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FrozenGate by Avery

473 nm and moving crystals...

Hiemal

Hiemal

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Hey all, I was contemplating taking the crystals out of one of those defunct 473 nm lab lasers everyone's getting, and remounting them in a (former) green pointer...

Would it be terribly hard to get it all realigned? I've played around with DPSS systems a little bit and managed to get green light out well enough. I'm just worried because the crystals from the 473 nm are not monolithic...and therefore it might be a little bit difficult getting them BOTH aligned.

It would certainly be cheaper than buying a 473 nm handheld for sure.
 





It will be very difficult to do so in short. Sure, it's possible but improbable. If you can get the optics cheap enough it's worth a try though.
 
If it is from the BW Tek units it will not fit in a pointer or standard portable flashlight type host. The diode is C mount and on a large TEC block, there are anamorphic prisms in mount assemblies, intracavity focusing lenses, and finally the nonlinear section is fairly large and on it's own special TEC regulating block. Aligning everything in the housing it comes with is a bitch because there is no spare room. I can't imagine trying to fit one in a portable form factor, much less trying to get all the TEC temperature regulation to work, and then there is alignment...

Oh, also the crystals are hygroscopic and need to be in an air-tight environment.
 
Short answer: nope, not happening.


Long answer:

There's several factors that come into play, and the crystals not being monolithic is the least of your concerns.

1. Form Factor -- you're going to need a big host if you want to fit the assembly into it. You're also going to need to get the TEC and heater assembly for the LBO into the handheld, as well as its control module.

2. The crystals are moisture sensitive -- the moment you crack open the seal on the white optics block, the moment the crystals start degrading. LBO is extremely sensitive to moisture, and unless you've got an ultra-low-humidity workspace, it's best not to open the thing up.

3. Pump power and stability -- Nd:YAG is extremely sensitive to fluctuations in pump wavelength. It likes exactly 808nm and exactly 808nm only. Even variations of 0.3nm in the pump wavelength will produce drastic output fluctuations.

With Nd:YVO4, it's a non-issue, and that's why greens are a lot less picky about the quality of the pump diodes.

4. Phase-matching -- this goes back to the point about the pump diode -- the pump diode needs to be precisely phase-matched to the crystal assembly. Otherwise, you'll get no output.

There's two types of blue out there at the moment: one that requires little phase-matching (and precise temperature regulation), and another that requires precise phase-matching (but little temperature regulation).

The lab units use a crystal assembly with the former assembly (because there's room for a crystal assembly TEC and a separate diode TEC), while handhelds use the latter.
 
I have disassembled 473nm laser and tried later to align crystals again - couldn't get a single photon of 473nm anymore, assembling and aligning crystals for 532 is nothing compared to this one :P

I haven't given up hope yet, out of time though.
 
Oceansoul said:
It'd have been a lot more difficult if you had to unzip the entire sled on which the doubler and YAG were mounted.

Nonetheless, nice work. :)
Click to expand...

I had already done this on the entire optical train from the donor labby
as well as 25 or so others... I picked a bunch of dead units to get some
hands on learning time in on 473's.

The output of the head used when purchased was 10mW IIRC, with the
same pump and parts, I had this one hitting 80mW after warmup from 1W
of 808.

Mind you the optics in the original labby were far more intricate, I will now be
pumping the same crystal set with 3W at completion of this project.. I hope
the extra power will up the output accordingly. :D
 
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