G2 problem

[RedCowboy]

I noticed my latest build all at once developed a heavy glare/fog around the beam.
All my cylindrical optics have a little artifact but this just went bad all of a sudden while burning wood.

I tore it down to find my cylindrical pair are ok, I knew about a couple tiny glitches on the large convex but I had focused in a clean area, then I noticed my G2 has a burn mark in its center.

I will post more pics and see if it cleans, but the way it happened suddenly was strange. Just all at once while running.

Someone else asked me if I had noticed anything different about the G2's and I have not.

This is probably something I did, maybe my UV glue outgassing deposited and later caused a burn on the G2, I will pull it and see, what was strange was the sudden fog around the beam, I was burning some wood and likely got some smoke/soot into the unit, it is the only one that is not sealed all around except the beam exit, so it could have had some air flow into the lens cavity that would bring in smoke.

Has anyone else noticed anything like this?

Is the G2 AR coated?

My other prior builds are fine, this one just went bad suddenly, but my others are sealed except the beam exit hole.

I found some AR coated windows at O-Like but their site is messed up, just glass not quartz but 2 dollars each for 12 and 14 mm rounds.

I think I will add expanders or telescopic reduction units or simply an AR coated dust window to my builds over 5w.

Again it's probably some contaminant I introduced somehow, but has anyone else noticed anything like this lately, I only ask because someone has asked me recently about it, but I have had no other problems and this was not sealed and used around a lot of smoke, as power goes up keeping optics clean and sealed will be important.

 

[DTR]

They are AR coated and yea it is possible to burn them if anything gets on the lens in the light path. Lot of energy running through a very small area.

 

[RedCowboy]

I will use an AR coated window and seal the builds from now on, I notice the projectors have sealed light engines to keep dust out, as power goes up it will be necessary.

Also a threaded in expander would seal the optics cavity.

 

[DTR]

Yep I do see instances of burnt windows and lenses at a much higher rate with the new highest power diodes than seen in the past. It will become more and more important as powers rise to keep optics clean. Might be worth looking at a little AR window that can be put in the focus rings between the ring and the lens to close the system off. If cheap enough wont matter if you burn them just swap them out.

 

[RedCowboy]

Well it cleaned up pretty good, it's still a good burning lens but I will use a fresh one for my rebuild.

That's a reflection of my camera in the lens, the bar shaped smudge cleaned off, but there are some light water spots at extreme unfocus, still it's a good burner.
Take a lesson from me if you don't already know fellow laser fans and protect your optics at 5W and above even airborne dust and smoke can stick to and burn on a lens.