Initialize Laser Cavity
Drag source in between the two mirrors and watch the gaussian beam profile. Click on the a mirror to make it the active element. Drag the mirror to determine how far the mirrors can be apart from one another (with respect to their equal focal lengths) and the cavity still have stability? Drag the focal point next the the active mirror and observer the change.
Note: You can create a plane mirror (r=infinity) by dragging the focal point to the mirror position.