Nd:YVO4 markings

[dsli_jon]

...I did not see ANY strains on any optics I cleaned with it

..try gently 'huffing' on it (..like, when you breathe on a window to make 'steam' / write in it, etc..) then look at it against the light.. you'll see *all* your cleaning-tracks, and the fatal burn-spot, real-well..

RE: 'is it ok' - If alcohol, of any-quality, were acceptable, it would already be well-known / in every SHG-cleaning kit / 'how-to' section, in every service manual in the world.. but... it's not. ..and for a reason. Honestly, you'd be better-off using 'hardware store-grade' acetone, run thru a coffee-filter, into a clean-glass bottle, and the 'wooden-tip' cotton-swabs you can buy in a camera-store, than 'pharmacy alcohol'... fine for cleaning buttocks, not for SHG-crystals... jus' sayin'...

.02
j

[Bbe]

Sorry guys, I could not refrain

kvantiasho in Ibiza http://www.viasho.com/c49378.jsp

a-ha-ha...

I understand that this post is off topic and I apologize for spam ))

[shrad]

when huffing on it and looking at strains with halogen light at an angle, I see nothing... and I have good eyes (even with a 15X large aperture magnifier I see no strains)

[mixedgas]

My newer practice,
This fits with what I have told people in the past, except the Ethanol is a new idea for me.
The lasers I work on are now Joule level, Picosecond pulses. Small pieces of dirt/lint on the optics cause expensive mistakes.


In order of desired use:

For glass/fused silica/quartz optics:

1. Hand driven, specially cleaned, filtered, Rubber Air puffer.
2. UHP, Chromotography or Spectroscopy grade Ethanol
3. UHP, Chromotography or Spectroscopy grade Methanol
4. UHP, Chromotography or Spectroscopic grade Acetone

For most Non-linear crystals

1. Rubber Air Puffer with filter.
2. Dry UHP grade Ethyl Acetate certified to have no water content.
3. Dry UHP grade Butyl Acetate certified to have no water content.

Cleaning materials:

Specially inspected and company approved, supplied, lens tissue using:
A, Drop and Drag method.
B. Hemostat if there is no way to drop and drag.
C. Specially graded, company supplied, optical swabs as applicable.

1. In a emergency, remember that Thorlabs buys its tissue from what used to be the Kodak tissue plant and is the only acceptable brand in emergencies.
2. Do not use camera store tissue, chemicals, or water/ammonia/detergent based cleaners.
3. Use of optical/photographic cotton gloves and or semiconductor grade finger cots is to be considered.

Other rules:

0. The laser is designed so the optic never gets dirty.
00. The whole laser or crystal oven(s) is/are heated when on AND OFF to keep humidty out and the resonator stable.
000. If air flow is needed, find another way to cool the widget.
0000. Water cooling to a heat exchanger is Good.
00000. No freon driven air cans are to be used. Dry filtered nitrogen is acceptable as a last resort.'
000000. Peel off film cleaning is for consumer grade optics only, do not use intracavity.

There are some really advanced techniques available for optics production, ie reflux still, plasma cleaning, dry hydrogen baking, etc.

Grazing incidence lighting from a diffuse but bright source 3-5 meters away is preferable to the "breathing on the optic" method.


Steve

[shrad]

is grazing incidence from a halogen lamp several meters away good enough for such cleaning? I'd never have though is was such a reliable check... sometimes the most simple approach is still the best one

my isopropyl is not water free so not to be used on soluble crystals, but would is be OK with things like YAG or Vanadate which are not hygroscopic?

thanks for this input Steve, this is really nice to know

I'm still waiting for a quote for small quantities of the chromato rated chemicals from a friend, but the cheapest source us 45€ per half liter (which would be contaminated before I have drink the half)

[planters]

Shrad,
You seem to be resisting this advise and negotiating for the use of your isopropyl alcohol. I think you should spend the 45E x 2 and get the lens tissues and keep everything covered when you are not working with it. There are a number of other challenges you will need to face in order to get the most out of the vanadate I would minimize the risk of dirty optics.

[shrad]

I'm not resisting... I just haven't the cash to spend right now and want to be sure the isopropyl alcohol in itself is not a too bad alternative

I'm repairing those heads to raise cash and I'd prefer not to invest too much for it beforehand... be sure I have Steve's list stuck inside my head, but there are too many concerns nowadays (bills to pay, car to feed and a baby's coming, so non-trivial things come first)