Best NLO Crsytal for Doubling 980nm

So if i were to buy a high power 980nm laser diode, what crystal would be best to double the frequency to 490nm? What would i see in terms of efficiency?

I saw a 5W C-mount laser diode at 980nm, and was thinking that if i got 5W out of it, i would be able to get at least 50mW of 490nm with the right doubling crystal with only 1 pass through it. i think phase matching might be a problem too, though.

It's very, very, VERY hard to do direct diode doubling. You need a very high power density to achieve doubling, and this is practically impossible to do with multimode lasers. It's much easier to stick to single mode ones, if you don't want to mess with a ton of optical correction. And even then, the temperatures need to be almost perfect. If you are still committed enough to try, I would use LBO or BBO, both can achieve good efficiencies under 500nm, unlike KTP. Good luck!

micheal rosen said:

So if i were to buy a high power 980nm laser diode, what crystal would be best to double the frequency to 490nm? What would i see in terms of efficiency?

I saw a 5W C-mount laser diode at 980nm, and was thinking that if i got 5W out of it, i would be able to get at least 50mW of 490nm with the right doubling crystal with only 1 pass through it. i think phase matching might be a problem too, though.

Click to expand...

I don't think 490nm can be done the way you imagine---not commonly or easily or at reasonable cost. Classical wavelengths of frequency doubling solid state lasers are 473nm, 456nm, 457nm, ans 458nm.

CNI does offer 1 to 2mW 491nm DPSS labby but nothing more powerful.

"a continuous-wave (CW) blue laser emission by sum-frequency mixing in Nd:GdVO4 and Nd:YLF crystals. Using type-I critical phase-matching (CPM) LBO crystal, a blue laser at 490 nm is obtained by 1063 and 908 nm intracavity sum-frequency mixing. The maximum laser output power of 118 mW is obtained when an incident pump laser of 18.2 W is used. At the output power level of 118 mW, the output stability is better than 4.2%" From: 490-nm generation by sum-frequency mixing of diode pumped Nd:GdVO4-Nd:YLF lasers - Springer

If you search for 490nm laser on sams laser faq you will see how a commercial direct doubled laser is made...it is NOT as simple as a diode and a coated crystal.

go to toptica website, they stock 488nm-505nm ranges...but expect the diodes to cost $,$$$....

Try getting yourself in contact with the member lazereer (angelos). If anyone can give you tips, it'd be him.

And no, it's not going to be impossible, though it'll be one hell of a sharp learning curve. Try playing with 532nm if you're serious about it--

doubleone44 said:

It's very, very, VERY hard to do direct diode doubling. You need a very high power density to achieve doubling, and this is practically impossible to do with multimode lasers. It's much easier to stick to single mode ones, if you don't want to mess with a ton of optical correction. And even then, the temperatures need to be almost perfect. If you are still committed enough to try, I would use LBO or BBO, both can achieve good efficiencies under 500nm, unlike KTP. Good luck!

Click to expand...

well, the diode i found has fast axis correction, so that paired with its extremely high output would probably help. i understand that this will not be easy, but i figure i could do it for under $500.

micheal rosen said:

well, the diode i found has fast axis correction, so that paired with its extremely high output would probably help. i understand that this will not be easy, but i figure i could do it for under $500.

Click to expand...

You better have a chat with whomever you are going to buy crystals from --they will know better what can possibly work and costs associated with same before you waste a lot of time and money---this stuff is well known--no need to guess/experiment/reinvent the wheel.

see: Advanced NLO Crystals for Efficient Blue Laser Sources Based on SHG Processes " La(Ca1-xSrx)4O(BO3)3 - LaSrCOB crystals (x = 0.0, 0.1, 0.3, 0.4) of good optical quality were grown by the Czochralski method and characterized. By a proper choice of the compositional parameter x, we can obtain blue light in the range of 495 - 473 nm through type-I NCPM SHG in LaSrCOB crystals."
https://www.osapublishing.org/abstract.cfm?uri=ASSL-2015-ATu2A.3

Also have a look at: Second-harmonic generation(how to get from a wavelength of 980 to 490 nm)
"The goal of this experiment in nonlinear optics is to study the conversion ofa (very small) fraction of laser light from its original wavelength of 980 nm (i.e.invisible to the naked eye) to its second-harmonic at a wavelength of 490 nm.Thisconversion takes place by mild focussing of an intense laser beam in a nonlinearbirefringent crystal of BBO (= ¯ BaBO4)."
http://users.uj.edu.pl/~ufdzierz/PracFot/SHG_Dood.pdf

"Some companies make blue lasers by direct doubling a 980 nm diode. But this is not easy, because you need a very good beam quality which requires a single mode diode - not available at high power. The other problem is that you have to use extra-cavity doubling (since you can't get inside normal diodes!). With cheap multimode diodes, there is no way to do the needed beam shaping. You can build a nice green laser using 980 nm diodes and Yb:KGW (1,025 to 1,045 nm; greater than 50% efficiency) and doubling with KTP. KGW has its major absorption wavelength at 980 nm - the problem is that it is not cheap (starts from $1,000/crystal)." From Sam's Sam's Laser FAQ - Solid State Lasers

Nevermind guys, i found a company that makes waveguides for lasers that are made of frequency doubling material. i would literally just need to shine the laser diode into it from close up, and it would guide the light along it and turn it into cyan. were looking at 5% at best here, and that's pretty damn good!

micheal rosen said:

Nevermind guys, i found a company that makes waveguides for lasers that are made of frequency doubling material. i would literally just need to shine the laser diode into it from close up, and it would guide the light along it and turn it into cyan. were looking at 5% at best here, and that's pretty damn good!

Click to expand...

Link? Price?

Also, I suggest giving this thread a look: Why can't we frequency double 1208nm ?

H2Oxide said:

Link? Price?

Also, I suggest giving this thread a look: Why can't we frequency double 1208nm ?

Click to expand...

No prices yet, but heres the website: Covesion Ltd. - PPLN, MgOPLN, Mid-IR OPO, Green SHG


the crystals require precise heating, and ill need to buy the crystal in an oven with a controller from them, so this project is NOT going to be cheap. ill be discussing with a representative about the options, ill keep you guys updated.

micheal rosen said:

No prices yet, but heres the website: Covesion Ltd. - PPLN, MgOPLN, Mid-IR OPO, Green SHG


the crystals require precise heating, and ill need to buy the crystal in an oven with a controller from them, so this project is NOT going to be cheap. ill be discussing with a representative about the options, ill keep you guys updated.

Click to expand...

Be prepared for a 4 figure + quote, waveguides are expensive as hell AFAIK.

If you do decide to go through with it you should look at Wavelength Electronics for TEC controllers. The TEC itself shouldn't be too much.