Why some laser diodes have angled window?

Question

Why some laser diodes have angled window? Here is an example

score 5 · Accepted Answer · edited Jan 18 '24 at 20:42

The angled optical window is also called a Brewster window and it has two functions:

Virtually eliminating or greatly reducing the light being reflected back to the laser by utilizing Brewster's angle, in order to prevent interference with the operation of the laser.
Maximizing the amount of light exiting the laser diode by using Brewster's angle and thus eliminating losses associated with back-reflections from the surface of the optical window.

Brewster windows are also used in other types of lasers such as for example He-Ne laser.

1 Answers1