I just saw a YouTube video by someone with 2000 W laser and now I wonder how can the laser not melt itself when compared to a lense bundeling sunlight its always said cannot get hotter than the sun itself?
In: Physics
The sun is a “blackbody” radiator, it generates light based solely on its own temperature, which is hot.
A laser works differently, and a little complex for an ELI5. Basically it’s using a very specific interaction in a specific type of gas molecule to generate exactly one color of light and nothing else.
The lasers interior is highly reflective at this wavelength so most of it gets beamed out instead of absorbed and converted into heat.
The rust is very absorbing at this same wavelength and heats up intensely.
That said, powerful lasers do get extremely hot. It’s probably water jacketed and/or covered with extensive heatsink fins so that it doesn’t overheat during continuous operation.
The laser emits light by a different process than most normal things, there is still a limit to the temperature you can achieve with a laser but it’s much higher than for traditional light sources.
Lasers do get hot and big lasers are typically water cooled because of that but that’s due to inefficiency.
The laser isn’t transmitting heat. You are correct that you can’t transmit heat to get something hotter than the original source.
It transmits pure light, which the rust then converts into heat.
The sun transmits heat, through blackbody radiation like /u/Lithuim said.
Been on that StyroPyro content, eh? 😄 i had the same question, glad you asked.
Edit:Typo due to lack of brain cells.
Lasers do get hot, they have cooling systems. Small laser pointers can use passive air cooling. Powerful industrial lasera need active water cooling.
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