This is my most recent Helium Neon laser acquisition. This is a very large laser, measuring 40" (102cm) long; it's rated at 35+mW and was sold to me as producing over 40mW.
There are some unusual features about this head, for a start the tube is mounted so that the Brewster windows are vertical rather than at 55 degrees to the horizontal as is more common. The second, more annoying, feature is that there are no fine adjustments on the mirror mounts, this makes adjusting the mirrors a very tricky job as the adjustments have to be made using the big hex nuts (see photographs below). The 'missing' mirror fine adjustments has a number of contributors to alt.lasers quite confused (me too).
I am in the process of adjusting the mirrors to peak the output, but, with my usual enthusiasm for cleaning windows (except when they are part of my house), I managed to split one of the sealing boots on the Brewster stems, so this has to be replaced first.
Pictures of the SP107C
End view of the HR mirror mount (click on the photo for a larger view)
Side view of the HR mirror mount (click on the photo for a larger view)
Bottom view of the HR mirror mount (click on the photo for a larger view)
Top view of the HR mirror mount (click on the photo for a larger view)
More pictures to follow soon.