4 ms·

If sticking to a single frequency, the main loss is in producing the light in the first place as the new fibers can take a lot of power and conversion from ligh

If sticking to a single frequency, the main loss is in producing the light in the first place as the new fibers can take a lot of power and conversion from light back to electricity can get above 90%, but laser efficiency is still pretty crap.

api 8y ago
If laser efficiency were good enough for this we would have laser fusion.
- starbeast 8y ago
  I didn't realise that the laser's inherent inefficiency was the main loss in laser fusion, though it would make sense.
  - api 8y ago
    Laser fusion is not over-unity because lasers are horribly inefficient. If lasers were significantly better we could generate fusion power by repeatedly laser-imploding pellets of D-T fuel. We can already generate fusion this way but it takes more power to run the lasers than you get from the fusion (after conversion losses).
    - starbeast 8y ago
      That's interesting. So effectively, laser fusion shifts the problem domain into making a better laser, rather than all the tedious mucking about with plasma confinement. Will be interesting to see which problem is more tractable in the long run. Efficient lasers presumably have many more commercial applications than good plasma confinement does, though I could be very wrong about that. Given that the universe appears to have a sense of humour, efficient lasers will probably require progress in good plasma confinement.
      - api 8y ago
        Yes, though there are some other problems too. Laser fusion basically gives you a series of small thermonuclear blasts. There are ways of confining these (like doing them underwater) and extracting heat/power, but a real power plant would probably take some engineering and might have to be rather large. You could think of such a power plant as something like a thermonuclear internal combustion engine with laser spark plugs. Actually I wonder if giant pistons similar to the huge diesels built by Wartsila and others for container ships could work. Put some water in there with the fuel pellet and the water would be flash vaporized by the fusion yield. You'd be talking about a pretty massive engine bore, probably much larger than those monster diesels. Might be worth doing for sheer awesomeness. :) I don't know the numbers but my guess is that lasers would have to be dramatically more efficient than they are today for this to be a practical and economical way of generating power.
        starbeast 8y ago
        >Actually I wonder if giant pistons similar to the huge diesels built by Wartsila and others for container ships could work. You just reminded me of this mental steampunk fusion design I read about a while back - https://www.technologyreview.com/s/414559/a-new-approach-to-fusion/ https://www.technologyreview.com/s/414559/a-new-approach-to-...

api 8y ago

If laser efficiency were good enough for this we would have laser fusion.

starbeast 8y ago
I didn't realise that the laser's inherent inefficiency was the main loss in laser fusion, though it would make sense.
- api 8y ago
  Laser fusion is not over-unity because lasers are horribly inefficient. If lasers were significantly better we could generate fusion power by repeatedly laser-imploding pellets of D-T fuel. We can already generate fusion this way but it takes more power to run the lasers than you get from the fusion (after conversion losses).
  - starbeast 8y ago
    That's interesting. So effectively, laser fusion shifts the problem domain into making a better laser, rather than all the tedious mucking about with plasma confinement. Will be interesting to see which problem is more tractable in the long run. Efficient lasers presumably have many more commercial applications than good plasma confinement does, though I could be very wrong about that. Given that the universe appears to have a sense of humour, efficient lasers will probably require progress in good plasma confinement.
    - api 8y ago
      Yes, though there are some other problems too. Laser fusion basically gives you a series of small thermonuclear blasts. There are ways of confining these (like doing them underwater) and extracting heat/power, but a real power plant would probably take some engineering and might have to be rather large. You could think of such a power plant as something like a thermonuclear internal combustion engine with laser spark plugs. Actually I wonder if giant pistons similar to the huge diesels built by Wartsila and others for container ships could work. Put some water in there with the fuel pellet and the water would be flash vaporized by the fusion yield. You'd be talking about a pretty massive engine bore, probably much larger than those monster diesels. Might be worth doing for sheer awesomeness. :) I don't know the numbers but my guess is that lasers would have to be dramatically more efficient than they are today for this to be a practical and economical way of generating power.
      - starbeast 8y ago
        >Actually I wonder if giant pistons similar to the huge diesels built by Wartsila and others for container ships could work. You just reminded me of this mental steampunk fusion design I read about a while back - https://www.technologyreview.com/s/414559/a-new-approach-to-fusion/ https://www.technologyreview.com/s/414559/a-new-approach-to-...