Yellow HeNe Laser Tube for Sale

[Fullhouse Productions]

Hey laser team,

I've got a NOS Yellow HeNe for sale on ebay. The output is 2.52 mW. I know these are hard to find so I thought I would let yall know. The auction ends on Sunday.

Thanks,
Matt

[Jem]

Do you have a link? Is this eBay USA?, Australia?, Europe?, Outer Mongolia?, a swamp somewhere in Africa?

How about filling in you location in your profile?, that would be a start

[142laser]

From the model numbver it is 0.50 mW minimum spec multimode buit could output 2.5 mW if NOS I suppose. Random polarization, not 100% TEM 00.

[pschlosser]

Here ya go: Yellow HeNe Laser Chorus | eBay

[The_Doctor]

From the model numbver it is 0.50 mW minimum spec multimode buit could output 2.5 mW if NOS I suppose. Random polarization, not 100% TEM 00.

Why would random polarisation prevent TEM00? I thought the spatial mode could be TEM00 independent of polarisation, which could be random, planed, or circular depending on other optics that may or may not influence the mode in ways not directly related to their effect on polarisation. And did I just spawn yet another huge multipage HeNe discussion?

[Fullhouse Productions]

Hey laser team,

I've got a NOS Yellow HeNe for sale on ebay. The output is 2.52 mW. I know these are hard to find so I thought I would let yall know. The auction ends on Sunday.

Thanks,
Matt

LOL, sorry about that Jim. I could not remember if I could provide a link without violating site policy. He's the link http://www.ebay.com/itm/181250095112...84.m1555.l2649

[SoulFeast]

Why would random polarisation prevent TEM00? I thought the spatial mode could be TEM00 independent of polarisation, which could be random, planed, or circular depending on other optics that may or may not influence the mode in ways not directly related to their effect on polarisation. And did I just spawn yet another huge multipage HeNe discussion?

The random polarization is not what makes it not TEM00.

The M = multimode
The R = random polarization

Multimode could be the attempt to get high output from a small tube by widening the bore. There is more light that is now active. Basically, when it is very narrow, the light needs to be 100% perpendicular on itself to resonate well. With a wider bore, it can be 99.9999% for instance, which causes the beam to not collide dead on with itself, but perhaps slightly askew. So now the beam isn't a single TEM mode, but multiple.

Imagine the tube, not imagine the bore inside, a very narrow tube. In this tube, the light should for all intents and purposes, resonate parallel on itself, perpendicular to the mirrors on each end. More-or-less. With a wider bore you have more light now occupying this space, meaning more places on the mirrors for light to reflect off of. Now light has the chance to hit the edges of the mirror. These mirrors are generally concaved, so if light hits it dead center, it will reflect on tiself, and narrow the beam. Similar to focusing a laser beam, but reflecting rather than passing through.

When light has the ability to hit slightly off of center, it now bounces erratically. Hitting the edge of the bore, and it's no longer perfect. Some of this light that's just a fraction off, still has the ability to fold and gain on itself. Meaning you now have resonation still, but it's not in the perfect slim form of TEM00.

Could explain why it is doing 2.5mW, but just multimode. Though it doesn't explain why it is rated for a fifth of that...

Gas is fun

[Fullhouse Productions]

Just took care of the profile thing. Thx again for the heads up.

[The_Doctor]

The random polarization is not what makes it not TEM00.

But you're telling him that, and not me, right? I was highlighting the error or ambiguity by questioning it, I didn't make it. I knew about the reflections and the wider bore and multimode thing (I had three mulitmode HeNe's at one point). And as far as I know, you won't get plane polarisation unless you put a Brewster window in the cavity, a thing that won't of itself cause a modal change.

I questioned the original statement because it seemed odd coming from a guy who is apparently working with Sam. If there is ambiguity or error coming from the top down it makes no sense to make it look like it came from the bottom up.

[SoulFeast]

I am pretty sure he was just listing its properties, not implying that the two were related.