Science quiz of the day: lasers

[James Snover]

Lasers are everywhere, today, used for scanning barcodes at the grocery store, initiating fusion in laser inertial confinement reactors, to chemical lasers that fill the belly of a 747 and shoot down ICBMs.

What makes a laser different from ordinary light?

Who first had the idea this could even be done?

Can a laser be a naturally occurring phenomenon?

Bonus:

Is a laser always a beam, or can it be omnidirectional, like ordinary light?

 

[oldmodman]

The light is coherent.

It was first created at the Bell Laboratories in the end of the 50's and patented in 1960. The first laser was a polished ruby rod, excited by a zenon strobe tube surrounding it.
But Einstein came up with a theory of the possibility of the laser way back in the teens.

Sorry. I can't answer the third question without cheating.

 

[nxhappy]

just gonna put this right herez:

 

[bullitt2735]

Speaking of lasers, that's what I will be rebuilding today. Fixing and realigning.

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[DHG1078]

Laser light is coherent, monochromatic, and colluimated. Meaning it is one specific wavelength vs "regular light" being composed of all wavelengths, in phase in both time and space, and travel parallel to eachother. So laser light travels in one specific direction, like a beam.

The wavelength of each laser is dictated by the quantum mechanics of the various materials used to create lasers.

 

[capnkirk52]

Bonus for you Jim.... I need a practical application seed potato laser cutter that will run on no more than 480V. We could do 220V if that works, too. Fresh cuts every time will reduce disease levels drastically.

You can google specific gravity of potatoes and the temps will generally be in the 40-50 degree F range.

https://www.google.ch/patents/US6321484 is the link to the expired patent. I already have a high pressure water jet cutter but a laser would be dope.

 

[James Snover]

Laser light is coherent, monochromatic, and colluimated. Meaning it is one specific wavelength vs "regular light" being composed of all wavelengths, in phase in both time and space, and travel parallel to eachother. So laser light travels in one specific direction, like a beam.

The wavelength of each laser is dictated by the quantum mechanics of the various materials used to create lasers.

Mostly correct. Laser light does not have to be colimated.

 

[James Snover]

Bonus for you Jim.... I need a practical application seed potato laser cutter that will run on no more than 480V. We could do 220V if that works, too. Fresh cuts every time will reduce disease levels drastically.

You can google specific gravity of potatoes and the temps will generally be in the 40-50 degree F range.

https://www.google.ch/patents/US6321484 is the link to the expired patent. I already have a high pressure water jet cutter but a laser would be dope.

Interesting. When using lasers to cut, maximum effectiveness is obtained when the object being cut is the complimentary color of the light being used. This assures maximum transfer of energy. Since potatoes are mostly white, I'm guessing blue or ultraviolet would be best, since you can't get a complimentary color to white, then go with as high a frequency of light as you can get. Both blue and UV would present major workplace hazards as scatter from both at the energy levels needed would be harmful to the eye.

You could also go with X-ray lasers (my favorite!) but then you've really got regulatory issues and the power requirements are off the charts, way past 480!

 

[James Snover]

Interesting. When using lasers to cut, maximum effectiveness is obtained when the object being cut is the complimentary color of the light being used. This assures maximum transfer of energy. Since potatoes are mostly white, I'm guessing blue or ultraviolet would be best, since you can't get a complimentary color to white, then go with as high a frequency of light as you can get. Both blue and UV would present major workplace hazards as scatter from both at the energy levels needed would be harmful to the eye.

You could also go with X-ray lasers (my favorite!) but then you've really got regulatory issues and the power requirements are off the charts, way past 480!

Or you could try and get a surgical laser. Those are around forty watts output, which doesn't sound like much, but trust me, forty watts confined to a pin-point is a lot and just might do the job. And they're commercially available. Still going to need eye protection against scatter!

 

[cbj5259]

After reading through this thread I realize how dumb I really am.

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[bullitt2735]

forty watts confined to a pin-point is a lot

Yupp! The above laser I rebuilt today is an Nd:Yag laser used for jewerly it welds gold, steel, platinum and its only 35 watts I believe.

 

[capnkirk52]

It's gotta be fast though. How many times can you split the beam? Here's the current way that most people cut.

<iframe width="560" height="315" src="" frameborder="0" allowfullscreen></iframe>

 

[DHG1078]

I think speed would be a problem. It would probably take a massive amount of lasers to keep up with your traditional equipment. Operational and maintenance costs will skyrocket too, I would imagine.

I have wanted to get lasers into my manufacturing plant for a while, but I can't justify the expense. They are crazy expensive for the products I work with, I would need a 2-in-1 laser to work on my laminates, and they are SLOW compared to traditional drill/route machines. Partly because I need equipment capable of cold ablation and it often takes multiple passes to make one cut. The only time a CNC can't compete is when the feature size gets very small, i.e. sub 6 mil, as thats about as small as drill bits get. There are many advantages we could use one for, but it just can't compete cost wise currently.

Thats not even considering maintenance and operation costs as those are sky high compared to our current equipment also.

 

[capnkirk52]

Damn. Wish there was something out there.

 

[James Snover]

It's gotta be fast though. How many times can you split the beam? Here's the current way that most people cut.

<iframe width="560" height="315" src="" frameborder="0" allowfullscreen></iframe>

You can split the beam all you want, but with every split is a reduction power.

 

[Dsg-shaker]

Or you could try and get a surgical laser. Those are around forty watts output, which doesn't sound like much, but trust me, forty watts confined to a pin-point is a lot and just might do the job. And they're commercially available. Still going to need eye protection against scatter!

Is it the same as a plasma rifle, since they are in the same wattage? 1:

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[James Snover]

Is it the same as a plasma rifle, since they are in the same wattage? 1:

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As an offensive weapon, a plasma might be better than a laser, especially a visible light laser. Reason being you can deflect, or at least greatly limit the energy delivery, of a laser with a mirror. You can also limit the energy delivery if whatever you are shooting with a laser happens to be the same color as the laser. (Note: this is in regard to ordinary surgical-style 40-1,000 watt lasers. You start talking about the chemically pumped laser in the 747 that is being used to shoot down ballistic missiles, ALL of that goes pretty much right out the window). Plasma? You might have to worry about it going to ground, but it wouldn't have the other limitations of low-powered lasers.

 

[James Snover]

Yupp! The above laser I rebuilt today is an Nd:Yag laser used for jewerly it welds gold, steel, platinum and its only 35 watts I believe.

neodymium-yttrium-argon? I'm jealous!

 

[derklug]

All this time I assumed they were developed just to amuse cats.

 

[bullitt2735]

neodymium-yttrium-argon? I'm jealous!

Close! Neodymium doped ytttrium aluminum garnet. They are used mainly for welding and repairing small holes. We also have some small fiber laser for engraving and some c02 lasers as well that I'm responsible for.