New to Gas; A Few Questions

[jkguest]

Hello all, I have recently gotten interested in gas lasers and was wondering if someone could point me in the right direction. I know pretty much nothing about gas lasers and have only done a little bit of reading but haven't found any building tutorials or purchasing tips for beginners. Could someone link me to a thread or a website with some information? Also I've heard a couple people mention gas lasers "zapping" you. What exactly does this mean? Thank you.

 

[LtKernelPanic]

Sam Laser FAQ has everything you'd ever want to know about lasers gas or otherwise.

Getting zapped is a very real possibility with gas lasers especially with bare tube Helium-Neon (HeNe) lasers such as the ones n my avatar. The tube acts like a capacitor and takes a while to self discharge after it's powered off. The shock is harmless in 99.99999% of people but will hurt like hell (think of the worst static shock you've ever had) and could cause you to drop and break a tube you were trying to pick up. There are ways to discharge it quickly such as shorting out the leads coming from the tube if they're not permanently connected to the PSU or you could always wear gloves to insulate yourself from it. I have a cheap pair of winter gloves I paid like $2 from the hardware store a couple years ago that work fine for when I need to move a tube that's been recently run. Any cheap work gloves should work fine as long as they don't have a real loose weave that could allow an easy path to ground for the tube.

Touching a running tube is also a very bad idea because the smallest tubes typically draw about 1200VDC at 3mA (the large green HeNe in my avatar requires 2750VC @ 6.5mA) which again wouldn't cause problems in 99.99% of people because of the resistance of your skin but it only takes a few millivolts across your heart to stop it. Larger gas lasers such as my multiline argon have voltages and amperages in different parts of them that could easily do some serious damage to you. Other lager gas lasers can use 220/240 single phase power and yet others even require 3-phase which is another whole level of danger.

All that said gas lasers can be quite fun and enjoyable for the laser enthusiast but be warned they can be expensive and you need to be careful when buying them from places like fleabay. Asking here first is a good idea if you're unsure if an auction is worth it or not and people here pretty much always respect "dibs" on an auction.

 

[pschlosser]

The risks of being shocked varies with the type and configuration of laser.

A Helium Neon (HeNe), for example, sealed inside a metal tube with end caps in place (very common configuration) poses the least risk, in my opinion of being shocked. With that said, I have only ever been shocked by HeNes. But they were out, on the bench and exposed. I was tweaking the power supplies and I got careless.

The shock is really decent at 2K volts, with more intensity than being shocked by household current at 110v. But the current is tiny, so it does little lasting harm. Being shocked by 110v with enough current is worse.

Most gas lasers are configured in a "lab laser" setup, which means they do not run on batteries, but plug into a power supply that, in turn, plugs into the wall. They are pretty safe. Just remember, the bulk of gas lasers use high-voltage electricity to excite gasses to a degree that they cry out in wavelengths of light.

But, they've been making gas lasers for decades, and there are several around in varying states of operation. Hobbiest like us want to save money, so we may buy a broken one, or try to improve a mediocre one, and begin opening it up and monkeying around with it. The dangers of working on a laser power supply are very similar to working on a CRT television. It's unclear how many deaths per year can be attributed to electrocution by television, but I imagine it's pretty small.

It is wise to be cautious if you're able to touch parts of the laser normally protected by an enclosure. But unless you have a weak heart or running on a pacemaker, I do think there is much to be overly paranoid about.

Good question.

 

[jkguest]

Thanks both of you. I plan to start with just buying a small HeNe before trying to build one. Would you guys have any suggestions of where to buy from? I preferably would only want something 2mW-5mW of any color. Preferably reasonable price but won't say a budget because I don't really know how expensive HeNes are and don't want to seem like some of the noobs who ask for something crazy powerful and expensive and say they want to spend only like ten dollars. Also, do the same eye safety rules apply to gas lasers? If you do need eyewear, would you need something special for gas lasers or do safety glasses not diffrentiate between diode and gas? FInally, is the output of a gas any brighter than its equivalent diode of the same power and wavelength? Sorry for so many questions haha.

 

[pschlosser]

gas lasers are on the expensive side, and laser diodes are taking over, in terms of price. especially if you look at it in terms of price per milliwatt.

If you want to produce light in pretty colors, laser diodes are going to be cheaper than gas lasers. But if you're set on gas lasers, this forum is one place to keep checking. Another is ePay.

Red HeNes are the most common gas laser and cost the least. Budget $100 for a HeNe that produces under 5mW. But there are green HeNes (quite a bit more rare) that come in at twice the cost. Yellow HeNes, even more rarer still, at twice the cost, again. And orange ones, the most rare, at twice the cost, again.

Shop around. There are some pretty tall asking prices for lasers on FleaPay, but if you watch, you can find something in your price range.

 

[jkguest]

gas lasers are on the expensive side, and laser diodes are taking over, in terms of price. especially if you look at it in terms of price per milliwatt.

If you want to produce light in pretty colors, laser diodes are going to be cheaper than gas lasers. But if you're set on gas lasers, this forum is one place to keep checking. Another is ePay.

Red HeNes are the most common gas laser and cost the least. Budget $100 for a HeNe that produces under 5mW. But there are green HeNes (quite a bit more rare) that come in at twice the cost. Yellow HeNes, even more rarer still, at twice the cost, again. And orange ones, the most rare, at twice the cost, again.

Shop around. There are some pretty tall asking prices for lasers on FleaPay, but if you watch, you can find something in your price range.

Ok thanks. I got seem to find epay though. And on flea pay I cant seem to find a way to search for items. Also when you said I should check the forums, do you mean the buy and sell section?

 

[pschlosser]

Ok thanks. I got seem to find epay though. And on flea pay I cant seem to find a way to search for items. Also when you said I should check the forums, do you mean the buy and sell section?

yes, I mean the B/S/T forums.

Also, I meant eBay, not ePay or FleaPay. I was trying to make fun of the eBay name , but not confuse you. Sorry.

 

[jkguest]

Oh haha. Sorry Its hard to pick up sarcasm without hearing it. And on the care and use of HeNes, do you have to run them every once and a while to keep them working? Do they have duty cycles? How do you turn them on (just flip a switch or is there a series of something you have to do? Also, is the brightness and capability the same as a diode of the same power?

 

[pschlosser]

Oh haha. Sorry Its hard to pick up sarcasm without hearing it. And on the care and use of HeNes, do you have to run them every once and a while to keep them working? Do they have duty cycles? How do you turn them on (just flip a switch or is there a series of something you have to do? Also, is the brightness and capability the same as a diode of the same power?

wow. good questions.

They have a decent shelf life. They do degrade a little if left on the shelf, but at a much slower rate that others, such as Argon. But you can let them sit for months or years without to much concern.

Duty cycles? No. They can be run continuously, more or less. HeNes are really quite stable.

Turn them on by plugging them in. Many do not have switches, but you can add one if you prefer.

The brightness will be the same, if comparing to a laser diode of the same power. And they are just as good, in terms of beam quality as a LD. In many cases, the beam quality is better. Nice and tight beams producing a stable dot and output. The only real downside of a HeNe compared to a lab laser diode is its size.

 

[Cyparagon]

do you have to run them every once and a while to keep them working?

That depends on which ones. HeCd and ion lasers, yes.

Do they have duty cycles?

That depends on which ones. Generally, no.

How do you turn them on (just flip a switch or is there a series of something you have to do?

That depends on which ones. Some turn on when you plug them in; others need any or all of the following: switch, key, interlock(s), water line, water pump, and enable signal(s).