Optical diode, a one way light guide

One way optical propagation is very old news indeed. Google "Faraday isolator".

Cheers

Phil Hobbs

On a sunny day (Fri, 05 Aug 2011 08:47:51 -0400) it happened Phil Hobbs wrote in :

Yes, and I was thinking they have those one way mirrors... But these guys did it on silicon, with normal processes, and it can be integrated.

Lots of things are 're-invented', I today did see somebody invent the mixer.... The mix photons down and maintain their wave shape. AM -- mixer- now photon is a wave (with sideband spectrum, or enveloppe) to them :-)

"Publish or Perish", and a couple of thousand journals that need to be fed.

John

Apparently polar bears are quite hungry these days

So what?

Thanks, Rich

"One way mirrors", as used in TV cop shows, don't have differential reflection; they are just, like, 95% mirrors or some such. A true one-way mirror is forbidden by conservation of energy.

John

Not according to Quantum Electrodynamics by Richard P. Feynman in his book "QED The Strange Theory of Light and Matter" by Princeton Publishing.

Excellent reading.

John S

What page did he say that on?

If you had an isolated chamber and separated it into two sections with a one-way mirror, one side would get hot and the other side would get cold. You could run a heat pump from that and get free energy forever.

John

You can do it with polarization tricks if (a) you start with polarized light, or (b) you don't mind a 50% loss, or (c) you can live with a two-path optical system.

A half-silvered mirror has a there-and-back loss of at least 75% (any absorption in the mirror will make it worse).

Cheers

Phil Hobbs

Have you told Obama?

The laws of thermodynamics are very accurate in the thermodynamic limit (i.e. systems large enough that fluctuations due to counting statistics can be ignored). Energy conservation seems to be accurate at all length scales smaller than the size of the universe, but interestingly there's a nonconservation mechanism due to the large-scale expansion of the universe: an object with some peculiar velocity gradually finds itself surrounded by objects moving at nearly the same speed it is, i.e. its kinetic energy goes to zero with time.

Cheers

Phil Hobbs

So does the volumetric energy density of the universe drop as the universe expands, to keep the total energy constant?

John

It would depend on how you define volume, among other things. Developments in cosmology over the last 30 years or so have really underscored the fact that you can't automatically generalize from lab length scales to cosmic ones.

Gotta go pack.

Cheers

Phil Hobbs

That was his point, i.e. a true one-way mirror violates conservation of energy,

integrated.

Well, GURR to you too..I must be a Polar Baer because I am white.. And BTW, i a am alive and kicking.

You did not think that one out! May i help with the question: where would that energy come from?

On a sunny day (Fri, 05 Aug 2011 18:59:43 -0700) it happened John Larkin wrote in :

Yes, and no, if the light one way is converted to heat, no energy law is violated.

On a sunny day (Fri, 05 Aug 2011 22:09:54 -0500) it happened " snipped-for-privacy@att.bizzzzzzzzzzzz" wrote in :

LOL :-)

On a sunny day (Fri, 05 Aug 2011 14:35:32 -0700) it happened Rich Grise wrote in :

It is spelled Watt.