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Gas Lasers? Tell me about them please :)
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diachi
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Gas lasers use a GAS lasing medium, opposed to a solid lasing medium for diode or DPSS.I only heard of Gas lasers when joining this forum but don't get them at all. They seem to be 0.5-5mW but cost ridiculous amounts; $100+ for a 1mW laser?
What's different about them to normal lasers and why are they so popular?
Thanks
Gas lasers can range into the kW power range. HeNe lasers are usually low powered 1-5mW. But some can range up to 200mW, they are very big. Argon lasers can range up to about 30W commercially, but require huge amounts of power ( 3 phase ) and water cooling. Smaller air cooled argons can reach 200mW and larger air cooled ones can reach 2W or so. Gas lasers can produce a wide range of lasing lines, for argon there are up to 8(?) in the visible range and many more for IR and UV. HeNe lasers are mostly red but Orange green and yellow HeNes exist. CO2 lasers which lase at 10,600nm are one of the most powerful gas lasers, common powers are 10W for smaller lasers,>100W is common. industrial uses are often in the kW range.
There are a magnitude of gas lasers. For more information you can look on Sams laser FAQ ( Search google.)
Hope this helps!
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diachi
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Just to add: Gas lasers usually always have a better beam quality than DPSS or Diode lasers. They are usually also more stable. Although recent developments in OPSL and Ring lasers may change that.
diachi
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30W?! that's got to be enough to like... burn through a building, or person or something
But what I don't get is the attraction of a 3mw HeNe laser for the same price of a 150mW standard. What can a HeNe laser do?
Sorry for being so noobieish
30W Will burn quite a lot of stuff, paper, wood, glass (Depending on the wavelength.) . 60W CW can punch holes in metal.
The beam specs on HeNes are far better than diode and the stability is better than DPSS, you can also get wavelengths that aren't so cheaply available in diode or DPSS such as 594nm and 612nm. Green DPSS lasers are cheaper than green HeNe lasers. There was also no viable alternative to producing more exotic wavelengths (594, 612nm etc ) until a decade or so ago,maybe less.
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My 2 cents, I agree 100 percent with everything that diachi has to say, but would like to add..
A green Helium Neon (HeNe) laser produces a more pleasant shade of green that is easier on the eyes, has NO stray IR waves to give you "welder eye" (that dry itchy feeling after exposure) the beam is round, tighter and diverges a lot less than a diode laser or cheap green pointer.
The red HeNe produces a shade of red that SEEMS brighter to the human eye due to the 632nm wavelength versus the 650-670nm of a diode laser.
A HeNe leans almost toward orange/red where a diode laser is more of a "ruby" red. A green HeNe is more emerald green, a diode (DPSS) green laser is more of a lime green.
There are pros and cons to each type, I like owning both types very much.
A green Helium Neon (HeNe) laser produces a more pleasant shade of green that is easier on the eyes, has NO stray IR waves to give you "welder eye" (that dry itchy feeling after exposure) the beam is round, tighter and diverges a lot less than a diode laser or cheap green pointer.
The red HeNe produces a shade of red that SEEMS brighter to the human eye due to the 632nm wavelength versus the 650-670nm of a diode laser.
A HeNe leans almost toward orange/red where a diode laser is more of a "ruby" red. A green HeNe is more emerald green, a diode (DPSS) green laser is more of a lime green.
There are pros and cons to each type, I like owning both types very much.
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GooeyGus
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It's not always about power
Some of my favorite lasers are the lowest powered lasers I own.
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It's not always about power
Some of my favorite lasers are the lowest powered lasers I own.
Excellent answer!
Try getting the shades of blue that a good Argon will produce from a diode.
By the way, 20+ years ago HeNe was THE standard for hobby lasers. If you wanted one at all you had to search the back of "popular electronics" magazine for surplus tubes.
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You've made it painfully obvious that you have no idea what you're talking about, photonaholic.
That is entirely subjective.
Not usually. The divergence is generally worse, but that's because the beam is so thin at aperture.
Welder eye is caused by UV, not IR.
543nm is yellower (and therefore more lime) than 532nm.
That is entirely subjective.
Not usually. The divergence is generally worse, but that's because the beam is so thin at aperture.
Welder eye is caused by UV, not IR.
543nm is yellower (and therefore more lime) than 532nm.
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Having been on various forums for years, I am used to replies like that.
Personal observations - My HeNe makes a much tighter beam at 50 feet than any of my current diode lasers.
"Welder eye" is a term I made up to describe how the unprotected eye feels after exposure to the light, regardless of wavelength, and you are very correct, My assumption is clearly wrong, simply because the HeNe is a lot lower powered, it is less likely to irritate the eyes after long term exposure too scattered rays.
Sometimes it takes a reply like yours to kick start the old brain and shake out the cobwebs...
Can I blame the inverted descriptions on being half asleep late at night??
Personal observations - My HeNe makes a much tighter beam at 50 feet than any of my current diode lasers.
"Welder eye" is a term I made up to describe how the unprotected eye feels after exposure to the light, regardless of wavelength, and you are very correct, My assumption is clearly wrong, simply because the HeNe is a lot lower powered, it is less likely to irritate the eyes after long term exposure too scattered rays.
Sometimes it takes a reply like yours to kick start the old brain and shake out the cobwebs...
Can I blame the inverted descriptions on being half asleep late at night??
GooeyGus
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Well, diode lasers do have much worse divergence.
It may not seem like it, but you have to remember that every diode we use has beam correction optics to give it better divergence. As you know, gas lasers generally don't use any sort of optics. The beam comes directly from the cavity.
Now, compare a diode laser's divergence with no optics to a gas laser with no optics and the gas will win every time.
It may not seem like it, but you have to remember that every diode we use has beam correction optics to give it better divergence. As you know, gas lasers generally don't use any sort of optics. The beam comes directly from the cavity.
Now, compare a diode laser's divergence with no optics to a gas laser with no optics and the gas will win every time.
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I recently purchased a 50mw green DPSS from Aixis, I was all excited about it, then the day it arrived I took it down to the basement (50 feet long, no windows! perfect) and fired it up.
At 50 feet the "dot" was 12mm~14mm in diameter.
My old 1980's vintage HeNe makes a dot that is substantially smaller.
So I based my statement solely on that observation. (could be less than optimal optics in my green DPSS)
I just remembered that speaking in absolutes on forums can spark controversy, But that's OK, I wear "flameproof clothing" while online.
At 50 feet the "dot" was 12mm~14mm in diameter.
My old 1980's vintage HeNe makes a dot that is substantially smaller.
So I based my statement solely on that observation. (could be less than optimal optics in my green DPSS)
I just remembered that speaking in absolutes on forums can spark controversy, But that's OK, I wear "flameproof clothing" while online.
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I know it's not always about power, but spending £150 on a laser than the beam is not visible, is not easy to move around and can send the dot maybe 100m seems a little excessive.
You say harder to produce wave lengths can be made, are they adjustable (can I buy a HeNe or something that can make red, orange, blue and green for example)?
Not trolling or anything, just trying to get my point across that I still don't understand them
At the moment the £100 extra is justified by prettier colours and a tighter beam (lenses anyone?).
Thanks in advanced.
You say harder to produce wave lengths can be made, are they adjustable (can I buy a HeNe or something that can make red, orange, blue and green for example)?
Not trolling or anything, just trying to get my point across that I still don't understand them
At the moment the £100 extra is justified by prettier colours and a tighter beam (lenses anyone?).
Thanks in advanced.
diachi
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I know it's not always about power, but spending £150 on a laser than the beam is not visible, is not easy to move around and can send the dot maybe 100m seems a little excessive.
You say harder to produce wave lengths can be made, are they adjustable (can I buy a HeNe or something that can make red, orange, blue and green for example)?
Not trolling or anything, just trying to get my point across that I still don't understand them
At the moment the £100 extra is justified by prettier colours and a tighter beam (lenses anyone?).
Thanks in advanced.
The beam from my new <4mW HeNes is pretty visible, can see it easily without smoke.
As for HeNes that are tuneable - they are very rare. The lines a HeNe will produce rely not only on the optics but also the gas fill. So it's harder to tune a HeNe although some do exist. A lot of external mirrored argon and krypton lasers can be tuned with a tuning prism though. GooeyGus' 168 argon can be tuned with a tuning prism for example.
Argon is also currently the cheapest way for us hobbiests to get several watts of blue. Solid state is still far too expensive for us.
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Since the light that a diode emits comes from a point source, usually around 100 microns, the raw divergence is quite large. Because of this, a simple lens will allow for VERY low divergence from a single-mode diode since the effect of the highly divergent beam being collimated by the lens is that of a beam expander. By expanding the beam many times from the 100 micron source to a 2mmx4mm beam, the collimated output from the lens can be made to have divergence figures well below 1mrad.
GooeyGus
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I didn't say that diode lasers cant have good divergence, I was just saying that when you compare the lasers, apples to apples (bare cavities, no optics) the gas laser will always win :beer:
