What can I do with a 5mW industrial Ne-He laser?

[Bratan]

I recently got a $5 laser at a garage sale. When I saw size of it and heard that it was "industrial" I instantly imagined cutting metals, etc. :drool: Only after I brought it home I realized that it's just 5mW. It'a a Siemens (made in Germany) and has power supply with a key and works perfectly as far as I can tell. It's class IIIb (but I think that's old standard). Is it any more powerful than a $3 keychain laser with same 5mW rating? Can it's power be increased or is it pretty much worthless piece of antique tech?

 

[aryntha]

It is *brighter* than a $3 keychain laser, as its 632.8nm (more of an orangish red) vs the keychain laser's 660-670nm deep red. So not neccessarily more powerful (though granted, most "5mW" keychain lasers are actually 2-3mW, whereas this is likely actually 5mW).

It will appear ~3-4x brighter at the exact same output.

You can do holography with it, if you're into that sort of thing. You can't increase its output, unfortunately. It's output is based on the size and length of the physical bore.

And if you don't find it interesting, I'll buy it from you for $15 and you'll make a profit I like gas lasers

 

[Bratan]

Thanks arytntha! I actually find it interesting, but 2 days ago I almost put it on ebay. Now after reading thru these forums and on HeNe lasers in general not so sure I'm itching to take it apart and see how light gets pumped in the tube. Maybe I can take some interesting pictures/videos of it... Do you know if power supply can be used with a bigger HeNe tube that's generates more output? BTW I didn't know key-chain lasers are underpowered, interesting stuff!

 

[ElektroFreak]

In HeNe lasers, light is generated inside the tube rather than pumped in like diode- and lamp-pumped lasers. It's basically a very narrow, straight neon sign tube with a little helium added and a mirror at each end.

 

[Bratan]

In HeNe lasers, light is generated inside the tube rather than pumped in like diode- and lamp-pumped lasers. It's basically a very narrow, straight neon sign tube with a little helium added and a mirror at each end.

Ah ok I have no idea how semiconductor lasers work, but I remember from high school a model of ruby rod laser that had one half reflective and one fully reflective mirror on both sides, I guess gas laser works in the similar way. Found a nice article which I'm reading right now: Sam's Laser FAQ - Helium-Neon Lasers

 

[aryntha]

The power supplies are usually fairly closely matched (current, mA) for a specific range of tubes. You could probably power a slightly higher output head with it, but I'd research it first; it's not the laser head yo'ud be likely to destroy though, it's the power supply.

Keep in mind there's 1700-3500v coming out of these things so do be very careful.

 

[roddenberry]

...Found a nice article which I'm reading right now: Sam's Laser FAQ - Helium-Neon Lasers

Glad you're reading this! Our good friend Sam G. is pretty much the undisputed guru of all things that lase. His LaserFAQ is a true resource of accurate technical data on nearly all gas lasers and power supplies. It's a good primer also to learn the concept of operation of gas lasers .

Robert

 

[ShaOwned]

The HeNe laser works like this: There is a mixture of Helium and Neon in the innermost tube. About 70% Helium, 30% Neon I believe. Then the Helium atoms are pumped with energy to match the energy state of the Neon atoms. Collision then transfers the energy to the Neon, which emits a photon of wavelength 632.8 (usually). Then a few of these photons get trapped between the HR (high reflector) and OC (output coupler) mirrors. As these photons travel back and forth, others also travel parallel with those photons. During this process the output coupler, a mirror with a transmisison of maybe 1% or so, allows a small percentage of light to escape - that's the light you see.

Incase you were wondering how it works. HeNe's are really cool - it's a fun project to build one if you ever get the chance too. You can do alot of cool stuff with an external mirror cavity.

 

[jmgallego]

HeNe's are really cool - it's a fun project to build one if you ever get the chance too. You can do alot of cool stuff with an external mirror cavity.

Yeap... that is how I got into lasers. I built my first HeNe back in 1973, the sensation one gets when the first beam appears, is indescribable, that thin 632.8nm red-orange straight beam coming from what you built was so impressive. I am guessing it was <5mW. Later I bought one from Edmund Scientific and used it to learn about optics, physics, etc. But eventually I got hooked with holography and quantum chemistry experiments.

So, enjoy it, learn from it. It is a relatively safe laser and the best way to learn to create your own holograms.

 

[JLSE]

Can it's power be increased or is it pretty much worthless piece of antique tech?

It is *brighter* than a $3 keychain laser, as its 632.8nm (more of an orangish red) vs the keychain laser's 660-670nm deep red. So not neccessarily more powerful (though granted, most "5mW" keychain lasers are actually 2-3mW, whereas this is likely actually 5mW).

It will appear ~3-4x brighter at the exact same output.

You can do holography with it, if you're into that sort of thing. You can't increase its output, unfortunately. It's output is based on the size and length of the physical bore.

And if you don't find it interesting, I'll buy it from you for $15 and you'll make a profit I like gas lasers

Just for the record and safety's sake, I have had dollar store key chain pointers test up to 11mW on full batteries. Got to be careful with China products and assumption when your eyes are involved...

You can also squeeze a bit more power out of a HeNe by surrounding or lining the tube with magnets in a certain fashion. I have also heard of some tubes being bought with magnets already in place, though I have not personally tried nor seen this up close.

IIRC its called the 'Zeeman effect', but am probably wrong, possibly LaserFAQ can chime in on this. There is some reading here about boosting output via magnets..

http://www.jklasers.com/HeNe/HeNe_Laser_Report.htm

If one thing is for sure, the HeNe's beam quality is far superior to any low cost LD ive seen. I bought a case of 635nm diodes some time back and all the ones I assembled looked nothing like a HeNe's beam other than the orange tinted dot. Though im sure there are some that may come close, just never seen it personally.

 

[ShaOwned]

If one thing is for sure, the HeNe's beam quality is far superior to any low cost LD ive seen. personally.

The HeNe is well known for it's beam quality. Usually they have close to 1 M^2 and very low divergence. Considered the best quality beams. That's why they are often used for alignment.

 

[iwannapony]

wait you went to a garage sale and bought a gas laser. and people are just ok with that. where do you live that people just have gas lasers laying around for 5 bucks.

 

[aryntha]

Yeah... No kidding. I can search the entire town here in an entire weekend at garage sales and find nothing but used baby supplies and Captain and Tennille records.

Consider yourself pretty lucky, Bratan.

(Maybe he lives in a college town, or a town with research labs in it?)

 

[jmgallego]

wait you went to a garage sale and bought a gas laser. and people are just ok with that. where do you live that people just have gas lasers laying around for 5 bucks.

We live in Eureka :yh:

(Get it? Eureka, as in the TV show) :crackup:

 

[Mickey]

Man, I remember those days... I lived on HeNe. I was so freaked out when I started using my <5mW HeNe at my bands live shows... we were SOOOO cool. Hang on to this laser! Put it away, and maybe 50 years from now John Titor himself will come back in time and need it for a build!

 

[aryntha]

Put it away, and maybe 50 years from now John Titor himself will come back in time and need it for a build!

Man. I thought nobody would mention that guy ever again. But Titor only deals with the bendy, floppy sort of light.