I assume my first gas laser will be a HeNe because they aren't too big and are reasonably priced. I am just wondering how does a HeNe differ from a HeCd. Also I hear about huge argon lasers that take up a huge amount of room and require tons of power. Are there such things and smallish argon? I'm taking making 20 pounds rather than 200 pounds. I'm just curious and I am thankful for any input.
Also I just checked my local Craigslist and someone posted a HeNe laser for sale. I text them and got the model which is a uniphase model1508-0. He says it seems to work fine. I'm assuming this person doesn't know much about this laser. What would a good price be? Before I say how much he is asking I want to see what people say it's worth about.
I am appreciative for any feedback.
Thanks,
The major difference between a HeNe and a HeCd is of course the lasing medium.
In a HeNe, there is an arc travelling through and ionizing the HeNe gas mixture, resulting in the atomic transition of the electrons. Resulting in the release of photons. These photons are then trapped by mirrors to allow them to resonate. Resonation occurs when a photon travels from it's place of creation, to a mirror, and then back.
When this light is allowed to a resonate, a "pool" of light forms. About 1% of this pool is allowed to exit, resulting in coherent light
The larger the cavity, the more gas, the more light. Or widening the bore, though this results in multimode output. That's a whole other story...
A HeCd is a tube using helium gas, and cadmium metal. The helium atoms are energized by the discharge (somewhere in the ballpark of 1500V) and then these atoms transfer this energy to the cadmium. This process takes a while to vaporize, and ionize the cadmium. This means that warm up for these tubes can be upwards of 10-15 minutes or more.
Though the helium is evenly dispersed, the cadmium is a chunk on the positive side more or less. The negatively charged ions however tend to travel towards the cathode. In a poorly made tube, this can degrade the cathode, and even damage the mirrors. In well designed tubes, there will be a cold trap to cool and trap these ions, and over time there will be a noticeable displacement of the cadmium from the cadmium well, to the cold trap.
Argon lasers!
Argon can be VERY large. I saw a 15W tube (maybe even more) at SELEM that took up the entire length of a pop up table, and half the width. The PSU took up about a yd^3 on the floor. These are run off of 3-phase power, and are water cooled. They are MONSTERS. I saw a running white-light also, equally large and beastly.
Though they can also be much smaller. The "small-framed" air cooled argons that most argon hobbyists own take up about 18"x5"x4". Their PSU has a similar profile. These are generally 110V air cooled, but some can be 220/240. Generally not though for the "small-frame" class.
Kryptons follow the same guidelines as above. However most are water cooled "large-frame".
Your Craigslist laser!
This is a "Novette" self contained tube. I personally wouldn't pay much for it. Though if you just wanted a tube and PSU all in one, and didn't want any more work beyond plugging it into the wall, then this is for you.
You won't see any plasma from it, just so you are aware.
I'd say about $50-65.
These run from DC wall adapters, so see what you need to power it, and get an adapter for it.
