8.1.1 Laser

1. Set the interferometer base on a lab table with the micrometer knob pointing toward you.
2. Position the laser alignment bench to the left of the base approximately perpendicular to the interferometer base and place the laser on the bench.
3. Secure the movable mirror in the recessed hole in the interferometer base.
4. Turn the laser on. Using the leveling screws on the laser bench, adjust its height until the laser beam is approximately parallel with the top of the interferometer base and strikes the movable mirror in the center. To check that the beam is parallel with the base, place a piece of paper in the beam path, with the edge of the paper flush against the base. Mark the height of the beam on the paper. Using the piece of paper, check that the beam height is the same at both ends of the bench.
5. Adjust the X-Y position of the laser until the beam is reflected from the movable mirror right back into the laser aperture. This is most easily done by gently sliding the rear end of the laser transverse to the axis of the alignment bench.

You are now ready to set up the interferometer in any of its modes of operation.