Gaussian Beam Viewer

(A Processing program for visualising beam amplitudes)

Daniel Brown

summer project
2009

The applet below shows a 3D representation of the amplitude of a Gaussian beam. Using the viewer is straight forward: On the right hand side is all the necessary controls to alter the properties of the amplitude cross section are shown. The 3D view of the plot can be changed by clicking and dragging the image.

 
This applet has been built with Processing and makes use of the gwoptics plotting library and the. G4P (GUI for Processing) library.
Download the source code here: GBViewer_src.zip

The sliders can be used to change several parameters of the beam:
  • n-Mode – This controls the mode index of the beam along the X-direction (HG modes)
  • m-Mode – This controls the mode index of the beam along the Y-direction (HG modes)
  • p-Mode – This controls the mode index of the beam along the radial direction (LG modes)
  • l-Mode – This controls the mode index of the beam along the azimuthal direction (LG modes)
  • axis pos(Z) – This sets the distance you want to view the amplitude of the beam from the origin of the laser. Varying this shows how the amplitude dissipates over distance along the Z-Axis.
  • x/y range and z range – This setting alters the range of the X, Y and Z axes. With larger modes and axis positions you made need to alter these to get the best view on the graph.
  • auto Z range checkbox – Checked by default, this alters the Z axis range so that the graph extends over the whole axis length.
  • reset button – Resets everything to default.

The 3D interface provides two useful modes `perspective' and `orthographic'. Perspective is useful to view the graph normally as it provides a more natural 3D look. Orthographic view is best used when viewing the graph from the side, top or bottom as this give the view of a flat 2D amplitude representation. Provided are several buttons to quickly move to various positions and switch between viewing modes. To navigate the 3D graph you can use the left and right mouse buttons whilst dragging the mouse. Left button rotates the view and right button zooms in and out. For Mac users hold down the ctrl key whilst moving the mouse to zoom.

More information about Gaussian beams and the parameters in the equations shown in the applet can be found here.