thesirc/modelling-gauss-beam-propagation-in-fiber

Modeling the focalisation of a gaussian beam through a cylindrical fiber interface with non linear absorption

Modelling focalisation of a gaussian beam through a cyndrical interface

Theory

The theory used to model the behavior of the beam is describded in P. A. Bélanger, "Beam propagation and the ABCD ray matrices," Opt. Lett. 16, 196-198 (1991).

Programming

Intuition of the program

The code computes each plane starting from the far left to the far right (the direction of propagation through the cylinder) and computes both direction independently (in calcul_x and calcul_y respectively). For each plane, it computes the field then the intensity. After getting the two intensity planes, a threshold (found experimentally for the sillica, 1/e^2 for the first version) is given to be used as the radii (semi-minor and semi-major axis) of the ellipse (in calcul_ellipse). Each ellipse is drawn to the 3D plot one after the other (again following the propagation direction).

Details

For further details on the implementation, please refer to the code which is commented extensively.

Results

You can find images (intensity and isometric view) from different angles (XZ plane, YZ planes) for different depths here.