# Explore Polarized Light: Tilted Polarizer Effects

• Boomzxc
In summary: It is all more complicated that at first sight and what pictures of waves on ropes and slots in metal sheets would...In summary,-What would happen, or what would be the outcome/result if the first or second Polaroid in a setup shown in the above two images, is *tilted* forward or backward?-Secondary question:-How does the cross section of a Polariser looks like; how does a Polariser polarise light?-Is a Polariser made up of many sheets of polaroids?-The answer to your first question is complicated, the specifics depend entirely on the surface (which is why normal incidence is used in class). For what it
Boomzxc
https://www.dropbox.com/s/t5lv4nlunn35ok8/phy1.PNG?dl=0
https://www.dropbox.com/s/ktc9pj7qmqhejrv/phy2.PNG?dl=0
https://www.dropbox.com/s/qbjz1p1gokvsgj2/Capture3.PNG?dl=0

I googled "polarizer film diagram" and "malu's law" and "polarizer physics" to obtain the pictures in this thread.
I understand we usually study polarised light phenomena by rotating polaroids.

I am curious about this : What would happen, or what would be the outcome/result if the first or second Polaroid in a setup shown in the above two images, is *tilted* forward or backwards? as in, the Polaroid is firm on it's base, just that it is *tilted* either forward or backwards. What would be the outcome when polarised light, and unpolarised light pass through the Polaroid?
Will light still pass through, or be polarised, through tilted Polaroid(s)?
Or is it just that Intensity will be affected, or Polarised light will not emerge straight, and rather at an angle?
Will light still be polarised the same way and angle as a untilted Polaroid(such as the base perpendicular to the table, untilted), just that less light is passed through?

Sorry I do not have a lab or the required gear to experiment this myself.Secondary question :
How does the cross section of a Polariser looks like; how does a Polariser polarise light?
Isn't light polarised by passing through tiny vertical slits? Why is light not polarised through the tiny slits of a diffraction grating?
Is a Polariser made up of many sheets of polaroids?

A very large and warm Thank-you to all that have replied

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Boomzxc said:
What would happen, or what would be the outcome/result if the first or second Polaroid in a setup shown in the above two images, is *tilted* forward or backwards? <snip>
Secondary question :
How does the cross section of a Polariser looks like; how does a Polariser polarise light?
Isn't light polarised by passing through tiny vertical slits? Why is light not polarised through the tiny slits of a diffraction grating?
Is a Polariser made up of many sheets of polaroids?

The answer to your first question is complicated, the specifics depend entirely on the surface (which is why normal incidence is used in class). For what it's worth, here's a comprehensive report on the subject:

https://repository.tudelft.nl/islan...92-4960-b0fe-5ccbc95da562?collection=research

(you want chapter 3).

As for the second question, that isn't a good analogy. If anything, the polarization component *perpendicular* to the slits passes through, while the polarization component parallel is blocked. To be sure, far-infrared polarizers are indeed parallel wires. However, polarizers can be constructed from a variety of materials, not just sheets of Polaroid: certain prism geometries separate orthogonal polarizations.

Boomzxc
Andy Resnick said:
As for the second question, that isn't a good analogy.
If a polariser consisted of narrow slits then a 'perfect' polariser would need to have infinitely thin slits - which would admit no light. In fact, the energy from an unpolarised source through a perfect polariser only drops by half.

sophiecentaur said:
If a polariser consisted of narrow slits then a 'perfect' polariser would need to have infinitely thin slits - which would admit no light. In fact, the energy from an unpolarised source through a perfect polariser only drops by half.

In the case of FIR polarizers, the wire width and spacing are subwavelength- not a big deal when the wavelength is 100 um.

Andy Resnick said:
In the case of FIR polarizers, the wire width and spacing are subwavelength- not a big deal when the wavelength is 100 um.
I am a tad confused here. A good microwave polariser can be made in a similar way with a grid of parallel wires (spaced by perhaps a tenth of a wavelength, IIRC). In that case, currents that are induced in the wires that will reflect the wave components that are parallel with the wires and the spaces in between the wires have no induced currents so the wave component passes through. So the transmitted polarisation is normal to the direction of the slots. Is the action of a FIR polariser different from that?

sophiecentaur said:
Is the action of a FIR polariser different from that?

nope- exactly the same. Did I say otherwise?

Andy Resnick said:
nope- exactly the same. Did I say otherwise?
No you didn't say otherwise. It's just that the 'slots' are not in the same orientation as the resulting polarisation. That could be regarded as counter-intuitive and certainly doesn't tie in with the over simplified explanations that we see in textbooks. Also, I thought polaroids worked on absorption of the other polarisation and that is not how an RF polariser works.
It is all more complicated that at first sight and what pictures of waves on ropes and slots in metal sheets would imply.

## 1. What is polarized light?

Polarized light is a type of light that has its waves aligned in a specific direction. This means that the light waves are oscillating in a single plane rather than in all directions. This results in a light that appears to be dimmer and has a specific direction of vibration.

## 2. How is polarized light created?

Polarized light is created by passing unpolarized light through a polarizing filter. The filter contains microscopic slits or molecules that only allow light waves to pass through in a specific direction, thus polarizing the light. The most common polarizing filters are made of special materials like Polaroid sheets or crystals.

## 3. What is the effect of a tilted polarizer on polarized light?

When a polarizer is tilted at an angle, it reduces the amount of polarized light that can pass through it. This is because the polarizer is now blocking some of the light waves that were previously able to pass through when it was perpendicular to the light source. This results in a decrease in the intensity of the polarized light.

## 4. How does the angle of the polarizer affect the intensity of polarized light?

The intensity of polarized light is directly proportional to the angle of the polarizer. This means that the more the polarizer is tilted, the less intense the polarized light will be. When the polarizer is perpendicular to the light source, it will allow the maximum amount of polarized light to pass through. As the angle increases, the intensity decreases.

## 5. What are the practical applications of polarized light and tilted polarizers?

Polarized light and tilted polarizers have various applications in everyday life. They are used in sunglasses to reduce glare and improve visibility. They are also used in photography to enhance colors and reduce reflections. In science, polarized light is used to study the properties of materials and in medical imaging techniques like polarized light microscopy.

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