User:Dave3457/Sandbox/Handedness

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Handedness


It is my hope that different people will give their views on this subject and that at least Wikipedia editors can come to some sort of consensus.

The below is what I have gathered. It would seem with optics and physics that when considering the clockwise or counter-clockwise temporal rotation of the field, you take the point of view of the receiver and you face the opposite direction of travel. The defined right/left handedness can be determined by considering the spacial rotation of a helix. The "forward" direction of the helix matches the direction of your right/left thumb. Note: That it does not matter in what direction you point your thumb. To determine the handedness using the temporal rotation, you point your thumb in the opposite direction of travel.

Their definition of handedness matches the Federal Standard 1037C position. http://www.its.bldrdoc.gov/fs-1037/dir-007/_0972.htm

Circular polarization: In electromagnetic wave propagation, polarization such that the tip of the electric field vector describes a helix.

Note 4: Circular polarization may be referred to as "right-hand" or "left-hand," depending on whether the helix describes the thread of a right-hand or left-hand screw, respectively. Note that they don't define clockwise and counter-clockwise.

In the text book...

HANDBOOK OPTICS Volume I,Devices, Measurements and Properties,Michael Bass

It says in a footnote on page 272 Right-circularly polarized light is defined as a clockwise rotation of the electric vector when the observer is looking against the direction the wave is traveling.

This matches all the above statements and the image.

With regards to Engineering.

You determine clockwise and counter-clockwise polarization by considering the temporal rotation of the field from the point of view of the transmitter. You determine handedness by pointing your thumb in the direction of travel and curling your fingers in the direction of the temporal rotation of the field. You do not define handedness using the spacial rotation of a helix.

In the book

Electromagnetic Waves & Antennas – S. J. Orfanidis.pdf He talks in detail. Note that when he uses the terms 'clockwise" and "counter-clockwise" he is not refering to whether the light is "clockwise" or "counter-clockwise" polarized. He is in fact referring to the direction of rotation looking down the z-axis towards the origin. Note also that "forward moving" is in the positive z direction. Page 36... Ex(z, t) = Acos(ωt − kz + φa) Ey(z, t) = Bcos(ωt − kz + φb)

To determine the polarization of the wave, we consider the time-dependence of these fields at some fixed Point along the z-axis…

Pg 37...

Ex(t) = Acosωt Ey(t) = Acos(ωt + π/2)= −Asinωt

The tip of the electric field vector rotates clockwise on the xy-plane. Since the wave is moving forward, this will represent left-circular polarization. Forward moving is in the positive z direction

To decide whether this represents right or left circular polarization, we use the IEEE convention which is as follows.

Curl the fingers of your left and right hands into a fist and point both thumbs towards the direction of propagation. If the fingers of your right (left) hand are curling in the direction of rotation of the electric field, then the polarization is right (left) polarized.†

Thus, in the present example, because we had a forward-moving field and the field is turning counterclockwise, the polarization will be right-circular.

The foot note reads

†Most engineering texts use the IEEE convention and most physics texts, the opposite convention.

The opposite convention seems to be the Federal Standard