Le 14/11/2013 21:20, Samuel Benge a écrit :
> clipka <ano### [at] anonymousorg> wrote:
>> Am 14.11.2013 19:23, schrieb Samuel Benge:
>>> "Anthony D. Baye" <Sha### [at] spamnomorehotmailcom> wrote:
>>>> if you could use the light to drive an actual laser, it might be even more
>>>> efficient.
>>>
>>> Has anyone ever converted direct sunlight into a laser? Or by "laser," do you
>>> actually just mean "parallel light beam?"
>>
>> Lasing media are typically pumped (i.e. supplied with energy to emit
>> actual laser light) by some kind of conventional light source - so why
>> not sunlight?
> 
> Never said it wasn't possible; I was just wondering it anyone had actually made
> it work :\ Also, why would laser light be better than simply using parallel
> rays?

Laser has 3 main characteristics (compared to normal light):
 1. parallel rays (due to the echo chamber, non parallel rays have been
eliminated) (well, the dispersion cone is very tight)
 2. single light-wave (at least very narrow spectrum, multiple rays are
possible but due to pumping it's always an atomic transition of the
electrons of the pumped material, unless a later frequency divisor is
used, or a first laser is used to pump a second one)
 3. synchronised phase of the photons

The destructive power (or heating) is far more efficient due to point 3.
Point 1 is just an easier way to a better control.

Analogy: lighting a point with normal light is like having a team of
basketball (or whatever your ball-sport), each with a ball, hitting a
movable target (let's use your favourite political leader of the wrong
party) at random time. You get effect but it's less effective than
having all the balls hitting at the same time. (the purpose being
obviously to have the target moving away with injuries)


-- 
Just because nobody complains does not mean all parachutes are perfect.

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Le_Forgeron <lef### [at] freefr> wrote:
> Le 14/11/2013 21:20, Samuel Benge a écrit :
> > clipka <ano### [at] anonymousorg> wrote:
> >> Am 14.11.2013 19:23, schrieb Samuel Benge:
> >>> "Anthony D. Baye" <Sha### [at] spamnomorehotmailcom> wrote:
> >>>> if you could use the light to drive an actual laser, it might be even more
> >>>> efficient.
> >>>
> >>> Has anyone ever converted direct sunlight into a laser? Or by "laser," do you
> >>> actually just mean "parallel light beam?"
> >>
> >> Lasing media are typically pumped (i.e. supplied with energy to emit
> >> actual laser light) by some kind of conventional light source - so why
> >> not sunlight?
> >
> > Never said it wasn't possible; I was just wondering it anyone had actually made
> > it work :\ Also, why would laser light be better than simply using parallel
> > rays?
>
> Laser has 3 main characteristics (compared to normal light):
>  1. parallel rays (due to the echo chamber, non parallel rays have been
> eliminated) (well, the dispersion cone is very tight)
>  2. single light-wave (at least very narrow spectrum, multiple rays are
> possible but due to pumping it's always an atomic transition of the
> electrons of the pumped material, unless a later frequency divisor is
> used, or a first laser is used to pump a second one)
>  3. synchronised phase of the photons
>
> The destructive power (or heating) is far more efficient due to point 3.
> Point 1 is just an easier way to a better control.
>
> Analogy: lighting a point with normal light is like having a team of
> basketball (or whatever your ball-sport), each with a ball, hitting a
> movable target (let's use your favourite political leader of the wrong
> party) at random time. You get effect but it's less effective than
> having all the balls hitting at the same time. (the purpose being
> obviously to have the target moving away with injuries)

Ah, of course. Makes sense!

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"Anthony D. Baye" <Sha### [at] spamnomorehotmailcom> wrote:
> "Samuel Benge" <stb### [at] hotmailcom> wrote:
> > clipka <ano### [at] anonymousorg> wrote:
> > > Am 14.11.2013 19:23, schrieb Samuel Benge:
> > > > "Anthony D. Baye" <Sha### [at] spamnomorehotmailcom> wrote:
> > > >> if you could use the light to drive an actual laser, it might be even more
> > > >> efficient.
> > > >
> > > > Has anyone ever converted direct sunlight into a laser? Or by "laser," do you
> > > > actually just mean "parallel light beam?"
> > >
> > > Lasing media are typically pumped (i.e. supplied with energy to emit
> > > actual laser light) by some kind of conventional light source - so why
> > > not sunlight?
> >
> > Never said it wasn't possible; I was just wondering it anyone had actually made
> > it work :\ Also, why would laser light be better than simply using parallel
> > rays?
>
> http://www.technologyreview.com/news/408698/solar-powered-laser/
>
> "They work by focusing sunlight onto crystalline materials, such as
> Neodymium-doped Yttrium-Aluminum-Garnet..."
>
> I don't see any problem with modifying the system to use an independent solar
> collector connected with Fibre-optic cables.  There are already collectors like
> that used for providing natural light during the day to indoor spaces, and I've
> read that the light in the cable is so intense that it can start fires if
> connected improperly.

It would be awesome if they (or somebody) eventually did it that way.

I wonder how accurate the sintering process can get? The artifacts on the
finished products look directional somehow, like they were partially caused by
convection.

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