A project log for Building Another Laser Cutter

Building a laser cutter around a Coherent GEM-50L laser

Jerry BiehlerJerry Biehler 02/13/2021 at 22:250 Comments

I got the optics mounted. They are attached to an aluminum stud which mounts inside the mirror block. Machined a fixture out of scrap plastic to get everything aligned. After that I coated the optics with a special polymer optic cleaner that is also good for storing optics. 

There are two normal gold plated silicon mirrors, one phase retarder and one ATFR. The ATFR and the phase retarder are what make up the cut cut enhancer. The ATFR reflects in s-polarization and absorbs the 90degree off p-polarization. The beam is reflected off this and hits the phase retarder which converts linear polarized light into circularly polarized light. When this hits something reflective when cutting the beam bounces back and is converted from circular to p-pol which gets absorbed by the ATFR.

Since the ATFR can absorb several watts I made a custom holder that uses some silver heat sink paste and a couple springs to hold the mirror in place against it.