What is Polarizer: Definition and 58 Discussions

A polarizer or polariser is an optical filter that lets light waves of a specific polarization pass through while blocking light waves of other polarizations. It can filter a beam of light of undefined or mixed polarization into a beam of well-defined polarization, that is polarized light. The common types of polarizers are linear polarizers and circular polarizers. Polarizers are used in many optical techniques and instruments, and polarizing filters find applications in photography and LCD technology. Polarizers can also be made for other types of electromagnetic waves besides visible light, such as radio waves, microwaves, and X-rays.

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  1. P

    I Switching polarizer and analyzer: the order matters -- why?

    Hey all! I'm a pathologist and just got a polarizer/analyzer pair for my microscope. I decided to play around with them a little before I put them into the microscope to demonstrate the way they block light, and initially I found that no light was blocked no matter how I rotated them relative to...
  2. F

    I What happens when circular polarization meets a diagonal polarizer?

    I'm finding what seems to be conflicting information on this question and could really use some help. It's my understanding that circularly polarized light is composed of two perpendicular linearly polarized components with a 90 degree phase shift between them. When considered individually...
  3. C

    Graphing Power vs Polarizer Angle using Intensity

    The data collected from the experiment is, The first column is the polarizer angle measured in degrees. The second column is recorded intensity measured in lux. The third column is the transmitted intensity measured in lux. This is equal to the recorded lux - ambient lux The fourth column is...
  4. Ian J Miller

    A Did rotating polarizer show violations of Bell's Inequality?

    The Bell inequality requires three conditions, A, B and C that can have two values (pass or fail, say). In the Aspect experiment A defines a plane, B a plane of A rotated by 22.5 degrees, while C is A rotated by 45 degrees. We take joint probabilities, and two are A+.B-, and B+.C-, and from the...
  5. K

    I Determinism in a reversible polarizer experiment

    If light at a known polarization goes through a beam splitting polarizer that changes the light's polarization and then goes through the reverse orientation of that polarizer it will exit with the same polarization that it entered with. See the following picture: If the polarization state...
  6. fluidistic

    I How to "think" of a polarizer in matrix representation?

    From what I remember of my optics course, any element such as a lens (be it thick or thin), can be represented by a matrix. So they are sort of operators, and it is then easy to see how they transform an incident ray, since we can apply the matrix to the electric field vector and see how it gets...
  7. Kaguro

    Circular polarizer followed by a linear analyser

    I think that the intensity of output of circularly polarised light falling on an analyser should not depend upon the axis of analyser. Because it is circularly polarized. It keeps rotating. So, the output should be linearly polarised. The amplitude of E field in the direction of analyser is a...
  8. S

    Question regarding the three polarizer paradox

    Summary: Does the three polarizer paradox work with other materials? Alright, so this is going to sound like a dumb question, but if you were to do the three polarizer experiment but replace the polarizers with a another material, could the different material produce a similar effect to that...
  9. Z

    I Exploring the Effects of a Polarizer on Airy Disks

    When an airy disk is formed, does using a polarizer in front of the pinhole change the shape of the disk?
  10. Marco Masi

    I Double slit with a quarter wave polarizer on one slit

    Suppose a linear polarized light wave front is incident on a double slit. What happens if one places a quarter-wave polarizer in front of only one slit in the double slit experiment? Does one obtain the usual inteference fringes? Or the diffraction pattern only? Else?
  11. B

    I What happens to entanglement inside a polarizer?

    Suppose you prepare two polarization-entangled horizontally polarized photons. Scenario 1: After the first photon passes through a linear polarizer oriented at 45 degrees, it will have later a 50% probability of being measured as horizontally polarized and 50% as vertically polarized. The...
  12. Beth N

    Polarization of Light: Polarizer

    Homework Statement When unpolarized light passes through a polarizer, what happens? A.The light emerges polarized in the polarizer axis direction with about 12the intensity of the incident beam. B.The light emerges polarized perpendicular to the polarizer axis direction with about 12the...
  13. Pushoam

    What happens to waves with different polarizations in a wire grid polarizer?

    It is said that the wave whose polarization is parallel to the wire, gets absorbed by the wire. But, there is empty space between the wires. So, that part of the above - said wave which passes through the empty space will not get absorbed by the wire. So, the transmitted wave must have the wave...
  14. G

    How a TFP (Thin Flim Polarizer) works?

    Hello. I've been really curious about how TFP (Thin Flim Polarizer) works. I've searched TFP information through the Internet which tells that TFP utilizes Brewster's angle. This explains how the P-polarization transmits TFP with 100 % transmission, but I don't know how the S-polarization is...
  15. M

    Camera Lens works as a Polarizer or not?

    I read maxwell says electric field polarizes the dielectrics. Does it mean above effect used at photographic camera lens design to make that lens sometimes works like polarizer filter ? Mustafa Umut Sarac Istanbul
  16. K

    B Why 50% of entangled photons pass through the polarizer?

    Hi. If we have 1 million entangled photons separated from their "entangled partner". We send all those photons (without their "entangled partners") through a polarizer. Each photon has has 50% chance of passing through the polarizer. So 50% of the photons will pass through the polarizer and...
  17. Pattarasak

    When I analyze elliptical polarization using a linear polarizer....

    hello everyone,I want to construct the elliptical polarization in Jones's Matrix form . So, I use the linear polarizer to analyze this polarization. where the Intensity ,which obtain by using the linear polarizer,come from? by integrating overall angle or the other way ?
  18. C

    Condition for circular-wire polarizer to transmit no light

    I want to make a wire grid surface that transmits no light. For that I wanted to use quarter-circular arc wires. My question is what dimensions would I need to apply to the wires, would an arc with radius = wavelength of incident light be sufficient (since then it is the size of a wavelength in...
  19. C

    Is this image of a polarizer misleading?

    On this wire grid polarizer the wires are less wide than one wavelength of the incoming radiation. Is it possible to achieve a specular reflection from a single wire as shown on the image? What about reflection in the plane of length of the wire and the plane perpendicular to it (as shown)? Or...
  20. N

    Linear polarizers: angle between the electric & magnetic fields

    From wikipedia: "An electromagnetic wave such as light consists of a coupled oscillating electric field and magnetic field which are always perpendicular; by convention, the "polarization" of electromagnetic waves refers to the direction of the electric field." A polarizer is an object that...
  21. B

    How to find the orientation of polarization of a polarizer

    If you have a new linear polarizer, how do you find its orientation of polarization? In other words, how do you orient it so it would, let say, polarize light vertically if there is no marking for the 0 degrees angle?
  22. B

    Explore Polarized Light: Tilted Polarizer Effects

    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...
  23. I

    Use of a half wave plate plus polarizer to attenuate lasers?

    The combination of a half-wave plate followed by a polarizer is commonly used as a variable attenuator for polarized lasers. The idea is that the beam enters the half-wave plate, and you rotate the half-wave plate leading to a rotation of the polarization direction of the beam. As the beam is...
  24. I

    Intensity of light passing through 3 polarizers

    Homework Statement Three polarizing disks whose planes are parallel and centered on common axis. The directions of their transmission axes relative to the vertical are respectively: θ1 = 33° clockwise, θ2 = 21° counter-clockwise, and θ3 = 25° clockwise. A beam of light polarized along the...
  25. G

    I Malus' law in the limit of infinitely many polarizers

    Hi. How can I prove $$\lim_{n\to\infty} \cos(\alpha/n)^{2n}=1$$ for all ##\alpha\in\mathbb{R}##? The physical background is Malus' law for perfect linear polarizers, I'd like to show that one can losslessly rotate a linearly polarized wave by any angle by stacking an infinite number of...
  26. TheSodesa

    Two linear polarizers in series

    Homework Statement The optical power of a HeNe -laser is ##P_0 = 5.0mW## and the wavelength ##\lambda = 633nm##. The emitted light is linearly polarized. As the laser beam travels through two in-series -polarizers, the power detected behind the second polarizer ##P_2 = 1mW## . If the first...
  27. S

    Find % Light Through 3 Polarizers

    Homework Statement Polarizers 1 and 3 have their axes of polarization, indicated by the black solid lines, perpendicular to each other. If you try to shine light through only the combination of 1 and 3, you will find that none passes through. However, now we put in another polarizer (number 2...
  28. NihalRi

    Effect of rotating polarizer on intensity of transmitted light

    Homework Statement Plane polarised is incident normally on a polerizer which can rotate in plane perpendicular to light. The intensity of of incident light is 8W[m][/-2] and transmitted intensity is 2W[m][/-2] if polerizer is rotated 90 deg what is the new transmitted intensity Homework...
  29. G

    Do observables for polarizers at different angles commute?

    Hi. We can write a polarised photon as ##\left|\alpha\right\rangle=\cos(\alpha)\left|\updownarrow\right\rangle+\sin(\alpha)\left|\leftrightarrow\right\rangle##. Trigonometry gives us $$\left\langle\alpha | \beta\right\rangle=\cos(\alpha)\cos(\beta)+\sin(\alpha)\sin(\beta)=\cos(\alpha-\beta)$$...
  30. K

    About polarization and polarizer

    Hi all, To me, polarization is the most confusing concepts in optics to me. From the text, it is said that polarization is how the light oriented. A linear polarization means the light is oriented on one direction. But I have few doubts I learn from the book and online materials 1) In most...
  31. O

    Basic LCD Polarizer Viewing Angle

    I'm in need of some help understanding the viewing angle of a basic LCD. I am replicating a product that contains a backlit LCD from a similar product. The original product has an orange display that is clearly viewable at most angles. The similar product has a blue display that has poor...
  32. Sab95

    Regarding Polarizer and viewing sun

    If two polarizers are placed 90 degree rotated to each other, we won't be able to see anything. But when I tried looking directly at sun, which I did only for a second, with that perpendicular pair of polarizers, I was still able to see the sun. Shouldn't the sun disappear too ? Or why is it...
  33. F

    Natural Light and Linear Polarizer

    Hi, In the first place I want to apologize for my bad English. In the second, I have a concept doubt, If I make natural light to go on a linear polarizer of angle 0º, the intensity, or irradiance here, It would be I0/√2 and it's Jones vector would be (1, 0) (as column). What would happen If I...
  34. H

    Light coming straight from an object not affected by Polarizer?

    Sending light through a polarizer changes the intensity of the light depending on the angle the incoming light makes with the parallel axis of the polarizer Ifinal = Iinitial*cos^2(theta) I did not think there were any restrictions on this, but my text says that light directly from an object...
  35. deep838

    Width of a wire grid polarizer

    Why is it that the width of a wire grid polarizer has to be less than the wavelength of the wave which I want to polarize? What would happen if the width was a little bit more?
  36. B

    Angle between polarizer and analyzer

    Homework Statement Consider a polarizer-analyzer arrangement, as shown (here's a link http://i.imgur.com/APZRJ6J.png ) At what angle is the axis of the analyzer to the axis of the polarizer if, after passing through both sheets, the beam intensity is reduced by 67.6 percent? Answer in units of...
  37. i_amitabh

    Flipping a polarizer 180deg. changes polarization

    If you have played around with polarizers you might have noticed that flipping a polarizer by 180o about the vertical axis has the same result as rotating it by 90o about the horizontal axis[i.e. flipping so that the face of the polarizer which was facing away now faces you has the same effect...
  38. S

    Quick question regarding polarizer

    This is not really a homework but I would like to confirm my understanding on the principle of a wire grid polarizer. For the polarizer to filter the polarization of EM wave, waves with e field parallel to the grid will cause the electron to oscillate in the same direction so the wave is...
  39. I

    What could cause a polarizer to not block 100% light?

    i have a cheap polarizing shade i bought from walmart. i aligned my polarizing shades with the polarized light coming from my laptop, however not all the light was blocked. just to be extra sure that it wasn't my lcd that was being weird, i rotated a laser beam through my polarizing shades, and...
  40. S

    Photon behavior after the polarizer

    Let's say we pass a photon through a 0 degree polarizer. the photon is now oriented at 0 degrees, meaning it will pass through subsequent polarizeres oriented at 0 degrees. (note - Not all photons will pass through the 0 degree polarizer, roughly 50% will pass through. we are talking about...
  41. genxium

    [Lab]difference between diffraction grating and linear polarizer ?

    [Lab]difference between "diffraction grating" and "linear polarizer" ? I'm recently looking for optical devices to do some experiments at home, like diffraction and polarization, but when I turn to Amazon for the goods, I found that both the sheets I want are marked: 500 lines/mm -- diffraction...
  42. B

    Solving for Intensity of Light Through a Polarizer

    Homework Statement Vertically polarized light with an intensity of 0.65 W/m2 passes through a polarizer whose transmission axis is at an angle of 30.0° with the vertical. What is the intensity of the transmitted light? I0 = 0.65 W/m2 theta = 30.0 degreesHomework Equations...
  43. C

    Intensity of Light With a Given Power of Through a Polarizer

    1. Homework Statement A 200 mW horizontally polarized laser beam passes through a polarizing filter whose axis is 25 degrees from vertical. What is the power of the laser beam as it emerges from the filter? P=mW 2. Homework Equations I0cos2(theta) I≈E0cos(theta) I=E0cos2(theta)...
  44. K

    Unknown Light Source Through Polarizer

    I recently had a homework problem that asked the following. Can someone please explain to me how in the world this can be true?! It makes no sense to me that you can get an intensity that is equal to when light is passed through a vertical transmission axis and a horizontal transmission axis...
  45. D

    Reflected light from a polarizer

    Hi Folks, I have a general question. What happens to unpolarized light once it's reflected from a polarizer? My best guess is that it's polarized with opposite parity relative to the transmitted light with intensity varying as a function of angle of incidence. I think my answer applies...
  46. N

    Passing elliptically polarized light through a linear polarizer

    Hi Here (https://www.physicsforums.com/showthread.php?t=119847) it is mentioned that the intensity when passing elliptically polarized light through a linear polarizer will vary when turning the polarizer. Doesn't this only hold assuming the two components of the light are not equal? I mean...
  47. C

    QWP Polarizer Question

    Homework Statement http://i.imgur.com/awJgh.png Homework Equations The Attempt at a Solution Is just because lights out of QWP become unpolarized so 0.5*0.5 = 0.25? Thanks!
  48. C

    Light through a polarizer

    Homework Statement Unpolarized light passes through a polarizer oriented at 33 degrees from the horizontal axis. 1) At what angle (relative to the horizontal axis) would you place a polarizer so that no light passes through it? 2) At what angle (relative to the horizontal axis) would you...
  49. J

    Rotating Polarizer 90 Degrees With Only 10 Percent Loss

    Homework Statement Describe how to rotate the plane of polarization of a plane-polarized beam of light by $90^\circ$ and produce only a 10 percent loss in intensity using "perfect" polarizers. The solution says to use 24 polarizers, with each at an angle of $3.75^\circ$ with the next...
  50. N

    Modeling a wire grid polarizer.

    Hello, I keep myself busy by trying to model/predict standing waves in the optical path of a heterodyne spectrometer we built in our lab. We split and combine the local oscillator and the sky (it's for astronomy) with a beam splitter. Our beam splitters are wire grid polarizers. The...