Mark L. Fergerson wrote:
From what you're saying, I am guessing that electronics are not
necessarily needed to power photonics *but* electricity is the most
*practical* source of energy for photonic components. Am I at least on
the right track? If not, please correct me.
When most of us see the word "photonics" we think LEDs/lasers and
photocells/photoresistors/phototransistors, meaning devices that
translate electronic signals into light impulses and back but not often
things that do something interesting to the signal stream like modulate
it while it's in photon form. Generally speaking the base technology is
electronics and the photonic bits are there to overcome some of the
limitations of electronics like enough bandwidth to get from one signal
processor to another and noise immunity.
I suppose that at some point
most of the things we do with electronics (signal processing-wise) will
be done with photons, and the electronic part will be limited to the
power supply for the LEDs/lasers etc.
Is there any *practical* source of power other than electricity that
could be used to energize these LEDs and lasers?
Lasers need to be "pumped" in order for them to emit light. This
means that the electrons in the lasing medium's atoms have to be shoved
up to a higher-than-normal energy level and allowed to fall back on
command, as it were. When they fall back they emit photons with energy
equal to the difference between the high and low levels. A given photon
will stimulate an "unfallen" electron in another atom to also fall, and
the resulting photon from the second atom is "in step" with the first
photon; the process repeats until all the electrons have given up their
photons (it's actually somewhat more complicated than that, but I'll
assume you know how to use Google).
There are only so many ways to manipulate electrons, and it depends
what you mean by "practical". Chemical lasers are well-known but hard to
control with the delicacy electrically-pumped lasers can achieve and are
somewhat awkward support-machinery-speaking. Lasers can be
optically-pumped as well (ruby and doped-glass lasers frinst), but that
just pushes the power source question one step back. There are also
free-electron lasers but they are basically electron tubes with magnet
arrays the beam passes over.
What are you getting at, and what do you think is "impractical" with
the way we do it now?
Mark L. Fergerson