Yeah, that's what I'm saying? You'd lose a lot in conversions with the laser setup, but you'd gain flexibility and the setup would be far more compact.
Doesn't read that way. Where your first statement was "That just looks like a laser furnace with extra steps", I'd say what you proposed looks like Odeillo with lot of extra steps. Focusing sunlight with mirrors is strictly simpler.
I don't suppose you guys bothered to read the second line then?
Regardless, I would still argue that setting up some panels and connecting them to a laser is fewer steps than setting up an array of carefully aligned mirrors and constructing a whole other building of mirrors that focus bounces from those into a point.
Typically solar panels are 21% efficient and lasers are 10% efficient, so the panel+laser setup is about 2% efficient. The mirror setup can be 70% efficient, depending mostly on your absorber design.
Building a laser normally also requires carefully aligning mirrors, as well as typically other advanced processes like glassblowing and high-voltage arcs (for low-pressure gas lasers) or glassmaking with high transparency and carefully controlled doping (for solid lasers), and in most cases fairly advanced chemistry. You might be able to make a laser out of fluorescein-doped jello, for example, but where do you get your fluorescein? It doesn't grow on trees.
Of course you can just buy a laser off the shelf, in which case you don't have to mess with any of this, but you can also just buy a big Fresnel lens off the shelf.
People have been polishing metal into mirrors for 6000 years, and as I understand it, the mathematics of parabolic reflectors for burning things was known by Euclid's time, 2300 years ago, which is probably why the English word for the point where the rays meet is "focus", Latin for "fireplace" (though that sense of "focus" may be only 400 years old).
Newton was making fairly decent-shaped parabolic mirrors 354 years ago, and interferometry has been good enough to make parabolic mirrors essentially perfect since about 01851.
The great limitation on these processes was historically the cost of materials: from Mesopotamia to Newton we're talking about various shades of copper or bronze, which are very expensive materials. For optical concentrators you don't need such optical perfection; gold leaf on something like polished stone would probably be cheaper, but in the Victorian age we learned the art of silvering glass with mercury, and in the early 20th century we learned the art of vacuum-silvering with silver, gold, or aluminum.
Ancient Egypt evidently made polished stonework on lathes, but may not have had the mathematical sophistication to make paraboloids of revolution, or to know why they were important. And the compound parabolic concentrators which allow you to not have to track the sun precisely are, I think, from the 20th century.
So, you might say, why didn't we have solar furnaces before the Industrial Revolution? Well, actually, before being murdered by the French Revolution, Lavoisier discovered that diamond was a form of carbon by burning diamonds in a solar furnace, in 01772. The solar furnace was crucial for this experiment not only because it allowed him to reach especially high temperatures but because it didn't introduce carbon dioxide.
Lavoisier's solar furnace used a lens like Seegers's, but enormously heavy and thick. Fresnel wouldn't build his first Fresnel-lens prototype until 01820.
