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Right, but that point would be exactly as hot as the surface that the light was coming from, and no hotter.

(Is the argument as I understand it).

If this is true, how do laser cutters work? The focused beam can melt through steel, but surely the temperature of the gain medium is much lower than the melting point of steel?

But the thermodynamics argument seems like it makes sense too...

Lasers have negative temperature. The light emitted from the sun is nothing like laser light.

https://en.wikipedia.org/wiki/Negative_temperature#Lasers

Like the other commenter said, lasers are not black-body emitters. They "pump" light out and are very far from equilibrium.

Wouldn't that kind of make the National Ignition Facility [0] impossible?

0: https://en.wikipedia.org/wiki/National_Ignition_Facility

From what I've read in the other comments, the argument doesn't apply to lasers.

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