Laser Alignment
It is often useful to align a laser beam so it is centered over a row of holes on an optical
table, and at the same height as the optics being used. This is easily achieved with a
few simple steps. You should have a plastic ruler marked in inches (our optics all have
a 3” center height). Note that the ruler has a heavy line running near its centerline.
1) Position M1 near the edge of the table so it deflects the beam at a 90 degree angle,
and securely bolt it down.
2) Using the ruler, adjust the upper knob on M1 so the beam passes over the target
row of holes at a height of 3”.
3) Position M2 so it deflects the beam by another 90 degrees AND so the point where
the beam hits it is above the target row of holes. It helps to look down on the mirror
from above. You will probably find that there are no mounting holes where you need
one, so use an L-clamp to hold it in place.
4) Hold the ruler upright on its short edge and center the heavy red line over a hole
near point B. Use the control knobs on M2 to adjust the beam to hit the ruler at the
3” mark on the heavy line.
5) Move the ruler to point A, again centering it over a hole. Use the knobs on M1 (not
M2!) so the beam hits the same spot on the ruler.
6) Move the ruler back to point B and note that the beam has shifted. Use M2 to
readjust.
7) Repeat steps 5 and 6 until the alignment stops shifting. Usually only one or two
iterations are needed. Remember that when the ruler is at point A you adjust
M1, and when it is at point B you adjust M2.
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