80 watt YAG - I broke it - Do'h

[Laserman532]

Simon,

I agree that what you describe sounds like an engineering flaw. This unit for all its power is still a lamp driven YAG and so it seems that the perfectly adequate single closed loop DI cooling scheme used for the 40 watt'ers should work for this as well. Allowing you to eliminate the hook up to tap water would make this a lot more portable too. If really good water quality is needed then increasing the volume and more frequent flushes should help.

I will come out of retirement for a while to help you "not so old" people.

Yes...you will need a minimum of a 4kw affinity all stainless steel chiller with closed DI recirculator (for extended operation as in a permanent installation I would recommend a 6KW) depending on the ambient air temperature of the installation.

I respectfully disagree - it is not a design flaw...it was designed as how it was intended to operate...for the most part these lasers were designed to "idle' (90% of the time) for hours prior to an operation...then a burst of current to burn that vag. If you plan to operate this cavity design for more than a few minutes (at any current over 30 amps)...you will need to increase the volume of water resivor to at least to 2 gallons of recirculating DI water (to compensate for the slow but sure rise in temperature). To remove the heat via a water to air heat exchanger you will need a minimum of a 4' x 4' area of a stainless steel heat exchanger with a minimum of 4 - 12 inch fans...or a stainless steel water to water heat exchanger capable of 2 GPM @ 40 PSI.

as said in signature...been there done that...so forth so on...

as to the other rookie mistakes he made...

The laser is Not a CW laser...yes you can run it CW....but your first failures will be the OC mirror bleaching and the secondly...the coatings on the end of the rod will start to delaminate from the outside working towards the center of rod (on a cavity based on all HR mirrors there is too much circulating power for the coatings to handle)

If he was running green and green stopped (and the lamp still operates normally) it is always a rod problem (either broken or water on ends due to o-rings leaking, which can be caused by removing the qs and misaligning the beam enough to burn the rod o-rings)

Even if KTP is BLOWN...if there is ANY available IR to meet threshold of lasing...it will emit a scattering spiderweb of some green light (a butt ugly beam, but there will be some green).

He removed the QS - not good...IR is aligned with QS installed and it basically has ZERO insertion loss

He dittolled the optics trying to find the beam...not good....(horse before cart) Now you get the experience of starting alignment from the beginning! (OBTW you better have a 2% OC alignment mirror or you are wasting your time...you will NEVER get green you want if the IR isn't there.

Photonbeam is correct - a cheap rod without the proper coatings will not yield the IR necessary to produce the specified IR prior to doubling

Same thing goes for crappy KTP - you are wasting your time with cheap KtP

I would also stop calling it a 80 watt laser until he can show 80 watts on a power meter...I don't mind him saying..." man with 18 inch dick has 80 watt laser" tho... I have a REAL problem people claiming something a laser...frankly...is not...those are called "marketing watts".

Once you have done what has been done...you will never see 80 watts out of it again until all components are brought up to "factory standards"

But I could be wrong

[absolom7691]

Jesus, Pat... 95% of what you just typed went over my head! This is why I would never own a LS and also why I would take heed to what my "elders" have to say. Damn shame though. I would like to see 80W of green coming out of this beast.... Good luck!

[planters]

Laserman,

Sound advise. It's my understanding that the quirky thing with these least-old/newest LS evolutions (vs 80 watt'ers) is that they normally are tethered to a fresh water source and use it as a DI/RO input to renew/regenerate the small quantity of DI water in the system and they tap into this source many times per hour.

It seems to me that the input power to the lamp with this laser is similar to that of the older 800 series. What about grafting the newer optical system onto the robust self contained cooling system of the older model? Alternatively, your statement that these were designed more like QCW medical lasers suggests that maybe these are not that different than the older models, but that they are driven harder, require tighter cooling management and not until you get to the diode pumped models does the substantially higher power of the later evolutions appear.

[Laserman532]

@ planters ---- Sorry I had to EDIT here --->you said DI / RO tied to house...and I read right over that...I have never seen these new so called "but burners" and was not aware that they made their own DI via RO or whatever the Eff it is...never seen one...they are way after my time...sounds like a good idea...but they need more volume of H2O to operate at longer currents for longer times... S

most of them came with a military grade stainless steel water to water heat exchanger and were tied to fresh water. For other models that were lower duty cycle / power units came with a 2.2KW stainless steel water to air heat exchanger.

"What about grafting the newer optical system onto the robust self contained cooling system of the older model?"

I would not do that IMHO... that would be taking something cool and putting on a smelly, smoking wart piece of crap vag burner...NO one in their right mind would do that!!!

They should probably do something like this...

http://www.photonlexicon.com/forums/...ight=cobra+yag

Or that little project I did 28 of prior to the Cobra...something called The UltraRay... those babies are still floating around that have been converted from smart to dumb (don't get me wrong...building it dumb was much more smarter)

The Cobra was the top of the line in design...however TOOOOO complicated and all digital.... You just need a switch for the lamp driver, current knob, and a switch for the QS...and a chiller...life be good. Sometimes us engineers are too smart (so we think). KISB - Keep it simple bitches...

[planters]

@ planters ---- Sorry I had to EDIT here --->you said DI / RO tied to house...and I read right over that...I have never seen these new so called "but burners" and was not aware that they made their own DI via RO or whatever the Eff it is...never seen one...they are way after my time...sounds like a good idea...but they need more volume of H2O to operate at longer currents for longer times... S

My thought exactly. And if the volume was high enough then the continuous umbilicus to the sink might be skipped.

Thanks for the link. Interesting things were happening long before I entered this hobby.

I don't know if the optical system in the newer models is better or worse than the 800's. I'm not equivocating. The 800 I own has some pretty nice engineering and maybe the newer models built on this or maybe they cut corners. But, I am curious as to how they were able to extract 80W vs at best 45W from roughly the same lamp current. I know the gain with these things is not linear (it isn't even a fixed slope). If the thermal lensing were tamed and the doping was adjusted then I wouldn't be surprised if they found more efficiency.

You call them butt burners, but I thought the big market for these was for prostate resections.

I really don't prefer digital for practical tools. Take the venerable SLR camera. The older, multi-knob/lever model could be adjusted, focused and triggered without taking your eyes from the subject. Now, (probably because it is cheaper to manufacture) you have to select from a menu of choices (or even a menu of menus) while the creature dives back under Loch Ness.

[Laserman532]

I have never seen one...this 80watt thing has me baffled. can you turn it on, poke it in a power meter get it to read 80 watts then go out to dinner and come back and it still reads 80 watts? What is the q switch frequency set to get that...I think if you run it towards 12khz you get more power, what is the lamp current 40A???, it looks like the cavity is different, better ceramics, may be better doping, better kip, better temp control of kip, better water temp control, better flow...it could be a lot of things...the optical relay looks the same to me.

My lasers UltraRay and Cobra would do 40 + real watts of 532 at 20khz for hours.

I hope you guys realize that 80 watts is not the record for the optical relay...I think over 120 watts of green was demonstrated by Kuizengua (& i think Bass at LLNL if memory serves me correctly) in a dual yag cavity design. (the patent is available if someone has the knowledge to dig it up - look for dual cavity optical relay by Kuizengua or something like that)

anyway...once you pass 40 watts...the rest is just for show and bragging rights... I pursued the yags because I hated hauling 171's around.

Photonbeam called a it "prostate burner" to differentiate between Simons unit and a "Vag Burner" I shortened it to "Butt Burner" I ASSumed that is the portal they used to access the prostate...It is a long way the other way. I call the old mr coffee type roll around medical units "vag burners" because they were used to remove venereal warts and they all smelled like burnt skin.

Then there was the Ultra Ray and Cobra by me and the Infinity 2000 by Laser Fantasy...and then a shitload of "conversions" of vag burners.

Where is Simon???

[Photonbeam]

But, I am curious as to how they were able to extract 80W vs at best 45W from roughly the same lamp current. I know the gain with these things is not linear (it isn't even a fixed slope). If the thermal lensing were tamed and the doping was adjusted then I wouldn't be surprised if they found more efficiency.

You call them butt burners, but I thought the big market for these was for prostate resections.

I've often wondered the same. My best 700 series 'scope did 67W (for awhile). No free lunch... so, maybe bigger beam + bigger divergence = more power? It's all going into a large fiber anyway. We know the flashlight beam of the 800's was pretty much unusable for lightshows. That's why we all had to improve the collimation when modified for light shows and even then it's pretty huge.
Pat's right, all the surplus 'scopes I owned smelled like burnt skin - a smell I know well. When I worked as a tech in laser surgery, my job, besides calibrating/operating the lasers and taking photos, was handling the fume exhaust. Like a shop vac hose with a drop-light housing on the end to keep from sucking up sponges, etc. The types of surgery we did including vaginal warts, cancer tumors and excision of necrotic tissue from burn patients produced massive amounts of smoke which I could (can) still smell. If I could smell it, even through a surgical mask, that means I was inhaling the burnt tumor cells. No one seemed concerned about that. This was the early '70's and as far as I know, I don't have cancer (yet) - knock on wood. Later, I worked at Spectra Physics handling laser dyes with no gloves or mask..haha..
When all we had were SP171's, Pat really changed the industry by introducing the q-switched doubled yags. Thank gawd the pros today have pretty much moved on to multiple CW laser diode Arctos-style arrangements or OPSL to achieve high power - and more color. Now those old q-switched medical yags are coming into the hands of hobbyists for a few hundred dollars - yikes! If some kid can disorient a 777 pilot with a handheld laser pointer, what could he do with a 'scope in the driveway plugged into his mom's clothes drier outlet in the garage? At least if someone tries it they won't be hard to find. The FAA takes this very seriously and they WILL find you.

[gashead]

Photonbeam called a it "prostate burner" to differentiate between Simons unit and a "Vag Burner" I shortened it to "Butt Burner" I ASSumed that is the portal they used to access the prostate...It is a long way the other way. I call the old mr coffee type roll around medical units "vag burners" because they were used to remove venereal warts and they all smelled like burnt skin.

Another name has been coined in the UK (Yah'all know we like to make our own terms up for things) the general catch all term for Scopes are "Cu*t cutters" I also refer to the dust and fluff that resides inside the units as "Fanny fluff" (I know, Fanny means something else here).

However, if I ever manage to kill a rod at least I now have a great idea for an expensive pair of earrings for my wife... Thanks Pat!

N.

[gashead]

Now those old q-switched medical yags are coming into the hands of hobbyists for a few hundred dollars - yikes! If some kid can disorient a 777 pilot with a handheld laser pointer, what could he do with a 'scope in the driveway plugged into his mom's clothes drier outlet in the garage? At least if someone tries it they won't be hard to find. The FAA takes this very seriously and they WILL find you.

I would hope the barrier to this is the logistics of it all.. As you chaps well know a 800 series (for instance) weighs.. erm quite a lot! I've hurt my back lifting one out of a van (and there were four guys helping me, one suspects we are weaklings).. you then need the space to store it etc, the utility to run it.. yadda.

I'm 37 (I could be 38.. I loose track) have my own home and workshop.. have been involved in the Lasershow industry since I was 17.. have two project Laserscopes but they sit.. unloved waiting for me to find the time and money to finish the conversion.. ever time I fire them up I'm aware of the hazards involved.. not just the output you have to worry about.. the HT also has me heightened, but perhaps it's my awareness of the awesome dangers involved that produce that output beam that keep me safe. This is what you get from growing up with Ions. I often wonder if those who's first experience with Lasers was diode based don't understand the risks?

I would hope after the Pro DJ fiasco people have learnt their lesson ?


Probably not.

[Laserman532]

anything can break in these lasers at anytime, the correct parts are expensive and difficult to source, you must have spare parts on hand at all times, I carried a spare parts kit worth $5K and could flip a rod in in 30 minutes, spare parts will be impossible to come by in the future, any part you break makes the machine nothing but a big ass boat anchor. Very few people have the knowledge & financial abilities to keep one running correctly, less on a fleet of them. At one point in time I had $20K in spare rods and KTP's, Q Switches, Lamps & optics sitting on the shelf to support my base...it was a true nightmare...

I feel sorry for Simons plight - but he has done nothing but taunt me about these lasers... I use to think that, if the student hasn't learned...the teacher hasn't taught...I try to teach, but some refuse to learn.