Effective use of natural sunlight in a habitat.

--- Ian Woollard wrote:

> On 24/07/07, Xenophile
> wrote:

> > Also, I'm not talking lasers, just so there's no
> confusion.
>
> You are, because there's NO optical way to turn
> ~1kW/m^2 into 8MW/m^2
> using mirrors or lenses; there's an optics theorem
> that states that.
>

It can be done with non-imaging optics. I hooked up a
36" x 27.75" (914mm x 705mm) Fresnel lens and got the
focus down to about an quarter of an inch diameter, a
magnification of over 20000 times. When we put a
quarter-inch-diameter bundle of light fibers at the
focus, they carried the light just fine; we did a
little woodburning with the other end. I have melted
rock and boiled steel with this lens, so we're going
to do some more detailed experiments in a couple of
months to quantify the losses per meter of fiber,
determine maximum energy density and so on.

Ed