mw to temperature

[jamilm9]

does any one have a chart showing a comparison of mw to temperature on a black surface.

 

[JECS]

? it would vary on a lot of things.. the shininess of the black surface. the flatness/smoothness of the surface. the size/focus of the beam. also the number of beams would also be a factor. distance would also make a difference..

 

[Switch]

The main factors this would depend on are irradiance(power/surface or mW/mm[sup]2[/sup] if you want, the energy absorbsion of that particular black surface as I'm sure not all black surfaces absorb the same quantity of energy, the ability of that particular material to dissipate the heat it's gathering(a small black piece of metal would probably heat up more than small black piece of metal attached to a huge heatsink) and the temperature the black surface already has.

I was able to make a drop of water make sparking noises(I assume that it started to boil ) pretty much instantly with my DIY laser.I'm estimating the power of my laser at somewhere between 100-130mW(or a little more with batteries out of the charger).The beam diameter was way smaller than 1mm(estimating 0.3 or 0.2 as I can't really measure).The drop of water was put over a black ,non-shiny cd-case.So under these circumstances I guess that my small ~0.3mm dot reached a temperature of over 100[sup]o[/sup]C (or 212[sup]o[/sup]F if you want)

 

[jamilm9]

ok thanks

 

[philguy]

even assuming 100% absorption, there is heat flow and mass to be considered.

But if you just say "I have a totally black iron cube, 1cm³, and I shoot at it with 500mW for 10sec", then temperature rises 1.4K (or °C).

So if you could give us some more specific information, we might be able to help you a bit more.