B&W Tek BWB-10-OEM - 473nm 10mW

[ZRaffleticket]

Gotta love the first time you see 473nm. Favorite laser color! Hopefully you get that weird dot shape cleaned up. that reminds me to clean my own lens... I think there's a hair or something on it.

 

[Things]

Yep, has to be my next favourite colour beside multiline argon! It's such a pure blue. My ML argon is actually a fair bit more on the green side, it has a very strong 515nm line, but I haven't been able to get it started for a comparison shot yet.

Put it next to my projector and projected a 445 beam, definitely makes it look like 405!

 

[n2stuff]

Yep the 473 is a awesome color. Such a nice almost powder blue. That a nice shot next to a 455 and you are right about the 455 looking like a 405. I still need to get a multi line argon. Those are bad ass gas

 

[vk2fro]

LOL at bad ass gas - if you have this problem, you need to change your diet

Nice comparison between 473 and 445 there Things. That projector box looks familiar

 

[Hiemal]

I got one of these a while ago, and also purchased a 500 mW 808 nm diode from Laser Direct on Ebay... I wanted to make a small handheld from one of these.

I understand "no off spec diodes" from ebay. Originally Laser direct had sent me a 805 nm diode, as each diode seems to have a separate spec sheet, which is nice. I spoke to him about what I planned on using it for, and he let me exchange the diode for an 808 nm on the DOT diode free of charge.

However, it seems regardless of how I align the diode or focus it I can't get any light at all out of the 473 nm assembly... Green sets pump perfectly fine, but the 473 I can't get jack squat.

Is there something I'm not doing correctly that maybe someone could give me pointers on?

Thanks.

 

[Hiemal]

No one have any ideas what to do? I already tried PMing JLSE about it, but he's either busy or doesn't seem to want to help.

If it's anywhere as easy as JLSE makes it out to be then I don't understand why I'm not getting any light.

 

[ElektroFreak]

First, do you have any internal pics of your setup?

Second, blue DPSS is notoriously hard to do because the doubling crystals are very temp. sensitive. The efficiency curve is very steep, with a peak across a very small band of temperatures. Outside this small temp. range there will be little to no blue light generation. This might be part of the problem, since in a handheld you're not likely to be using TECs for stabilization. Another possibility is that there is still an alignment issue somewhere. The parameters for the diode, it's position, the alignment and temperature of the crystals etc. are all much more stringent than with green DPSS.

 

[Things]

So, got my M9x0.5 tap today, and after a bit of messing around making sure I was tapping and drilling straight etc, I ended up with this:

This is the little expander lens that's found right after the crystal assembly in some random green pointer. Hot glue isn't the best, but it works fine, and is relatively easy to break off if you get it wrong:

And the dot:

Bit of splash, but for the price, these are definitely great lasers! 473nm ain't getting any cheaper than this, so if you haven't seen it yet, get one to check out

 

[Jmillerdoc]

Has anyone ever pulled the crystal set out of one of these and tried to use a different method of injecting the 808nm into it? I've got several 1w 808nm 9mm diodes and one of these (actually have two, one works) heads I killed. I was thinking of putting a 808nm 9mm diode into a 12mm lens assembly and attempt to focus the output into the LBO unit to see if it would work. Anyone with any attempts at something like this? Any thoughts, warnings (other than the obvious proper eye protection), suggestions? I can't stand the fact I've got a perfectly good LBO crystal set rotting away without use. If this could be done it should be pretty easy to put it into some sort of hand held device for short run times. If the TEC on the LBO could be powered as well then even longer times should be attainable. It appears that with all of the critical optics between the pump diode and the LBO it must require some precision alignment, unlike the KTP crystals I've bombarded with 808 and got a nice fine green beam from. Anyone know why alignment of the 808 into the LBO is so critical compared to the KTP?

Thanks for the thread, this has been great reading!

 

[Sigurthr]

IIRC it has to do with needing a certain axis of polarization relative to the crystal set. I've realigned these heads before successfully several times before selling mine off, it isn't all that difficult, but that's with the anamorphic prisms in the head. Trying to bypass them... no idea.

 

[ultimatekaiser]

With an LBO, the rules change a bit. They have a lower coefficient than a KTP, thus requiring a more precise angle, and are very temp. sensitive, and moisture sensitive. But there should be two crystals, the yag needs to be pumped for your 946 first, which has a much lower gain than 1064. Also, you should use a c-mount for DPSS. TO-CAN packages don't work very well. You have to stabilize the pump to exactly 808nm or you'll rapidly lose lasing. After, focus all of the 808 down to a stable profile straight into the yag. You'll need to know the polarization of the crystals and diode and match the yag polarization to the diode's (and make sure the crystal isn't backwards). Once it's enough to meet threshold you'll get your 946, then feed this into the LBO. If everything is straight and on axis-you should have a beam to work with, (again assuming polarization and orientation are correct) reality will probably be different. this is assuming the crystals are doubling as the mirrors, which isn't always the case...then the mirrors have to be lined up as well, and the LBO and diode get hot fast, which also causes issues.

There's a lot of other factors too in short 473 is a lot harder to get. Not like 532 where you can just can feed it light and get something else using those hybrid 2-in1 crystals often used in green processes. This is one that requires a bit more know-how, a lot of patience, a steady hand, and some luck.

 

[Jmillerdoc]

Seems to me having a single mode 898nm diode would be very helpful here. Would eliminate the need for all the prisms and such you would think. I was quite surprised to see two lenses separated by a pair of prisms BEFORE the crystal set, with your explaination Mr. kaiser I see the light (pun intended).

Would you agree that a single mode 808 would make this process much easier? Or am I making too many assumptions in what you just said?

 

[ultimatekaiser]

You are right. Single mode c mounts are best generally. FAC makes it even better. Cooling is better, and you can get optics closer to the diode die if needed.