Does a Single Metal Stripe Reflect Polarized Light at the Angle of Incidence?

In summary: So if you had a metal sheet 1nm thick and 1mm wide, it would scatter light but would not be reflective. If radiation falls on a metal rod just half a wavelength long, it excites current in the rod (except for the case where the radiation is exactly 90 deg polarised to the rod). The rod then radiates the energy into a plane of polarisation lying along its length.In this way we can see that polarisation can be rotated, because an incident polarisation will have a component acting along the rod which will induce current. The radiation pattern of the rod is that of a half wave dipole. If many rods are used then the pattern is that of a broadside array.
  • #1
Christofer Br
51
0
I know that only light with polarization in the plane of the "stripe" gets reflected.
What i need to know is if a single metal stripe could reflect such polarised light at ONLY the angle equal to the angle of incidence or do only a whole array of stripes produce specular reflections?
Sources are welcome
Thank you

(PLEASE keep the "duplicate" button in the holster, I've looked the whole forum and couldn't find this question adequatly answered, and i really need to know)
 
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  • #2
It depends how wide the stripe was. A metal polariser for microwaves will work well but the stripes are only a couple of mm wide and spaced by less than a half wavelength. How would you achieve that, scaled down for a wavelength of 600mn?
Also, a single stripe will act as a scatterer and any re-emitted waves will be spread around in an arc of up to 360°. You need a fair width (many wavelengths) to ensure you get a specular reflection (like a beam reflected a mirror)
What do you already know about polarisers?
 
  • #3
Christofer Br said:
I know that only light with polarization in the plane of the "stripe" gets reflected.
What i need to know is if a single metal stripe could reflect such polarised light at ONLY the angle equal to the angle of incidence or do only a whole array of stripes produce specular reflections?
Sources are welcome
Thank you

(PLEASE keep the "duplicate" button in the holster, I've looked the whole forum and couldn't find this question adequatly answered, and i really need to know)
Here is a source:http://chriswalkertechblog.blogspot.com/2012/08/glare-and-polarized-light-in-machine.html
The polarizing effects you posted about do not occur when using a metallic reflecting surface.
 
  • #4
sophiecentaur said:
It depends how wide the stripe was. A metal polariser for microwaves will work well but the stripes are only a couple of mm wide and spaced by less than a half wavelength. How would you achieve that, scaled down for a wavelength of 600mn?
Also, a single stripe will act as a scatterer and any re-emitted waves will be spread around in an arc of up to 360°. You need a fair width (many wavelengths) to ensure you get a specular reflection (like a beam reflected a mirror)
What do you already know about polarisers?
This question isn't really about polarizers;

i was pretty sure to achieve a specular reflection i only need the electrons to have enough room to fully oscillate in the plane of the electric field. Can you confirm that even with the width of one wavelength i would still not get a specular reflection? What about a case where light is incident at angle only in the plane of the length of the wire - since in this plane there are many wavelengths worth of conductor would the reflection be specular?
 
  • #5
.Scott said:
Here is a source:http://chriswalkertechblog.blogspot.com/2012/08/glare-and-polarized-light-in-machine.html
The polarizing effects you posted about do not occur when using a metallic reflecting surface.
Sincerely i think the content of the link is unrelated; it treats essentially about how metallic objects preserve the polarisation of light by shifiting the phase of all incident light by pi/2 unlike other surfaces. It is the object of this question to determine if a single stripe from a polarizer reflects specularly as does an array of them - the whole polarizer.
 
  • #6
Christofer Br said:
i only need the electrons to have enough room to fully oscillate
I wonder what your rationale was for that comment. How far do you think an electron (treated classically), oscillating at nearly 1000THz, could be displaced?
 
  • #7
Christofer Br said:
I know that only light with polarization in the plane of the "stripe" gets reflected.
What i need to know is if a single metal stripe could reflect such polarised light at ONLY the angle equal to the angle of incidence or do only a whole array of stripes produce specular reflections?
Sources are welcome
Thank you

(PLEASE keep the "duplicate" button in the holster, I've looked the whole forum and couldn't find this question adequatly answered, and i really need to know)
If radiation falls on a metal rod just half a wavelength long, it excites current in the rod (except for the case where the radiation is exactly 90 deg polarised to the rod). The rod then radiates the energy into a plane of polarisation lying along its length.
In this way we can see that polarisation can be rotated, because an incident polarisation will have a component acting along the rod which will induce current.
The radiation pattern of the rod is that of a half wave dipole. If many rods are used then the pattern is that of a broadside array.
 
  • #8
sophiecentaur said:
I wonder what your rationale was for that comment. How far do you think an electron (treated classically), oscillating at nearly 1000THz, could be displaced?
I was thinking about this particular case - usually authors state the in order to achieve geometrical scattering you need a flat surface larger than the wavelength (not specifying if it starts at the wavelength or some multiple of it). My logic was that it only really needs to be larger in the plane of the electric field since polarizers reflect the way they do and I always seen them reflect specularly on diagrams - therefore it appeared to be geometric scattering.
So, what about the previously mentioned case with reflection along the length of the stripe?
 
  • #9
Christofer Br said:
I was thinking about this particular case - usually authors state the in order to achieve geometrical scattering you need a flat surface larger than the wavelength (not specifying if it starts at the wavelength or some multiple of it). My logic was that it only really needs to be larger in the plane of the electric field since polarizers reflect the way they do and I always seen them reflect specularly on diagrams - therefore it appeared to be geometric scattering.
So, what about the previously mentioned case with reflection along the length of the stripe?
If we have one stripe and the polarisation of the incident wave is along the stripe (in the same plane) then I believe the following occurs:-
1) If the stripe is much less than half a wavelength long. Very little radiation.
2) If the stripe is half a wavelength long. Radiation normal to the stripe, with a dipole pattern.
3) If the stripe is long. An oblique incident wave will induce currents in the stripe which are forced everywhere to be in phase with the wavefront as it hits the stripe. This will create re-radiation where angle of incidence = angle of reflection. However, if the stripe is less than half a wavelength wide, the re-radiation will be in a cone surrounding the stripe. The width of the conical beam is decided by the length of the stripe.
 

Related to Does a Single Metal Stripe Reflect Polarized Light at the Angle of Incidence?

1. How do polarizers reflect light?

Polarizers are optical filters that are specially designed to only allow light waves to pass through in a specific orientation. When unpolarized light enters a polarizer, it is filtered and only the light waves with the same orientation as the polarizer's axis are transmitted, while the others are absorbed or reflected.

2. Why do polarizers reflect light?

Polarizers reflect light because they are made up of long-chain molecules that are aligned in a specific direction. These molecules act as a mesh that only allows light waves to pass through in a certain orientation, while blocking or reflecting the light waves with a different orientation.

3. How do polarizers change the direction of reflected light?

Polarizers do not change the direction of reflected light. Instead, they selectively absorb light waves with a specific orientation, resulting in the transmitted light having a different direction than the original light. This is known as polarization and is used to reduce glare and improve visibility in certain situations.

4. What types of light are reflected by polarizers?

Polarizers reflect all types of light, but only in specific orientations. For example, a polarizer with a vertical axis will only transmit vertical light waves and reflect horizontal light waves. This is why polarizers are commonly used in sunglasses and camera filters to reduce glare from horizontal surfaces like water or snow.

5. Can polarizers reflect all colors of light?

Yes, polarizers can reflect all colors of light, but the amount of reflection may vary depending on the color. For example, polarizers are most effective at blocking or reflecting light that is perpendicular to their axis, so colors that are closer to that orientation may be more strongly reflected. However, polarizers can also be designed to reflect specific colors more than others, making them useful for a variety of applications.

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