odak.wave.quadratic_phase_function¶

A definition to generate 2D quadratic phase function, which is typically use to represent lenses.

Parameters:

Name	Type	Description	Default
`nx`	`int`	Size of the output along X.	required
`ny`	`int`	Size of the output along Y.	required
`k`	`odak.wave.wavenumber`	See odak.wave.wavenumber for more.	required
`focal`	`float`	Focal length of the quadratic phase function.	`0.4`
`dx`	`float`	Pixel pitch.	`0.001`
`offset`	`list`	Deviation from the center along X and Y axes.	`[0, 0]`

Returns:

Type	Description
`ndarray`	Generated quadratic phase function.

Source code in odak/wave/lens.py

def quadratic_phase_function(nx, ny, k, focal=0.4, dx=0.001, offset=[0, 0]):
    """ 
    A definition to generate 2D quadratic phase function, which is typically use to represent lenses.

    Parameters
    ----------
    nx         : int
                 Size of the output along X.
    ny         : int
                 Size of the output along Y.
    k          : odak.wave.wavenumber
                 See odak.wave.wavenumber for more.
    focal      : float
                 Focal length of the quadratic phase function.
    dx         : float
                 Pixel pitch.
    offset     : list
                 Deviation from the center along X and Y axes.

    Returns
    -------
    function   : ndarray
                 Generated quadratic phase function.
    """
    size = [nx, ny]
    x = np.linspace(-size[0]*dx/2, size[0]*dx/2, size[0])-offset[1]*dx
    y = np.linspace(-size[1]*dx/2, size[1]*dx/2, size[1])-offset[0]*dx
    X, Y = np.meshgrid(x, y)
    Z = X**2+Y**2
    qwf = np.exp(1j*k*0.5*np.sin(Z/focal))
    return qwf

odak.wave.quadratic_phase_function¶

See also¶