Deep UV CW laser

[MrAnders]

Hello I'm new at the forum.

I've searched the internet for information about a Deep UV CW laser. I need such a laser to do Raman spectroscopy on a Renishaw machine. I was thinking to use something like the LEXEL™ 95-SHG LASER, but i guess it is out of my price range (maybe 1000 to 5000 $).

Does anybody know if it is possible to get a 244 nm CW laser in this price range (Used is fine). I guess I need 10 - 50 mW at least to run with my system.

Maybe my question is rediqueless, but I don't know much about lasers...

 

[KGB_Productions]

Head over to photonlexicon.com They will be able to help you better.

 

[anselm]

Since when are invisible wavelength UV lasers used in show projetors.... :thinking:
You might wanna read the appropriate section of Sam Goldwassers repair FAQ.

 

[KGB_Productions]

photonlexicon is not only scanners but the largest forum for Medical and Gas/Ion lasers also. There may be 100X more members here BUT there are 100x more members there that actually know about these kinds of lasers/ what they are talking about .
Example: http://www.photonlexicon.com/forums/showthread.php/13179-Mega-RGB-via-KTP-Dye-445...-Discuss...

 

[ElektroFreak]

We have an entire gas lasers section here, with lots of good info in it. So does Photonlexicon. The best idea for well-rounded research is to inquire in several places.

For 244nm, you've got several options, both gas and solid state. All the options I'm aware of are manufactured by the most prestigious American or European companies, so I'm fairly sure that you won't be able to find such a laser in that price range unless your application would allow for 266nm instead. Then you can go to an Asian manufacturer like CNI and get a system likely within the price range you specified: http://cnilaser.com/UV_laser266.htm

 

[MrAnders]

Thanks for yout replies. I guess I could use 266, but 244 is prefered. We actually have a 488 laser. So we are also looking into frequency doubling that. It is however not an option to open that laser and place a crystal directly in the cavity.

I found a wavetrain frequency doubler that seems like it could do the job.

WaveTrain CW Frequency Doubler

I written to there sales department but they does not answer. Anybody know what the price of such a unit is, or an alternative solution. That can work for a CW laser. We need some effiency, that is at least 5-10 procent.

 

[ElektroFreak]

That SP doubler would work, but again you're looking at a pretty serious price tag.. Pretty much any time you're talking American manufacturers you're looking at serious money.

Really, though, you could probably mount an LBO crystal or Lithium Niobate crystal on a stage and double that way. As long as you watch your xtal temperature you should be able to maintain good efficiency.

 

[MrAnders]

So you think i just can place a crystal in the beam line?

Any articles or other information on doing that for a CW laser?

That would be nice, such a crystal i fairly cheap.

 

[ElektroFreak]

You can rest assured that a crystal will cost FAR less than an entire system. Alignment will be sensitive, as well as temperature, but yes you should be able to double using only a crystal provided your 488nm source is powerful enough.

As far as information on how exactly to do it, I can't think of any links right now.. it really should be as simple as placing the crystal in the beam path and adjusting it for the output you desire. It never hurts to focus the beam so that the beam waist is in the middle of the crystal, which ensures maximum power density and high efficiency.

 

[MrAnders]

Ok, thanks for your advice. I will ask around, may know some who can help me with my questions on such crystals

 

[HIMNL9]

Uhm, i doubt that just "placing a crystal in the beam" can work ..... those units are tunable and loopback-controlled cavities ..... also coherent, as example, produce something similar, and judging from the principle schematic, it's all, except just a crystal in the beam (and none of the manufacturers post the prices on the net, as far as i know ....)

 

[MrAnders]

yeah didn't think so... :yabbem:. I know the manufactures doesn't post their prices. But maybe someone has an idea of the price range, and if it is more expensive than buying a new 244 nm laser.

 

[ElektroFreak]

Uhm, i doubt that just "placing a crystal in the beam" can work .....

Care to explain why? I think you misunderstand what I said. I was offering an alternative option so that the OP could in theory avoid buying that Spectra Physics doubling monstrosity because it is not necessary if all you want is to double the frequency of a TEM00 laser beam. Amazingly enough, none of my frequency-doubled DPSS heads contain a Spectra-Physics frequency-doubling laboratory device that I know of. .. and yet, somehow the doubling still happens.. and all it takes is the right crystal.

By my logic if you have a stable TEM00 laser beam of a given wavelength and intensity, simply placing a suitable non-linear frequency doubling crystal in the beam path will double it, depending on the orientation and temperature of the crystal of course.. If that wasn't the case, then we couldn't have DPSS pointers, could we? Here's a prime example: http://laserpointerforums.com/f45/do-yourself-complete-green-dpss-o-like-crystals-42495.html. In one of the pics you can see the person holding the doubling crystal in the beam and getting green output. I guarantee that there is nothing more to a green pointer than a laser diode, a crystal that produces 1064nm, and another crystal that frequency-doubles to 532nm. No Spectra-Physics machinery necessary .

Of course the KTP that doubles to green will NOT work in the UV range, but LBO, BiBO, etc. should..

Frequency doubling isn't rocket science. You DO NOT need a ton of extra BS to do it. If you did, we wouldn't have itsy bitsy DPSS lasers, as I said before.

 

[Cyparagon]

That is a little bit different. The vanadate is bonded to the KTP. It might be far more difficult if they were separate.

 

[ElektroFreak]

Actually, if you look closely at mauswiesel's post he's using discrete crystals. Separate Nd:YVO4 and KTP.

It is more difficult if they are separate, you're right.. but not by that much. Look at every single Chinese DPSS 473nm unit around.. just a diode and two crystals. No crazy-awesome frequency-doubling module required. In fact, I'd wager that Spectra-Physics unit is intended to double something like a Mai-Tai or Millennium or some other of their laboratory systems.. It would be even simpler for MrAnders since he's only worried about doubling so there would be only one crystal. Can a whole bunch of cutting edge tech make doubling quite a bit simpler? Absolutely. Can frequency-doubling be accomplished successfully with a heater stage/oven and a single crystal? Again, Absolutely.

 

[LSRFAQ]

I've worked on UV ion. Go over to PL where I check more often and we'll have a PM session. Username over there is mixedgas, and I've actually wrote gratings and holographic optics with etalon and frequency stabilized UV Ion. I've also worked on iodine adsorption locked lasers.

Once over there I'll give you my phone number and we can chat.

I'd do it over here but I am in the middle of helping to handle a few major industry legal problems right now and keeping my friend's business afloat while job hunting. I'm checking Photonlexicon far more often then I can check over here.

Innova FRED, Lexel SHG, and Innova 30X series UV are part of my past cup of tea, as are delta cavity UV schemes. I'm also a former university research associate with three years in a Raman lab and nine years overall. I have decades of experience with ION.

Deep UV on the cheap using external SHG usually requires a level of coherence locking via cavity length control that is art in itself, being diode pumped or ion. However I can't disclose the inexpensive techniques on a open forum for legal reasons.

I may be able to get my hands on a set of conversion optics for a ION cavity for you, as well.

Steve