Laser Cleaning

[premierlaser]

Hey Guys,
Whats the best alcohol to use to clean optics with? Also what type of lense paper should be used?

-Adam

[300EVIL]

Hey Guys,
Whats the best alcohol to use to clean optics with? Also what type of lense paper should be used?

-Adam

I like reagent grade acetone and/or methanol. However, you may want to make sure the possible coatings on a particular optic can handle the solvent of choice before cleaning.

Here are a few good links...

http://www.photonics.com/Content/Rea...rticleID=24578

http://www.edmundoptics.com/TechSupp...?articleid=265

http://www.thorlabs.com/NewGroupPage...ctGroup_ID=330

[Jem]

Pure Isopropyl Alcohol... Be wary of using acetone as some coatings don't like it. Even worse is if your lens is in a plastic holder you're quite likely to dissolve it with acetone.

There are many ways to use Isopropyl alcohol as a cleaner and opinion differs (and always will) on which way is best.

If you can remove the lens that needs cleaning from its host, it's probably best to rinse under plain running tapwater to remove any big particles. Then you can take a piece of tissue and lay it across the lens, put a few drops onto the tissue to ensure it's well soaked and then slowly drag the tissue off the lens. Do not touch the tissue as its being dragged off. Let the alcohol evaporate off the lens naturally. Repeat as necessary.

Alternatively you can use a similar method but substitute a microfiber cloth instead of tissue. Note that the cloth MUST be immaculately clean.

As i've said there are many ways to do this and others will almost certainly say that the above is the wrong method. All I can say in my defence is that i've worked in the optical sector for more years than I care to remember and i've yet to ruin or scrath a lens using the above method.

Another absolutely BRILLIANT way of cleaning lenses is to use one of the new polymer lens cleaners such as opticlean. To be honest I think this would be my preferred method of cleaning laser optics as they can easily be done 'in-situ'. You literally just paint this stuff on your lens, let it dry and then peel it off. It takes all the dirt with it when its peeled off and leaves your lens pristinely clean.

If you send a PM to Stanwax on this forum he a UK agent for opitclean products. It is quite expensive, but a small bottle of this will last you ages.

Cheers

Jem

[shrad]

isopropyl alcohol is also usually mixed with 50% ether to help evaporation

methanol is also mixed with isopropyl alcohol to help dissolve sebum and greases like oil vapour or tobacco tar deposits

the best thing is to avoid things like acetone like 300EVIL said, as you never know if the coating will like it

the rest is a question of experimentation, but a common rule is to never use the same area of your cloth or lens paper two times at the same place, and avoir repeating movements in the same direction... the lens likes when you draw the tissue in a straight way from left to right, and then repeat the movement with some degrees of rotation and a different zone of the tissue

also, don't put too much of the cleaning mix on the paper/cloth/tissue as it could result in less efficiency on cleaning and evaporation traces...

[Diachi]

Also , just to add.

You CANNOT use common optics cleaners, like acetone and isopropyl, on ZnSe optics, as ZnSe ( CO2 laser optics ) dissolves with these. So you need to buy special CO2 optic cleaner.

Regards,

Adam

[mixedgas]

Isopropyl is evil on intracavity argon optics, it polymerizes sometimes. In that case, methanol

Steve

[GooeyGus]

I stick to 99.8% methanol

[mixedgas]

I stick to 99.8% methanol

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

[GooeyGus]

The stuff I use is about $200/liter and is specifically for laser optics. I forgot to read the actual grade on the bottle... I know it comes packaged under nitrogen (but I'm sure they all do... this is just the only stuff I ever really see) I use it at work to clean the retro-reflectors on our metrology equipment and the scanner mirrors on our 'tracing' systems. Good stuff!!!