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2.5 Watt 532nm Laser for 400 dollars, what do you think?

Alaskan

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Atomicrox

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Alaskan

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LaserCo

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That's interesting, but the ad doesn't make it clear if that's supposed to drive a heater or a cooler load...
I have thought about that also, seeked controllers that had outputs for heat and cold which are not readily/cheaply found.. After watching (I think) Planter's videos of him firing up his dpss systems, I learn, that it is up to temp when it is rapidly flipping between heating or cooling.. an LED indicated this.. I would imagine one it is 'up to speed' with the flickering and settles out that you are up to temp.
 

Alaskan

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Update:

Here's a link with more information about these lasers, apparently, it is more common that they put out under two watts. See: LINK to Lightwave Electronics Solid State Lasers

Quote from the above link: Lightwave Electronics Model 246 Laser (Gallery)
The LWE-246 is a diode pumped green (532 nm) laser utilizing a laser head called the "Halfnote", apparently developed for the Alcon OPHTHALAS™ 532 EYELITE ophthalmic laser. Is utilized a side-pumped Nd:YAG rod in a rather overly complex and long (optics-wise) resonator. Information and photos of this laser engine can be found at LaserPointerForums Thread on Lightware Electronics Halfnote Laser. It is speculated that LWE had an excess of these lasers available after the Alcon contract terminated and the LWE-246 was the result. :) The label on the heat-sink says "Alcon" and there is no label on the laser head itself. This unit has serial number 0101 and I'll bet you any number of flying pigs that they didn't produce 101 of these. ;-) So, it may be a prototype. At the present time, there is no evidence that any others were ever built. And, there are no laser safety stickers anywhere to be found! So the LWE-246 couldn't have been a legitimate product.

This unit is a bit weak if it was supposed to be rated 2.5 watts. And the 1.8 W shown on the meter was only achieved after realigning the KTP doubler and HR mirror behind it, possibly masking an alignment problem elsewhere. But so be it. There were two RMA stickers inside (which have subsequently fallen off) indicating that it might not have been exactly healthy, but it is not known whether any repairs were done. In any case, to do a full alignment of the laser resonator consisting of five mirrors and the KTP is not going to happen. :)
These are still selling on ebay but at less than half the price I paid for my first one: EBAY LINK Lightwave Halfnote Green Laser Module w Heatsink 532nm | eBay

Word of caution, getting one of these playing is not a cheap or easy project, it requires a high current 2 VDC power supply with constant current regulator & TEC controller to keep the IR laser diode at the correct temperature. A second TEC controller would also be needed for the KTP to keep the crystal at the right temperature.

Due to the cost of the needed power supplies and regulators for the IR diode & TEC's, even if you get this for 100 dollars the project could end up being fairly costly. Might be better just to buy a 800mw 532nm Jetlasers and call it good unless you really need 1.75 watts of green, but to produce a decent divergence output, you might need to add some optics for the output too as I found the one I tested to have a terribly wide divergence, far wider than a multimode 520nm laser diode. That said, if you want a source for parts this unit has a nice 808nm pumped YAG in it which will put out a few watts of 1064nm. However, the YAG uses external OC and HR mirrors, so using the YAG to produce 1064nm for another project will also require the mirrors, how difficult it would be to get them mounted and realigned is something I'd like to know.
 

diachi

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Update:

Here's a link with more information about these lasers, apparently, it is more common that they put out under two watts. See: LINK to Lightwave Electronics Solid State Lasers



These are still selling on ebay but at less than half the price I paid for my first one: EBAY LINK Lightwave Halfnote Green Laser Module w Heatsink 532nm | eBay

Word of caution, getting one of these playing is not a cheap or easy project, it requires a high current 2 VDC power supply with constant current regulator & TEC controller to keep the IR laser diode at the correct temperature. A second TEC controller would also be needed for the KTP to keep the crystal at the right temperature.

Due to the cost of the needed power supplies and regulators for the IR diode & TEC's, even if you get this for 100 dollars the project could end up being fairly costly. Might be better just to buy a 800mw 532nm Jetlasers and call it good unless you really need 1.75 watts of green, but to produce a decent divergence output, you might need to add some optics for the output too as I found the one I tested to have a terribly wide divergence, far wider than a multimode 520nm laser diode. That said, if you want a source for parts this unit has a nice 808nm pumped YAG in it which will put out a few watts of 1064nm. However, the YAG uses external OC and HR mirrors, so using the YAG to produce 1064nm for another project will also require the mirrors, how difficult it would be to get them mounted and realigned is something I'd like to know.

Hopefully these are still around when I have some spare cash - I have two spare pumps and two KTPs that I could put into one of these.

It'd probably be easier to buy new mirrors and mounts if you intend to use the parts for another project. Would be much easier to align using some 3 axis top adjust mounts. But you'd also need to design the cavity if you intend to go that way. Easyish if you go for something linear, but it'd be more fun to build it out into a Z-Fold or something similar.
 

Alaskan

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Last month I bought two more from him and they came with the control board and power supplies, well, a lot more than that, see the photo below. I didn't expect the extras and the seller never mentioned he was going to give them to me, so I'm very happy with this :)



Although the control boards are there, they are so overly complex and due to missing the front control panel, I have great doubts I can ever get them working with the laser and will likely just use the DC power supply which is buried in a the lower section of the frame and interface a far simpler CC regulator and TEC controllers.
 
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diachi

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Last month I bought two more from him and they came with the control board and power supplies, well, a lot more than that, see the photo below. I didn't expect the extras and the seller never mentioned he was going to give them to me, so I'm very happy with this :)



Although the control boards are there, they are so overly complex and due to missing the front control panel, I have great doubts I can ever get them working with the laser and will likely just use the DC power supply which is buried in a the lower section of the frame and interface a far simpler CC regulator and TEC controllers.
That's awesome! Perhaps Steve (mixedgas on PL, LASERFAQ here) could help with creating an interface for the control board. Or Sam Goldwasser of the laser FAQ might know something.

Building a power supply shouldn't be terrible hard though, and there are plenty of TEC controller schematics out there too.
 

Alaskan

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I need some advice, I tried powering up one of my Halfnote lasers last night without having a TEC controller on the diode, I wanted to measure the output of the YAG and removed the output mirror to get a clean path to my LPM. I only measured like 50mw and then later nothing, even if I turned the current up on the diode feeding the YAG. The diode is good, I measured 18watts coming from it, so I suspect if you don't have the temperature of the diode set to give exactly 808nm output that this tiny YAG might become damaged, I don't see any damage, but is that what likely happened?
 

Alaskan

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Bump, anyone have an idea what the problem is?
 

diachi

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Bump, anyone have an idea what the problem is?
Do you mean the output mirror as in that 45 degree bounce mirror on the output?

Check the end faces of the rod for damage, and if you can look down the centre of the rod to see if there are any visible cracks. You should still see some lasing as long as you're within ~5-10nm of 808nm and everything is clean/aligned.

Edit: Keep in mind, all of the mirrors including the OC are HR@1064nm, so you won't see much in the way of 1064nm output if that's what you're trying to measure.
 
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Alaskan

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Oh duh, I think I know what I did wrong, you can't just put a LPM between the HR2 output bounce mirror and the YAG, both mirrors are needed for the output to lase and I kinda knew that, but somehow ignored that realty, this is all new to me. What I was hoping to do was use a section of the laser to get a few watts of 1064nm out, then use what components from this laser I need to make a simple DPSS 1064nm laser. Obviously, I'm tinkering where I probably shouldn't be messing with things and have the alignments all out of whack, even if carefully marking where the mirror mount was on the bed and replacing it? Won't put out any green at all now. :( HR2 mirror is the only one I touched.

 
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DashApple

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As you said all 4 of the mirrors are needed for the 1064nm to lase , you would have to reline the HR2 mirror so that is bounces the 1064nm light perfectly to the other mirrors ... other wise no green : (


You wont get any 1064nm from that laser as diachi said the optics will be HR@1064nm , You would need a OC made for 1064nm to have any chance of getting 1064nm out

With only the HR1 there is no cavity for the 1064nm to even lase .
 
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Alaskan

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So then, If everything is properly aligned, I should be able to put a LPM sensor between HR2 and HR3 to get 1064nm, or does it need all of the mirrors up to and including the OC to get 1064nm? Maybe that is what you mean by four mirrors? I oh so completely ignored the fact that the YAG and mirrors are a cavity needed to lase, I better open SAM's laser FAQ and get my act together understanding what is going on before tinkering. I am fairly certain I'm not following you very well yet on the OC needed for 1064, so will be exploring what that's about to just get 1064 alone.
 
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DashApple

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Yeah , I forgot to add OC in with the "4" mirrors bit : P

Mirrors HR1,2,3,4 and the OC all form the 1064nm cavity , without any one of them it wont lase at all .

Mirrors HR4 and the OC mirror form the 532nm cavity .

Without a actual 1064nm OC , there is no way to measure the 1064nm light as breaking the beam between any of the mirrors will stop lasing , the laser is 532nm so without optics been changed it will stay as a 532nm laser .


>>>>

Edit , ALL the mirrors are HR at 1064nm in that laser and as a OC isn't a HR mirror . The OC for a 1064nm laser ( any DPSS in most cases ) wont be 99% but something lower which will still allow the laser cavity to lase but also let some 1064nm light leave the cavity as a laser beam , that's what the OC is for and its reflectivity does partially depend on the gain of the laser cavity .

You can see in the image the yellow line is the 532nm cavity between the HR4 mirror and the OC , The OC lets some light leave this cavity as your laser beam , for the 1064nm laser the same needs to happen , but wont as there is only HR 1064nm morrs in the head .
 
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