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My Newest HeNe Toy

daguin

daguin

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In my quest for HeNe goodness, my last one got me 42mW. However, it was a "sealed" housing.

http://laserpointerforums.com/f43/my-best-hene-output-so-far-47450.html

I wanted to see a long plasma exposure. I kept looking. My latest gives me that exposure.

This newest one is a Spectra Physics Model 907. It is ~39 inches overall. I picked it up awhile ago, but my Spectra Physics 255 PSU wasn't quite up to the challenge. It would sputter and flash, but no more. I finally got a PSU that would drive it (LaserWave 390T-5300-11.5). I just got it fired up. It is all still flying leads, but I have light :wave:

IMG_0864.jpg
IMG_0865.jpg


In addition, I need to clean and adjust the optics. it is putting out a whopping 5mW right now. :crackup:

It certainly could be worse. Many of these, (with external mirrors) arrive not lasing at all.

So one more thing to keep me out of the bars at night, eh?

Peace,
dave
 





MarioMaster

MarioMaster

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nice giant HeNe - the tube and magnet setup looks identical to those in my SP-127
 
Hemlock_Mike

Hemlock_Mike

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Dave --

If you move the magnets, can you affect the beam or power ? I've tried exterior magnests on a couple of mine and I don't see much difference.

HMike
 
daguin

daguin

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Hemlock_Mike said:
Dave --

If you move the magnets, can you affect the beam or power ? I've tried exterior magnests on a couple of mine and I don't see much difference.

HMike
Click to expand...

The magnets are all very securely attached and very close to the tube. Before I do anything else, I need to adjust the mirrors. I can significantly increase the output simply by "pushing" on the rear mirror mounts. Even the "spot" is showing a pattern of reflection off of the inside of the plasma channel. This will be much brighter when I finish tuning it up.

Then I may play with the magnets ;)

Peace,
dave
 
roddenberry

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Very neat indeed, Dave. 39" has to be the longest tubes on the market, right?

Beautiful long tubes like that are hard to come by locally and i'd always be afraid to buy one off ebay because of the extreme risk of breakage for such a long tube diring transit. I tried to do a search of the Laserwave PSU you're using and didn't come up with the specs. What power is needed to drive such a long tube?

- Robert
 
daguin

daguin

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roddenberry said:
Very neat indeed, Dave. 39" has to be the longest tubes on the market, right?

Beautiful long tubes like that are hard to come by locally and i'd always be afraid to buy one off ebay because of the extreme risk of breakage for such a long tube diring transit. I tried to do a search of the Laserwave PSU you're using and didn't come up with the specs. What power is needed to drive such a long tube?

- Robert
Click to expand...

For these Laserwave (this one was made for JDSU) bricks, the specs are in the model number:

390T-5300-11.5 = 5300VDC @ 11.5mA

Peace,
dave
 
T

timelablasers

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Hi Dave,
What are the values of the two original resistors on your SP tube? I have the exact same tube with the exact same PS and the tube barely flickered. However when I removed the original resistors and replaced then with a 'guessed' value, it came alive.
I'd like to get the resistor values right so that I don't damage the tube.
Many thanks,
Rob.
 
HIMNL9

HIMNL9

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LOL, this looks identical to the one i have, at least the inside ..... mine don't have a "closed box" container, more like a metal frame ..... it was probably the version made for become mounted inside some machines, as an OEM product .....

I only have the tube, actually, cause the original PSU is gone times ago ..... and yes, those mirrors can be adjusted with the set screws (and they also come unaligned with a lot of easyness :p)

BTW, as far as i remember, the magnets are for polarization purpose, i doubt that they can give you power increments, removing or changing them .....
 
MarioMaster

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The magnets are to reduce gain in the IR lines, as the gain for IR in a HeNe tube is significantly more than that of the 632nm line. Gain on the IR line can become so high in these large tubes that the IR line may become superradiant which means it may lase even without mirrors.

See this section of sam's FAQ - Sam's Laser FAQ - Helium-Neon Lasers
 
daguin

daguin

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timelablasers said:
Hi Dave,
What are the values of the two original resistors on your SP tube? I have the exact same tube with the exact same PS and the tube barely flickered. However when I removed the original resistors and replaced then with a 'guessed' value, it came alive.
I'd like to get the resistor values right so that I don't damage the tube.
Many thanks,
Rob.
Click to expand...

Mine has three @ 27K ohm each (total 81K ohm)

Peace,
dave
 
L

LSRFAQ

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roddenberry said:
Very neat indeed, Dave. 39" has to be the longest tubes on the market, right?

Beautiful long tubes like that are hard to come by locally and i'd always be afraid to buy one off ebay because of the extreme risk of breakage for such a long tube diring transit. I tried to do a search of the Laserwave PSU you're using and didn't come up with the specs. What power is needed to drive such a long tube?

- Robert
Click to expand...

Nope, there is one SP 3x longer, at almost 6 foot, and Spectral in Italy will gladly ship you a new 80 mW.

This is a SP125. I've seen a freshly pumped one with the RF excited boost option as well as the dual DC power supplies do 200mW of 632.8.

I don't suggest buying them unless you see them running, and the resonator is a SOLID invar rod the size of Manhatten. Bring a truck, a extra set of hands to help lift it, and a huge shipping crate if you find one, but personally pick it up, NEVER put a 125 in a commercial shipper's hands.. They haven't been made since the mid 1980s, although a few have been professionally repumped. They were rated 50 mW single mode, approached or exceeded 100 mW multimode, and more then that when repumped. There are IR ones out there, so don't be shocked if yours does 1.5 micron IR instead of red.

auction site:

http://www.recycledgoods.com/produc...HeNe-Laser-tube-with-325-Cavity-Extender.html


Steve
 
Last edited:
L

LSRFAQ

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MarioMaster said:
The magnets are to reduce gain in the IR lines, as the gain for IR in a HeNe tube is significantly more than that of the 632nm line. Gain on the IR line can become so high in these large tubes that the IR line may become superradiant which means it may lase even without mirrors.

See this section of sam's FAQ - Sam's Laser FAQ - Helium-Neon Lasers
Click to expand...

632.8 and 3.39 microns share the same upper state,, 3.39 will thus depopulate the 632.8 population inversion if the Zeeman split is not there to reduce 3.39u gain.

3.39 will lase off the reflection off your fingernail, so killing it is important.

Adding more magnet usually reduces the power, as you start to zeeman split the red lines, instead of the IR.

Steve
 
daguin

daguin

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LSRFAQ said:
Nope, there is one SP 3x longer, and Spectral in Italy will gladly ship you a new 80 mW.
This is a SP125. I've seen a fresh;y pumped one with the RF excited boost option as well as the dual DC power supplies do 200mW of 632.8.
I don't suggest buying them unless you see them running, and the resonator is a SOLID invar rod the size of Manhatten. Bring a truck, a extra set of hands to help lift it, and a huge shipping crate if you find one, but personally pick it up, NEVER put a 125 in a commercial shipper's hands.. They haven't been made since the mid 1980s, although a few have been professionally repumped. They were rated 50 mW single mode, approached or exceeded 100 mW multimode, and more then that when repumped. There are IR ones out there, so don't be shocked if yours does 1.5 micron IR instead of red.
auction site:
Spectra Physics 125 125A 50 MW HeNe Laser tube with 325 Cavity Extender - RecycledGoods.com
Steve
Click to expand...

My 42mW feels so inadequate now :yabbem:

j/k :evil:

Peace,
dave
 
HIMNL9

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50 MW ? ..... LOL ..... :na:


daguin said:
My 42mW feels so inadequate now :yabbem:
j/k :evil:
Peace,
dave
Click to expand...

:eg: Well, i can give you mine, so you can couple them in serie and ..... no, wait, what the hell i'm saying ? ..... nevermind :p :D

(but, just for the hypothesis ..... who know if two of these tubes can be coupled in an U-shaped resonator ? ..... the alignment can be a nightmare, if not for other :p)
 
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