Trying to build an insane 532 nm laser

[lasersbee]

With growing excitement I read just now the OP and the first page of this NOW de-railed thread.. then.. pages 2 and 3 --wasted space.
STOP!!

no more posting!! even agreeing, saying sorry or thanking posts -- you can do that by +repping .



@ the mods..
its known you have been trying but..
more needs to be done about this-- it is NOT getting better...
we can do it if you like...

I sure would like to see this thread continue (and the deletion pages 2 & 3)

or we can do THAT as well.. if ALL (others)deleted their posts on those pages--
that would be effective.


reason for deletion: I refused to be a part of re-railing a great thread.

You're a little late to the party Hak...:beer:
It was already solved on Aug 21/17...

http://laserpointerforums.com/f59/ban-information-thread-74624-8.html#post1492068

Jerry

 

[hakzaw1]

oops.
did I do that??

 

[Laserbuilder]

BTW, I've found a shard from a big He-Ne tube with a big Brewster window. Will it work as a polarizer if I put it into the resonator of the YAG laser? How can I make sure then that the laser beam is polarized?

 

[diachi]

BTW, I've found a shard from a big He-Ne tube with a big Brewster window. Will it work as a polarizer if I put it into the resonator of the YAG laser? How can I make sure then that the laser beam is polarized?

Brewster angle is wavelength dependent, it may be close enough to work though, I'd build in some adjustment if you can.

To determine polarization just use a PBS or some other polarization dependent optic to see if the beam is blocked/reflected at specific orientations.

 

[paul1598419]

The Brewster's angle is wavelength dependent and there is quite a lot of distance between 632.8nm and 1064nm or 532nm. Aren't those angles set in the HeNe shard? I don't see a way forward with it, but I have been wrong before.

 

[diachi]

The Brewster's angle is wavelength dependent and there is quite a lot of distance between 632.8nm and 1064nm or 532nm. Aren't those angles set in the HeNe shard? I don't see a way forward with it, but I have been wrong before.

There's a little deviation allowed, best bet would be to mount the plate/stem so that it's adjustable over a couple degrees.

That or buy a Brewster plate specifically cut/mounted for 1064nm.

 

[CurtisOliver]

Even though this is a old thread now. Laserbuilder, the very best of luck with this. Look forward to seeing your results. Some good help mentioned already.

From what I've found, things to take into account:

• polarisation (very important)
• phase matching (also important unless NCPM)
• power density (depends on damage threshold of crystal)
• temperature (some crystals are more efficient at certain temps)
• hygroscopicity (LBO etc)
• coatings (ar and hr)

It is such a shame KTP can't be used on high power systems. Well, not without sacrificing on a larger beam diameter anyway.

 

[Laserbuilder]

Thanks for your replies.
AFAIK, Brewster windows of He-Ne tubes are made of fused quartz. And yes, the Brewster angle is wavelength-sensitive because the refractiotion coefficient is different on different wavelengthes. But as for quartz -- it has n=1.53 at lambda=1.2 um and n=1.54 at lambda 0.67 um. So, the difference is miserable. I hope it will work.

 

[ultimatekaiser]

yes, the difference is there, but super negligable. all you need is an optical flat that passes said wavelength, and just turn it until it's at the appropriate angle. fused quartz is usually the standard material for most visible and NIR sources. often times they just cut one end of the rod at the appropriate angle and build a ring out of it if they want to control the frequency and polarization, as it requires fewer optics and runs less risk of damaging them from thermal load and other issues.

 

[paul1598419]

Quartz is birefringent, if I'm not mistaken.

 

[diachi]

Quartz is birefringent, if I'm not mistaken.

It is.

It's well suited for Brewster plates though, very wide wavelength range. 185nm to 2100nm. Plenty of other good properties too.

 

[lazeristasUVISIR]

Laserbuilder, what is your experimental setup right now? (this thread as I see was started half year ago)

As I remember a Brewster plate is not coated - it's just a not too thin not too thick glass or fused silica plate orientated at a Brewster angle. Though don't know for lasers with double wavelengths like 532 and 1064. It was a long long time ago when I repaired a 1064/532 laser - it had a plate but don't recall if it was coated and what kind of alignment was needed.

 

[Laserbuilder]

Laserbuilder, what is your experimental setup right now?

At the moment it is disassembled and put into storage. I'm trying to get running a big argon laser but have trouble with the power supply. After that I hope I will return to this project, possibly I'll re-assemble it customly on a thick aluminium plate instead of modifying those LTI-501 lasers.

 

[CurtisOliver]

Best of luck. That's the problem with laser projects. Often you end up with more than one on the go.

 

[Laserbuilder]

I think I will return to this project soon, as I've made the GOS1001 laser working. I've drawn a rough optical layout of the green laser. It will utilise 2 130W pumping chambers an a big lithium niobate crystal. Will this layout work? And where can I get a curved HR mirror for 45deg reflection?

 

[Laserbuilder]

Ok, I'm back after a long time of absence, as I've been working on this project, and, finally, got something. The green laser that I have now is not "insane" yet, but I find it worth showing here, as it already beats the majority of laser pointers and small chinese lab DPSS modules. I am continuing to modify the LTI-501 laser head. I had to cmpletely rebuild the main power unit for the lamp, make a fully custom AO Q-switch controller, rebuild the water chiller, make a light detector for controlling the shape of light pulse of the laser, find a completely new pumping chamber for the laser head, tweak the optics and find a suitable frequency doubling crystal. The full story will take a couple of messages, but here is a small teaser.

PS: If you want a high power green laser -- the best way is to buy a Laserscope KTP532 or a copper vapour one. That will save loads of time and effort. It is a severe pain to DIY a frequency doubled laser.