Source code for lasy.propagators.abcd
import numpy as np
[docs]
class ABCD:
r"""
Class that defines and manipulates ABCD ray matrices for an optical system.
Parameters
----------
abcd : 2d array
The 2D ray matrix of the optical system through which the beam propagates.
By default, this is initialised to be the unitary matrix:
.. math::
O =
\begin{pmatrix}
1 & 0 \\
0 & 1
\end{pmatrix}.
"""
def __init__(self, abcd=np.array([[1, 0], [0, 1]])):
super().__init__()
self.abcd = abcd
[docs]
def add_vacuum(self, distance):
r"""
Add a propagation over a distance :math:`z` in vacuum.
Parameters
----------
distance : float (in meter)
The distance in free-space which the beam propagates.
The ray matrix for propagation of a distance :math:`z` in vacuum is:
.. math::
O =
\begin{pmatrix}
1 & z \\
0 & 1
\end{pmatrix}.
"""
vacuum = np.array([[1, distance], [0, 1]])
self.abcd = np.matmul(vacuum, self.abcd)
[docs]
def add_lens(self, focal_length):
r"""
Add a thin-lens with a focal length :math:`f_0`.
Parameters
----------
focal_length : float (in meter)
The focal length of a thin-lens through which the beam propagates.
The ray matrix for propagation through a thin lens with focal length :math:`f_0` is:
.. math::
O =
\begin{pmatrix}
1 & 0 \\
-1/f_0 & 1
\end{pmatrix}.
"""
lens = np.array([[1, 0], [-1.0 / focal_length, 1]])
self.abcd = np.matmul(lens, self.abcd)
