Nd:YVO4 markings

[dsli_jon]

..Old crystal has been cleaned with medical isopropyl with lens tissue before fry-pumped so it is not an issue with a dirty facet

..Well, good friend - that was the point.. Isopropyl, 'medical-grade' or not, will leave a film, and thus can absorb-heat / re-burn.. even the thin layer of ablated 'coating', is not usually 'visible'.. we're talking microscopic-particles, here.. So.. not trying to 'pin the blame' on you - you very-well may be right in this case / it may have-had nothing to do with contamination, this time, but.. just sayin'.. For 'core-critical' components, like an SHG-crystal, spectroscopic-grade acetone is the way to go.. Gotta-remember, at the OEM, they're usually initially cleaning / installing these things in a clean-room...

..anyhoo, hope ya get it sorted..
cheers..
j

[Bbe]

Also important to pay attention to focusing of the IR beam. Point of focus should not be on the surface and should be a little deeper into the crystal. So that the area of ​​the pump power has been placed to the clear aperture of yvo4 crystal.

[absolom7691]

Old crystal has been cleaned with medical isopropyl with lens tissue before fry-pumped so it is not an issue with a dirty facet

A bit late to the party but Professor Steve has also posted (many times, I think) about not using alcohol for cleaning optics. He also gives a short list of safe stuff to clean optics with although, I am not sure which of those would be good for resonator optics vs table optics. Let me see if I can find that post.

[absolom7691]

Found the post:

I suggest, electronic, chromatograph, UHP, or spectroscopic grade from worse to best.

I strongly advise against hardware store grades for intracavity optics due to denaturalizers and other things added for various nefarious Gvnmt reasons. Either that or most makers don't care about crud in their stuff. When I worked for the university I quickly learned that 55 gallon barrels get relabled, and a hexane barrel today, is tomarrow's methanol barrel.
I should admit I mainly work on gas lasers with no gain and purity is a absolute problem.

In a real pinch, drug store 3% H202 (hydrogen peroxide) is very pure and can often bail you out with hard coated multilayers like dichros, but I would not use it on aluminized optics. The peroxide "eats" any organic in its bottle, so its a safe bet they have to make it pure to start with.

And for crying out loud, vodka is 1/3 potato, and while it is standard in Canadian optics cleaning kits, its NOT a good idea to use it on real optics.

Steve

[Bbe]

And my 5 cents ... Do not use a cotton swab or an old t-shirt to clean the optics. Only a microfiber cloth

[shrad]

cloth is OK, medical isopropyl might not I may have had some luck this time as YVO4 damage was prior and global, you could see coloration in the pump facet like with some overheated metal (small irised zone around the whole crystal)

but where to get spectroscopic grade methanol? I suspect I could not get it via a chemical store as not being corporate... I'll try to dwell further and ask some friends who are in the business

[planters]

but where to get spectroscopic grade methanol?

You might try a local college or university science dpt. If you keep the request to say 50 cc or less then they will probably not be too nervous that you will use this for a nefarious purpose and as far as inventory... this much is easily spilled or lost to evaporation.

[mixedgas]

Cloth? Microfiber towel? NO, use Lens tissue!
Thorlabs sells it cheap....

Nothing wrong with OPTICAL GRADE cotton swabs, either.

Steve

[Bbe]

Cloth? Microfiber towel? NO, use Lens tissue!
Thorlabs sells it cheap....

Nothing wrong with OPTICAL GRADE cotton swabs, either.

Steve

I mean OPTICAL GRADE t-shirts, cotton buds, etc and like these cloths
Cotton swabs usually leave after themselves a bit of fibers

[shrad]

I'll have a loot at this all, and get some decent stuff

My isopropyl is not medical as I thought, I got it via my pharmacy and it is reagent grade from the chem supplier, used for preparations... will this be OK? I did not see ANY strains on any optics I cleaned with it