Tube Length vs Wattage

Just curios if “all” manufactures tubes are same length for equivalent wattage?

Wonder, if say in several years, we could buy the same length tube we have now, with higher wattage due to technology advances.

Here’s some averages

So the short answer is no. Actually sealed gas CO2 tubes have been in usesince the mid to late 80’s on the medical side. When I started as a Field Tech we used flowing gas tubes until the late 80’s when we swapped to sealed gas. Cheaper to run but not anywhere near as stable output as a flowing gas laser. Tube length verses power and somewhat diameter ( though I think that affects gain more…but been a while)…has remained the same for 40 years.
There is a whole physics thing that determines power verses tube length so it will not change…physics determines the tube length. I wish I could recall it all but when it was explained to me, in depth, by a PHD who worked in our R&D lab my eyes went cross eyed…I started to drool and blanked out. I lost him about 5 sentences in. Truthfully I do remember the basics of it so I got the basics which was all service guys needed.

Basically one of the factors is cascade amplification or cascade effect…forget the proper term. But when you excite the laser gas with the HV from the power supply it excites the Co2 into a higher energy state. However the co2 gas can’t stay at that excited state and will return to its normal rest state. As it falls from it’s excited state it passes through like an unstable region and a certain number of Co2 atoms will emit a photon of light. This photon will travel down the tube and hit one of the two mirrors. the rear mirror reflects 99.9% of the photons back up the tube. When they hit the front mirror somewhere roughly around 20% (give or take) will leak out and the balance is reflected back again through the tube to the rear mirror. As they travel back and forth these photons will lets say strike or excite other atoms forcing them to emit a photon and so on. This back and forth is where you get the cascade amplification and is where your power comes from. You get squat from just pumping voltage to the tube. If you let 100% of the photons to leak out your front mirror you would get basically 0 power.
So this back and forth travel between the two mirrors is your power and the longer the tube the more photons we can get to “strike” since we have a longer beam path and more gas.
Tube diameter is more of a gas storage thing. You cannot get the Co2 gas back to an elevated state immediately it has to stay at rest for a certain time. Don’t ask me I don’t know…probably milliseconds but I have no clue. But you need to have lets say fresh gas to excite so a larger diameter tube stores more gas
Also sealed gas tubes are limited in max power to about 150 watts maybe a tad more. Beyond that you usually run into a flowing gas tube to get the higher powers. Maybe there are 200 watt sealed tubes not sure but when you get much higher it is flowing gas.
But suffice it to say…no. They have been almost exactly the same for 40 years although boy they have dropped in price. A sealed gas tube in 89 for a 50 watt tube about 4-5K.

If I have made a slight error in explanation well…hey man it was the mid 80’s…I was 25 and having fun…lucky I have any memory:-)


Hehehe. ROFL Hilarious.

Great reply Scott. That makes a ton of sense, and def makes me respect the tech more.

Well one could hope and wish for more pwr.

I do at least like the new inline red dot tubes, and will get one if I ever have to buy a tube.

Excellent explanation. I started to drool and blanked out tho. Am I doing it right?

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Yah I want to upgrade to an integrated tube with the red beam as well. Much better than having a diode laser hanging off the nozzle that at best is close to the burn but never quite spot on.

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