Swapping out the arc lamp for Laser diodes in yag laser

[blown350]

On A Laserscope KTP 532 system, is it possible to change out the arc lamp pumping for a simple laser diode pumping of the yag rod? also would this require any changes of the optics or mirrors. The idea is to get lots of green output. If it is possible to do this what do you think would be needed for pump power (watts of 808nm)? All this is for a common 30 watt laserscope. Thanks Sean

[Laser Zone]

Howdy Sean !! I was told by some dude that you would need around 100 watts of 808 , if I remember correctly . I dont know if this is true. Im sure the laser gods will chime in soon and give you the full run down !

[mixedgas]

you might have issues with the change in thermal lensing, where the outside of the rod expands more then the inside and you get distortion of the rod faces. If the cavity compensates for that, you have a issue.

Two or three guys analysed the laserscope cavity here a few weeks ago and they might have something to say. Weartronics and LesleQ I belive.

Steve

[Laserman532]

i would not take that approach, the cavity design is not correct...i would purchase a running 1064 diode pumped head with power supply and stick it in the optical relay...but hey...that is just me.

[weartronics]

On A Laserscope KTP 532 system, is it possible to change out the arc lamp pumping for a simple laser diode pumping of the yag rod? also would this require any changes of the optics or mirrors. The idea is to get lots of green output. If it is possible to do this what do you think would be needed for pump power (watts of 808nm)? All this is for a common 30 watt laserscope. Thanks Sean

Hi Sean,

Others have considered this too, but I haven't seen such a conversion done yet. By its nature, the optical relay will operate with a wide range of thermal lensing in the rod, so you may be able to use the same optical components. But I doubt you would be successful with a blind plug-and-play conversion. If you search for Laserscope patents by Kuizenga, you will learn about the design of the resonator including the typical 1064nm resonator power and 532nm conversion efficiency. I would not recommend attempting this conversion until you understand the design of the Z-fold resonator very well, because there are many factors to be considered.

Also, consider the cost of this conversion versus what is to be gained. Unless you have a very good source for surplus pump diodes, and you are competent to design your own pump chamber and diode driver, the Laserscope machine will be the cheapest component in your design. Though the electrical requirement will be reduced, the result is still physically very large, and the pump diodes, YAG rod, Q-switch all still require water cooling with a radiator or compressor (it is not economical to use TEC for such high power pump diodes). In my opinion, it is not worthwhile.

If the electrical requirement of the Laserscope machine is too much, I suggest you search for a more recent machine e.g. Laserscope Aura which is already diode-pumped. You can also consider Coherent Verdi, Spectra Physics Millenia or similar lasers, which have much better beam quality, but they are rare on the surplus market.

If you understand the design of the Z-fold resonator very well, and you are familiar with principles of optical design, and you have a lot of spare time, then you can build your own green machine based on any 1064nm laser. But if you place any value on your time, it becomes much cheaper to buy a machine which was green from birth.

If you have any more specific questions, I am pleased to help if I can.

Best regards,

weartronics

[GooeyGus]

Throw one of these lil' guys in there....

http://cgi.ebay.com/50W-Diode-Pumped-Nd-YAG-Laser-Modules-DPSS-laser-head_W0QQitemZ270275445986QQcmdZViewItemQQptZLH_De faultDomain_0?hash=item3eedac04e2&_trksid=p4634.c0 .m14.l1262&_trkparms=|301%3A0|293%3A1|294%3A30

That is a 50W model, but they sell a 100W model as well. I'm sure 100W of 1064nm light must be pretty close to the amount that the arc lamp setup pumps out.

There might be 1,000 reasons why something like this wouldn't work (such as the reasons listed by weartronics), I honestly dont know enough about the laserscope setup to give a firm answer, but it looked like a potential option.

[Laserman532]

It dosnt make any sense to modify a perfectly good design...Lamps are about $175.00 a rod is about $750.00. Time to convert it and make it work...PRICELESS

[GooeyGus]

It dosnt make any sense to modify a perfectly good design...Lamps are about $175.00 a rod is about $750.00. Time to convert it and make it work...PRICELESS

Yeah exactly... unless you had some really really strict power requirements (such as only 120v 20A etc, in which case i'm sure a bunch of the electronics would have to be changed as well... what a pain) there wouldn't be much of a reason to swap to diode when it works just fine with the lamp setup.

If it aint broke, dont fix it!!

[frothychimp]

About the only thing you would not be replacing is the KTP, and maybe the cooling system. You might even salvage some of the optics but to pump YAG at very high power does not really lend itself to end pumping. As such you will need to side pump so the links above for a complete diode and YAG rod setup would be useful. The HR might be useful but the OC probably will not be for optimum efficiency. You will need an OC with proper arc designed around the length/width of the rod for maximum active area keeping in mind the separate KTP within the resonator. Can you do a z-fold resonator with the diode pumped chamber as listed above? You bet, but remember every optic is designed for characteristics to maintain high energy within the resonator and minimal walkoff. With the change in pump chamber requires a change in distances between the optics or even the replacement of some of the optics depending on the beam characteristics of the new 1064nm laser head. Now scrap all the high voltage/high current electronics to drive an arc lamp and replace it with a diode driver. If you are still using the cooling system then you will have equipment cases for both types working together in a jumble of wiring. My guess is an upgrade to diode pumped will run a conservative $4000 USD figuring a 100W YAG laser head (using all eBay components). Thats a lot of arc lamp replacements or the purchase of several very nice, used laser systems. This would be quite a challenging project. Not impossible, but quite challenging and you would need to come to the realization that what you end up with may not be as powerful or even work.

[mixedgas]

Hey pat, how much gren would 35 amps of arc get him? If he migrated to a ESKI supply which would run off single phase 220 ?

Steve