mes (10/23/82)
This is a call to interested and/or knowledgeable peo-
ple who might have some ideas about the possible uses of
photoreversible pigments in logical devices such as memory.
(If that looks complicated, see the explanation). Comments,
information, and other assistance regarding this pipe-dream
will be appreciated.
Explanation
In plants, evolution has already produced a pigment
capable of reverting from one absorption form to another in
what are known as phytochromes. These compounds are essen-
tially proteins with an attached light-absorbing chromato-
phore portion. Red light causes the phytochrome (Pr) to
convert to the Pfr form, which is capable of reconverting to
the Pr upon absorbing far-red light.
There are several problems with using this as a logical
device, (Aside from the obvious engineering difficulties)
however:
1) It is impossible to avoid a racemic mixture.
2) Although Pr to Pfr takes about < 10E-12 seconds,
Pfr to Pr takes more than 1 second.
3) Phytochrome is unstable,
and will eventually revert to one form.
Therefore, another related (possibly) compound must be
sought after. What nature took millions of years to do, man
should be able to accomplish in a few.
There are some possibilities that photon circuitry
would be able to explore or exploit, given the proper logi-
cal devices, photomultipliers, pathways, etc.:
1) Propogation speed approaching c (in vacuum) than electrons
in current circuitry, allowing more i.p.s.
2) New twists in
a) pattern recognition
b) holographic memory
c) signal (dx) processing
d) image processing
3) Simultaneous pathway use by polarized signals,
regardless of direction.
4) ?
It should be understood that the two contributors of
this article are not giants in the fields of physics or
organic chemistry; nor do they yet have the time necessary
to explore this subject until certain degree (M.S. Biology
and M.S. Computer Science) obligations are met. History has
shown that fresh ideas produced at the right time and place
can go far, so, have fun.