Polarization of EM wave - does the E vector trace an ellipse w.r.t space as well ?

In summary, the conversation discusses the electric field components of a polarized EM wave and the behavior of the electric field vector at a fixed location of space and time. It is mentioned that when fixing the value of z (direction of propagation), the locus of the electric field vector over time forms an ellipse, known as elliptical polarization. The question arises about the behavior when fixing the value of t (time) and varying z, and it is suggested that it will also result in a change in direction of the electric field vector. The conversation also mentions the possibility of finding an applet to visualize this situation.
  • #1
ask_LXXXVI
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Let us consider the Electric field components of a polarized EM wave .
[PLAIN]http://www.cdeep.iitb.ac.in/nptel/Electrical%20&%20Comm%20Engg/Transmission%20Lines%20and%20EM%20Waves/graphics/CHAP%204__255.png. [Broken]

Now if we fix the value of z (for convenience take z=0) and consider the locus of the Electric field vector over time, we get an ellipse in general. This is what is meant by elliptical polarization. Now this is the temporal aspect. That is - at a fixed location of space , the E vector keeps changing its direction with time (while staying in the plane perpendicular to direction of propagation)

My doubt is what is the behavior when we fix the value of t (let us take t=0 for convenience) and consider the locus of the Electric field vector with respect to the variation in z. Will we get a change in direction of Electric field vector as we change z?

My personal opinion is that it will vary with z also,as the cosine terms in the equation look similar if we suppress either z or t by keeping them fixed . I just want to have a confirmation.
It would be a great help if someone directs me to a website containing an applet which helps in visualizing this particular situation
 
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  • #2


If z is the direction of propagation, then changing z or changing -t is indeed the same.
 
  • #3


0xDEADBEEF said:
If z is the direction of propagation, then changing z or changing -t is indeed the same.

yes z is the direction of propagation .


I guess the spatial variation of the E vector wasn't discussed in the course I took as Polarization deals with the temporal behavior of the fields and not the spatial.
 

1. What is polarization of an electromagnetic wave?

Polarization of an electromagnetic wave refers to the direction in which the electric field vector of the wave oscillates. It describes the orientation of the electric field as the wave travels through space.

2. How does the electric field vector behave in a polarized EM wave?

In a polarized electromagnetic wave, the electric field vector remains constant in both magnitude and direction as the wave propagates through space. This means that the electric field oscillates in a fixed plane perpendicular to the direction of wave propagation.

3. What is the relationship between polarization and the shape of the electric field vector?

The shape of the electric field vector in a polarized EM wave depends on the type of polarization. In linear polarization, the electric field vector traces a straight line. In circular polarization, the electric field vector traces a circle. In elliptical polarization, the electric field vector traces an ellipse.

4. Does the E vector trace an ellipse with respect to space in elliptical polarization?

Yes, in elliptical polarization, the electric field vector traces an ellipse with respect to space. This means that the shape and orientation of the electric field vector changes as the wave travels through space, resulting in an elliptical pattern.

5. How is the polarization of an EM wave determined?

The polarization of an EM wave can be determined by examining the direction and shape of the electric field vector. This can be done using polarizers, which are filters that only allow waves with a specific polarization to pass through. By analyzing the behavior of the wave after passing through the polarizer, the polarization can be determined.

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