FS: 355nm Q-switched UV laser

LASER IS NOW SOLD!!!

Up for sale is a fully functional 355nm UV laser made by "laser export". I had the laser checked over and tuned for optimal performance a while back by a laser technician. The laser is capable of receiving an external clock signal but is currently set to run on the internal oscillator at 200Hz. Instructions on disabling the internal oscillator and re-enabling the external clock will be provided. An external 24V 3A power supply is required to run the laser. A heatsink(a large block of aluminum will work) is necessary if you plan to run the laser for more than 20 minutes.

355nm is not considered ionizing and will not cause cancer but it's extremely eye unfriendly and can burn through several layers of skin. Since Q-switching is capable of generating kW pulses, eye protection is mandatory; You can get cataracts just from exposure to 355nm.



Lasing a Canadian $5 bill


Terms of sale:

I am asking for $275 USD plus shipping. Tracking and insurance is mandatory.

I am also selling this laser in good faith that the prospective buyer will use the laser as is. I don't want the laser torn apart for the components. Nor do I want it modified to output anything other than it's intended wavelength (355nm with some stray 532nm and 1064nm). I especially don't want it being purchased solely to be resold at a higher price; I am selling at a very low price to make it affordable to the average laser hobbyist.

In a nutshell, I would like to sell it to someone who can appreciate it's unique wavelength as opposed to chopping it up for parts or to get a more powerful green or IR. I would also hope than in the case you do part with the laser, you make an attempt to set a similar buyer criteria.

Obviously I can't legally control what the prospective buyer will do with the unit but I hope that a verbal promise can still hold it's own. I will not sell to anyone who intends to violate any of the conditions set above.

Due to the extreme dangers of Q-switched UV lasers, I reserve the right to restrict the sale of this device to those who I deem qualified/experienced enough to safely operate the laser. This consists of but is not limited to seniority, experience with lasers, general reputation, etc. This deal will be done at my discretion.

As always, first PM gets priority; if the deal falls through, the next person in line will get priority and etcetera.

Looks like a very cool laser, is 355nm visible at all?

Your terms seem fair as well, I hope you find a suitable buyer

On it's own, 355nm is a very dim whitish-violet; it's very similar to the color seen in the middle of the $5 bill picture. Due to it's short wavelength, it will fluoresce nearly anything.

As for my selling terms; I know it seems excessive but these lasers are quite rare now. Many owners tend to modify them to get a higher powered IR or green. IMO, they should buy a Q-switched IR or green laser instead of kludging one from a perfectly good laser.

Seems like a very unique laser. Question: Why would someone want to take a rare 355nm laser and modify it into a very common 532nm laser?

yobresal said:

Seems like a very unique laser. Question: Why would someone want to take a rare 355nm laser and modify it into a very common 532nm laser?

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To get the high(ish) average power and the high peak power of a q-switched laser at 532nm for cheap(ish).

Also, D_B I PMd you.

EDIT: D_B, I'd like to note that I have used UV lasers before, at higher frequencies than this too. My Omnichrome model 74 HeCd was a 325nm CW laser (It's actually pretty hard to tell on some surfaces!). So I do have some experience in that area.

How high are we talking here?

yobresal said:

How high are we talking here?

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Q-switching can put out kW pulses. Average power is only in the 10-80mw range.

yobresal said:

How high are we talking here?

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Do the math :

Assume pulse width = 7nS and pulse power = 20uJ ( Both possible with this laser ).
P=Power(W)
E=Energy(J)
t=Time(s)

P=E/t --------------E=20*10^-6J
--------------------t= 7*10^-9s

P=20*10^-6/7*10^-9

P=2.857kW

Pulse width on these can be as low as 4nS ... this would give you a higher peak power.

I have one of these - they're definitely unique but their usefulness is fairly low. They do pretty much the same stuff a 405nm laser does, but with a *barely* visible spot. It's also annoying to use due to the safety precautions. If you remove the knife edge on the final output part of the laser you will get three outputs - residual 1064nm, residual 532nm, and the normal 355nm output. (probably some 808 leakage as well)

The laser has two 4W 808nm pump diodes combined to excite an Nd:YAG crystal in a cavity with an AOM (the q-switch) the Nd:YAG charges up with energy since it cannot lase and then the AOM "opens" and allows the YAG to lase, dumping a large burst of energy. The large burst of 1064nm is frequency doubled with our good friend KTP, and then the second crystal rams a 532nm photon together with a 1064nm photon resulting in the final output of 355nm.

Removing the second crystal yields significantly more 532nm. Laser-Export is not happy that their lasers wound up on ebay and in hobbyist hands, which is presumably why he doesn't want people to modify or resell the laser.

Removing the second crystal yields significantly more 532nm. Laser-Export is not happy that their lasers wound up on ebay and in hobbyist hands, which is presumably why he doesn't want people to modify or resell the laser.

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I did not say I don't want people reselling the laser. I don't want the buyer to purchase it for the sole purpose of reselling it for a higher price. It's worth a lot more than I am asking.

As for modification, I do not want people tearing these lasers apart just to get a higher powered green or IR. It's akin to purchasing a rare vintage/classic car only to crop chop it into a "low rider". Brand new 355nm lasers cost at least $2k; beyond the affordability of most hobbyists, I'm selling at a lower price.

As for it's usefulness; it really depends on your philosophy of use. If you're the casual "I like looking at the beam and lighting stuff on fire" type, this probably won't appeal to you. If you're into building dye lasers, collecting odd lasers, illuminating minerals and such, you might find this unit suitable...

D'oh! Never even thought about using it to pump a dye laser! Could be used in an experiment to test for photoelectric emission from zinc. Could be used for some fun chemical reactions too I'm sure ... or glue curing.

I attempted to build a very crude dye laser with a quartz cuvette, cavity mirrors, and some rhodamine dye. It worked okay but was pretty finicky with the alignment of the cavity mirrors.

digital_blue said:

I attempted to build a very crude dye laser with a quartz cuvette, cavity mirrors, and some rhodamine dye. It worked okay but was pretty finicky with the alignment of the cavity mirrors.

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Yeah, it's easier if you have proper mounts. Would be a fun experiment to try though. IIRC that Rhodamine dye is toxic though?

Most laser dyes are toxic, you just have to be careful when handling them. This laser has a relatively low output power and very short pulses compared to a DIY nitrogen laser.

Well, it's back up for sale again, all prospective buyers backed out.

To people whom I have declined sales to, please don't take it personally. I had several people get really pissed over my decision. It's not my fault you don't appear to have any experience/reputation operating lasers of this nature; even if you were/are a world class laser expert, your posts have not reflected such and I am unable to make that call.

Think of it this way, I am selling you a device that spits out nearly invisible 3kW+ pulse 200-5k times per second. By the time you realize you've been hit, you'll be legally blind. Now, how would you feel if you knowingly sold such a device to someone who is potentially under qualified?

As much as I love rare lasers, I wouldn't want the risk... The price is great, but it's too dangerous of a laser -- and I have too many people in my house who may come and go. I considered PMing on it but thought better of it. I think the disclaimers and judgement are absolutely warranted. Hopefully it can go to someone who can give it the respect it deserves.

(Think about it. The last thing anyone needs is this thing shooting at a reflective/scattering surface, putting out kW pulses, -- your goggles fall off and you're scrambling around to find them while this thing is blasting away. Not a good scene.)

Really neat laser, but it has teeth....

(Now if someone was selling a working HeCd on the other hand...)