We have just published our December 2012 newsletter and one of the subjects was the surface quality of copper mirrors prepared by Single Point Diamond Turning (SPDT).
We didn’t have enough room to feature all the data we have collected, but one customer sent us this mirror to investigate. They had noticed by eye the turning lines and “lay” of the surface machining marks. When used to reflect a red laser beam through 90 degrees, the scattered radiation illuminated the surroundings and the multi order diffracted beams can be seen as individual spots on the white screen above the mirror. Although far less in magnitude with infra red radiation the low order diffracted beams will cause heating of the surrounding mounts etc.
Since this medical laser manufacturer was using a red alignment laser this was not acceptable in any way. They now use our chemically polished gold coated mirrors where the surfaces are polished to an ultra-smooth UV grade quality.