Colleagues (again):

Ask and thou shalt receive!

I am now in receipt of a genuine photograph of a genuine failure of a glass lens in a metal ring mount.  It was in a laser cavity and failed (fractured) during high rep-rate operation.  The engineer avers that “there may also [have been] some stress concentration in the mount such as a burr or particle” but he feels they solved the problem by replacing the clamping ring with a fillet of adhesive.  Good show!

I pass this along to you because I know there have to be problems out there with ring-mounted glass lens assemblies.  I was beginning to think no one was reading my correspondence (and that hurt my feelings!).  Now that I feel better, I’ll stay out of your mailboxes for a while.

I also want to honor the engineer who sent this example in.  Broken glass is not pretty and sometimes it takes courage to talk or write about it.

Al H.
9-2-09