How Can Photons Be Manipulated to Move in the Same Direction?

[Novice4Life]

Is there a low energy way to alter the path of a photon in the direction you want.

From what I've read on here photons pretty much follow the shortest path. Magnetic fields in energy levels that can be reasonably produced do nothing to alter their path. Large gravitational fields distort space-time which means photons aren't bending their still just following the shortest path.

I know some matter can reflect photons so there must be an interaction going on that can be used. Perhaps some kind of crystal or prism with the right attributes.

Ultimately what I want to know is if photons coming from all various directions can be made to move in the same direction.

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[mathman]

I don't know what frequencies you want to work with. However ordinary light can be changed in direction by mirrors and lenses.

 

[Novice4Life]

I don't know what frequencies you want to work with. However ordinary light can be changed in direction by mirrors and lenses.

yes I want ordinary light.

Lenses I'm not sure will do the trick, I know they can focus or diffuse light, but I want to take ambient light and direct it.

For instance if whatever object I used was standing up right, light would be entering at all different angles, but it would only exit at 0 degrees to the horizon.

 

[mathman]

In theory it might be possible with a collection of mini-telescopes, each focused in one direction (as a receiver), covering all directions, and each then transmitting in the desired direction. It looks very impractical.

 

[rawsilk]

Lasers are, practically, the only way of directing light in one direction. Ie photons traveling is parallel. You could try looking at the different types of laser systems. Lasers tend to emplify light however they can also dampen light amplitudes depending what you want.

 

[Bob S]

Ultimately what I want to know is if photons coming from all various directions can be made to move in the same direction.

Liouville's theorem, applied to lenses, states in essence that the product of the beam spot size times the beam divergence is conserved. Look up

http://www.av8n.com/physics/phase-space-thin-lens.htm

Collimator lenses make beams less divergent by expanding the beam size.

Also Google Liouville's theorem phase space.

Bob S

 

[Dr Lots-o'watts]

Here's maybe what you are looking for. Arrange to have your (spherical = all directions) light source at the focus point of an arbitrarily large parabolic mirror:

http://en.wikipedia.org/wiki/Parabolic_reflector

All reflected rays will travel in the same direction.

 

[Bob S]

From

http://en.wikipedia.org/wiki/Parabolic_reflector

"...Conversely, a spherical wave generated by a point source placed in the focus is transformed into a plane wave propagating as a collimated beam along the axis."

I underlined the phrase point source placed at focus, because if it is not a point, then the reflected beam will have a divergence (is not a plane wave).

Bob S

 

[Dr Lots-o'watts]

In practice, the source has to be small compared to the parabola. Points and plane waves are like always, mathematical approximations/simplifications/assumptions.