(self: Propagator, wavefront: Wavefront) -> Wavefront:
    """
    Applies the layer to the wavefront.

    Parameters
    ----------
    wavefront : Wavefront
        The wavefront to operate on.

    Returns
    -------
    wavefront : Wavefront
        The transformed wavefront.
    """
    return wavefront.propagate_fresnel(
        self.npixels,
        self.pixel_scale,
        self.focal_length,
        self.focal_shift,
        self.shift,
        self.pixel,
    )