Linguofreak
Well-known member
That is like saying that a radiator wouldn't work if you put a color and polarizing filter and a long tube in front of it. You might lose some efficiency, but it still works.
It would actually work fairly well, but it wouldn't produce the same effects as a laser. You see, for one, all the photons in a laser are in phase with each other, which your arrangement can't do. For another, something has to happen to the energy the filter and tube prevent from escaping. Generally, that energy will cause the filter and tube to heat up to the temperature of the radiator (or a bit less, considering that they'll be letting some of the radiation from the radiator through), at which point they will let off the same blackbody spectrum as the radiator. So you'll still get a blackbody spectrum eminating in all directions, just as if you had the radiator there by itself.
If you want to let off just one frequency in one direction, you'll have to refrigerate the tube and filter assembly. Refrigeration requires energy. You have to generate that energy somehow, and any inefficiency in generating that energy will add to the amount of heat you have to get rid of.
The stimulation at the chosen frequencies of the maser might make up for the polarization inefficiencies and frequency change to make it practical, but it might not. If it gives off light (energy) and is powered from the energy of a hot object, it cools the object.
Not if sending the energy away from the object by that method requires more energy from a battery or an outside power source than it sends away.
Also, in the specific case of that Brin novel, the environment is hotter than the ship you're trying to cool. So you can't use the thermal energy of the ship to provide power for your cooling mechanism.
Also the laser ice cube is not a real object. Laser beams diverge significantly at a distance equal to its initial beam diameter squared.
Proportional to beam diameter squared, not equal. Wavelength is also a factor in diffraction.
This is due to quantum effects. If you apply quantum effects to the ice cube, you will find that the molecules in it aren't perfectly still even at absolute zero. The fact remains that the entropy is very low.
Its going to get spread out across space-time curves and quantum changes.
And as I mentioned before, it will also heat up and be scattered by anything it hits, but, in that case, as well as this, that involves what happens to it later, not the process involved in creating the beam.