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ArcticMyst Security by Avery

I got the power....!!!

Trevor

Trevor

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norbyx said:
The LPM is fine, I tested it with all my other lasers and it is just on track. When I did this test I just had my other He-Ne Aerotech on the side, and switching from one laser to the other the readings where right on. The aerotech measured at just around 6mW that was what it should be. Also before it got shipped out the Rigel 6 was measured giving the power readings that where expected. So the LPM is fine.
Now on the shape of the beam, well let me tell you that the dot is quite awful, it is way worse than the Aerotech, I don´t really know if a single mode laser can become a multimode from some bumping around during transportation but it sure doesn´t look like its nice and clean.

Maybe someone can bring some light to this.....
Click to expand...

A laser in TEM00 produces less power than a laser in a higher order mode.

Why?

The higher order mode allows the laser to gain in more of the cavity - so it ultimately outputs more power. So, if the mirrors became slightly misaligned, it could net you a power increase like what you see. Many of the higher powered green lasers coming out of China in recent years owe that power to crazy high-order transverse modes.

Trevor
 





norbyx

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Well I will try to clean the front mirror since to be honest I didn´t try that, the Qtip was there just because I had one laying in the table, but peronally I don´t think it will change much.
On the other hand knowing how a HeNe laser works shouldn´t the power be topped with the mirrors perfectly aligned? I mean I have seen various videos where with HeNe lasers and external mirrors if they are just a tenth of a degree out of alignment they loose power... so how could it gain power from a misalignment?
 
Trevor

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It's not that the laser is misaligned, per se. I'm saying the alignment has changed.

It's a fairly simply concept - if you use more of the gain medium, you will get more laser power. To use more of the gain medium, you have to change the way the laser resonates. To change the way it resonates, you have to change the alignment. You'll get increased power at the cost of beam quality.

With regards to the halo around the beam, cleaning the OC will help, but I would recommend against using Q-tips. They cotton might have abrasive bits in it that could damage the mirror and make the problem worse.

Trevor
 
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norbyx

norbyx

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Well I could try with a microfibre cloth... that should work better. I will try tomorrow if I get to have some spare time, even if it is sunday I still have a ton of stuff to do.
Anyhow I am quite happy with the lasers as they are, they work quite nicely and even if they were kind of expensive to be just red 633, at least they do work fine.
 
Trevor

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Also keep in mind, a gas laser that doesn't run in TEM00 can be beautiful.

Here's my old multiline argon laser at idle:

Q8reVCM.jpg


And at full current, suddenly TEM01:

8TCQExI.jpg


vtMwViy.png


The shorter wavelengths ran in the most beautiful, perfect TEM01 I'd ever seen. I've never seen any other laser like that one. :D

Trevor
 
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norbyx

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Could it have become a multiline laser? That would be interesting.
 
Trevor

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You'd need new mirrors with different coatings for that to happen. I'm pretty sure that didn't happen during shipping. :p

That being said, helium-neon doesn't have a lot of gain on the non-red wavelengths, and can't really run multiline in any sort of interesting way (i.e. red and another color). There are tubes made commercially that produce two IR lines, or a red and IR line.

640nm can lase weakly alongside 632.8nm, but you probably wouldn't notice it. Similarly, occasionally an orange line can show up weakly in a yellow laser. These examples, however, would be due to manufacturing error rather than design.

Your HeNe just exhibits the telltale signs of an altered alignment.

Trevor
 
norbyx

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Well Trevor let me thank you for all the given information. I would rep you if I could but the system just won't let me. I will do as soon as I can...
 
bloompyle

bloompyle

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In the warmup process, if I apply pressure to the mirrors on my REO, it will switch in and out of SL 612 and ML with 594/604/612.

I haven't heard of 640 from anything other than a Raman, given it IS a Raman line.
 
Trevor

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bloompyle said:
In the warmup process, if I apply pressure to the mirrors on my REO, it will switch in and out of SL 612 and ML with 594/604/612.

I haven't heard of 640 from anything other than a Raman, given it IS a Raman line.
Click to expand...

Want to take a video? How stable is the output? How many lines are present at once?

Trevor
 
bloompyle

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I have a thread all about my 2 Multilines. Check my sig :)

I have one stable with 594/604 and another stable with 594/604/612.

They move warmup to multiline in seconds. Just in the beginning, I have to do that for it to lase 3.

Noticed it when I was tinkering with it, I didn't understand the HeNe process just yet, so I was trying to put a perfectly perpendicular mirror on one side to double the output. Silly, yes, but I was new... Anyway, I then tried cleaning the HR and noticed the lines would come and go. So a simple movement of a fraction of a millimeter, can cause spectacular things to happen. It stables out to all 3 lines in a couple minutes max anyway. My REO is my most unique HeNe. People love seeing 3 lasers at once, and orange. :p
 
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daguin

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Trevor said:
Also keep in mind, a gas laser that doesn't run in TEM00 can be beautiful.

Here's my old multiline argon laser at idle:

Q8reVCM.jpg


And at full current, suddenly TEM01:

8TCQExI.jpg


vtMwViy.png


The shorter wavelengths ran in the most beautiful, perfect TEM01 I'd ever seen. I've never seen any other laser like that one. :D

Trevor
Click to expand...

I have a ML argon that gives over 200mW of beautiful TEM10 (looks like a donut)
I also have a high powered Hene in which the output looks like a complex tapestry
Here's a HeNe that is hopping between complex modes



Peace,
dave
 
Trevor

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I remember almost buying that HeNe from you... thanks for chiming in. :D

Also, bloomie, interesting! From everything I'd read on Sam's Laser FAQ it seemed like those couldn't exist... and it turns out you bought those from Dr. Sam himself.

Looks like I need to dive back into the FAQ... :tinfoil:

Trevor
 
bloompyle

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The REO was bought from Dave.

Actually, I have 3 MLs. I forgot to mention the 6 line Raman :rolleyes:

The 612 and 650 lines go nuts when warming up, blitzing through modes like nothing, it'll morph around and sit at a different mode a second before it warms up. Soft seals :rolleyes:
 
n2stuff

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Here's my little green HeNe hopper.

Bloom Can you get all your gassers going at the same time for photo shoot. That would be epic.
 
bloompyle

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That's 2 Argons and 6 HeNe..I'd blow a breaker lol. Plus I only have 3 HeNe psu's. One is designed for the Raman, so the other 2 are just interchangeable. Though I have a 12VDC somewhere..

I will be taking some "rainbow" shots if I can snag another psu. Showing the various greens I have, and the visible HeNe spectrum (minus the Raman).

My current gas related media goal is to get a decent beamshot of 501.7nm. But that's enough thread jacking for me :p

Feel free to post questions in one of my gas threads :) my Raman thread has some pretty sweet new pics ;)
 
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