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

Look what came in the mail toady.:wave:

It's a 10mW 473nm labby and my first 473nm laser. I must say that I am pretty impressed with the build quality. Everything looks very well made.

It is regulated to operate at 10mW by a photodiode/pickoff-lens mounted on the front of the laser. However there are ways of getting more power out of it. If you remove the pickoff lens the output becomes noticeably brighter but is also more unstable because the power supply no longer has that feedback to regulate the current. But it does stabilize after a while. In either case the powersupply and driver do get warm but not hot, probably about 90-100 degrees or so. The laser head on the other hand stays quite cool. Even when running with the pickoff lens removed, and the output being close to 30mW, the head still barely gets warm.

After about 30 second or so the beam intensity is rock steady, partly because of that photodiode regulation, and the green stabilization LED turns off. The beam diameter at aperture is VERY small, about 1mm. However the divergence isn't so great and there is a bit of splash around the dot. At 8ft the dot is about the size of a quarter. It's probably in the ~7mRad range. But it does run at TEM00. I haven't seen any mode hopping, ever actually. None of the DPSS lasers I've ever owned have ever mode hopped.

Running the laser without the photodiode is not recommended. But there is a small potentiometer on the board that Dr. Lava and others on PL confirmed control the diode current. I gave it a full turn clockwise and the power jumped up a few mW, but it did take a little longer for the stabilization LED to turn off and the driver ran a bit warmer. In any event it's not a very powerful laser but that doesn't mean it's not bright. I complete darkness I can see the beam quite clearly without any smoke or fog. Compared to 445nm it looks turquoise, and 445nm looks even more violet like.

All things considered, it's a very nice 473nm laser for only about 100 bucks. I'm a wavelength junkie so I had to have it, and 473nm is my new favorite color.

473 nm Blue Laser, DPSS, B&W Tek BWB-10-OEM - eBay (item 220627562628 end time Aug-23-10 16:48:21 PDT)





Apparently it's max power is 10 watts.



You can see the purple glow of the IR, that's how the camera picks up IR light.


The camera picks up the splash a bit brighter than it actually it. It's really not that bad.




This is the pot that controls the diode current.


-Tony

I bet the seller hates 445nm, he's got a bunch of them now and nothing to do with them. And I believe the build quality is so great because CNI made the head, B&W just rebranded them. Nice review though. On the pickoff assembly, is it dusty or is that just because of the camera?

B&W Tek also made the driver I believe, they just contracted CNI to produce the actual laser head.

They are great units for wavelength collectors

I've been helping them out - the last two aren't lit because my power strip only had six plugs
Click Image to Enlarge

Since you've only got six slots on your power strip I'll just take those last two off your hands. :san:

MarioMaster said:

B&W Tek also made the driver I believe, they just contracted CNI to produce the actual laser head.

They are great units for wavelength collectors

I've been helping them out - the last two aren't lit because my power strip only had six plugs
Click Image to Enlarge

Click to expand...

What diabolical project do you need eight 473nm lasers for?!

-Trevor

I messed with it a little more today and was ablt to fix the divergence down to about 1.5-2mRad! At 50ft the dot is about the size of a quarter now. That's much better than I expected.

I used the optics from a dead green laser I had lying around. There were two lenses that I had to add to get the divergence down. The cool part is that I was able to mount them both inside the module itself. You'd never know I messed with the beam unless you take it apart.

The fist lens I mounted as close as I could to the pump diode itself. I didn't want to use epoxy for two reasons. First it takes too ling to dry and unless the lens was mounted perfectly, the first time, it would have been a pain in the ass to have to remove it, re-gule it and let it dry again. Secondly, the lens really doesn't need to be cemented in place so I just used hot glue. It's not pretty, but it works.

For the second lens I machined off the brass holder on the green module and that will allow me to adjust the dept of the second lens to adjust the focus. There is space after the IR filter but before the photo diode to fit the mount for the second lens. So the IR filter is between the two lenses.

Oh by the way, DO NOT MESS WITH THE DIODE!!!!!!!! I, unknowingly, unscrewed the diode mount and miss aligned the diode relative to the optics. It wont lase unless the diode is in just the right spot, or if it does lase it'll lase at TEM-WTF!!! You've got like 1/2 a mm of tolerance to get it in the right spot. It took me the better part of an hour to get the damn thing to lase again.

Finally after much fine tuning and adjustment it's lasing again and with a nice tight beam. I probably lost a few mW form the lenses, but it's a small price to pay for a better beam. It's got great divergence now.

These are the lenses from the green laser:


The KPT for the green laser is right under this lens:


The second lens conveniently has threads:


I cut off the mount from the old module to hold the optic.



Here is the first lens mounted right nest to the diode, which is inside that pale plastic housing.


The front assembly bolts on nicely even with that brass holder glued in there.


Here is the dot at over 50ft, whereas before it would have been like 2ft in diameter.



-Tony

Nice modification, messy dot though, is that the lens, or is it dirty?

Glad to hear it worked

Also, you're mounting the first lens to the crystal assembly not the pump diode

brando132 said:

Nice modification, messy dot though, is that the lens, or is it dirty?

Click to expand...

Yeah I cleaned them as best I could but they were still a bit scratched. But it's not as bad as it looks. The camera picks up the splash a little brighter than it actually is.

MarioMaster said:

Also, you're mounting the first lens to the crystal assembly not the pump diode

Click to expand...

You sure, is that not the diode mounted on the TEC?



-Tony

It's a little harder to see the diode since the chip is covered by a metal cover to protect it.

Diode -> lens -> anamorphic prisms -> lens -> crystal cavity -> output

wire end -> aperture end

I'm for sure gonna buy it sooner or later, but still, shipping cost is over half-laser price, I'm just gonna mess around with it (like try to install a 2W+ 808nm laser diode) because 10mW is not enough for me, but yet, worth to play around for that money.

btw. I'm pretty sure there is a ND:YAG? (or maybe ND:YVO4?) crystal coated for 808nm->946nm and BBO (BiBO) or LBO (not sure) to double frequency, can anyone confirm that?

.3lite said:

I'm for sure gonna buy it sooner or later, but still, shipping cost is over half-laser price, I'm just gonna mess around with it (like try to install a 2W+ 808nm laser diode) because 10mW is not enough for me, but yet, worth to play around for that money.

btw. I'm pretty sure there is a ND:YAG? (or maybe ND:YVO4?) crystal coated for 808nm->946nm and BBO (BiBO) or LBO (not sure) to double frequency, can anyone confirm that?

Click to expand...

I have one that's outputting slightly messy (TEM00 + an extra dot from TEM01) that I'd sell you at a discount, if you're interested.

-Trevor

.3lite said:

I'm for sure gonna buy it sooner or later, but still, shipping cost is over half-laser price, I'm just gonna mess around with it (like try to install a 2W+ 808nm laser diode) because 10mW is not enough for me, but yet, worth to play around for that money.

btw. I'm pretty sure there is a ND:YAG? (or maybe ND:YVO4?) crystal coated for 808nm->946nm and BBO (BiBO) or LBO (not sure) to double frequency, can anyone confirm that?

Click to expand...

Im not sure what frequency doubling crystal it uses, but it already has a 2W+ diode in it. The crystal efficiency is low.

Most of mine do >20mW with the feedback sensor removed.

Thanks for posting this Tony, very informative!

473s usually use LBO as the doubler crystal.

I removed the photo-diode on mine just to play with it a bit, and I noticed that the dot did become a bit brighter. I also took notice when it stung the back of my hand. It will barely smoke electrical tape as well. That's got to be a bit more than 20mw.. perhaps 25-30?

Tony, once I removed the sensor on mine, I heard a tiny little 'sizzle' coming from the head. It's very quiet, but it sounds a bit like white noise. Do you have the same going on with yours?

EDIT: Also just noticed that the entire driver heatsink is running at about 55 degrees centigrade. It kind of caught me off guard.

Meatball said:

I removed the photo-diode on mine just to play with it a bit, and I noticed that the dot did become a bit brighter. I also took notice when it stung the back of my hand. It will barely smoke electrical tape as well. That's got to be a bit more than 20mw.. perhaps 25-30?

Click to expand...

I'm thinking 30mW without the APC. The power density at the aperture is nuts.

-Trevor

Well I did say greater than 20mW, mine usually average 30 with peaks around 35mW as the crystals stabilize.