The Power of Circulating Light: Optical Force Explained

[gonegahgah]

http://www.theengineer.co.uk/sectors/electronics/news/device-uses-light-to-rapidly-turn-a-switch-on-and-off/1014158.article

"The researchers’ new device has two optical waveguides, each carrying an optical signal. Placed between the waveguides is an optical resonator. In the optical resonator, light can circulate hundreds of times, gaining intensity.
Using this resonance effect, the optical signal in the first waveguide is enhanced in the resonator and generates a very strong optical force on the second waveguide."

Can someone help me please? What is an optical force in the context of this article?

 

[sophiecentaur]

"Can someone help me please? What is an optical force in the context of this article?"

I think they are referring to what used to be called Light or Radiation Pressure. When light hits an object there is a transfer of Momentum.This can with be explained in terms of the Momentum of photons or there is a perfectly good explanation, using Classical Electromagnetic theory.

 

[BrandonP]

I can help -- give me a minute to read the article...

 

[BrandonP]

Ok -- I read it briefly...
Just think of a transistor. Transistors do this with electrons.
Apparently this one uses light instead of electricity -- photons.
Interesting -- in quantum physics experiments photons and electrons can be used interchangeably usually.

I guess this light-transistor does the same thing. but faster.

 

[BrandonP]

If it was electrons we would call that Voltage.

So I guess for the light force they could give it any name they want.

 

[BrandonP]

What is an optical force in the context of this article?

In the context of the article "optical force" would be analogous to "electrical energy"

Or, the amount of light something gives off aka "luminescence"

 

[gonegahgah]

Thanks Brandon. Transistors certainly switch but in a solid state way which is cool. In the article they are referring to it being like a relay. ie. "’This device is similar to electromechanical relays but operates completely with light". And, "nanoscale light conduits can be used to generate a strong enough optical force with light to mechanically move the optical waveguide."

The "electrical energy" in a normal relay creates a magnetic force to physically move a metal spring arm to make or release contact.
The "waveguide" in the article isn't metallic is it? If it's not magnetic force then I'm wondering what this "optical force" is?
Being guided through "nanoscale light conduits" I'm not sure that any light is being given off?

 

[Doc Al]

I think they are referring to what used to be called Light or Radiation Pressure. When light hits an object there is a transfer of Momentum.This can with be explained in terms of the Momentum of photons or there is a perfectly good explanation, using Classical Electromagnetic theory.

I believe you are correct.

Here's a preprint of the actual article, if anyone wants to wade through it Optomechanical photon shuttling between photonic cavities

 

[Andy Resnick]

Interesting- the OP paper seems to simply refer to radiation pressure, not photon-phonon coupling. This review:

http://arxiv.org/pdf/1303.0733v1.pdf

may be of interest as well.