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I have a “circular” polarizer for photographic work but it is also a linear polarizer. A polarizer labeled “circular” may not be circular only so that is another thing to watch for. Circular polarizers should be perfectly clear since they don’t block light the way linear polarizers do. They simply give the light a “twist” as it passes through.
https://en.wikipedia.org/wiki/Polarizing_filter_(photography)#TypesCircular polarizing photographic filters consist of a linear polarizer on the front, with a quarter-wave plate on the back. The quarter-wave plate converts the selected polarization to circularly polarized light inside the camera. This works with all types of cameras, because mirrors and beam-splitters split circularly polarized light the same way they split unpolarized light.Linear polarizing filters can be easily distinguished from circular polarizers. In linear polarizing filters, the polarizing effect works (rotate to see differences) regardless of which side of the filter the scene is viewed from. In "circular" polarizing filters, the polarizing effect works when the scene is viewed from the male threaded (back) side of the filter, but does not work when looking through it backwards.
https://www.apioptics.com/about-api/api-blog/api-news/how-circular-polarization-works/A circular polarizer is made up of two components: a linear polarized filter and a quarter-wave plate. The input light going into the linear polarizer filter is known as being randomly polarized (I prefer that term over “unpolarized light” because all light is polarized). The light exiting the linear polarizer filter is now considered linearly polarized light because the plane of polarization of the output light is in one direction instead of being random (or unpolarized).The linearly polarized light then passes through the quarter-wave plate. Here is the critical and tricky part: the polarization axis is a vector between the electrical fields (Ex and Ey respectively).The quarter-wave plate has what is called a Fast Axis and a Slow Axis. Note that the “Quarter Wave” designation denotes how much the Slow Axis will retard one of the electrical fields as it passes through the wave plate. To create true circularly polarized light (as opposed to elliptically polarized light), the polarizing axis must be at 45º to the fast and slow axis. Thus the relative 45º polarizer axis allows the electromagnetic fields to be parallel to the fast and slow axis of the wave plate. With all that lined up, the polarized light then exits the quarter-wave plate, with either the Ex or Ey fields shifted by a quarter of a wave.//www.youtube.com/watch?v=Fu-aYnRkUgg
You can use 3D glasses for circular polarization filter. One side would be clock-wise, and the other would be counter-clock-wise.Quote
. Circular polarizers should be perfectly clear since they don’t block light the way linear polarizers do. They simply give the light a “twist” as it passes through.
Fresnel and Arago explained that linearly polarized light interferes so rapidly and randomly that the regular pattern of diffraction is lost but their explanation does not extend to circularly polarized light.
3D glasses are like ordinary linearly polarized sunglasses with clear cellophane tape at orthogonal angles placed over the lenses to make them both linearly and circularly polarized. That is why I use cellophane tape alone as a polarizer.
Quote from: bamgstrom on 29/10/2021 07:54:36. Circular polarizers should be perfectly clear since they don’t block light the way linear polarizers do. They simply give the light a “twist” as it passes through.That's not how it works.
Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circular birefringence and circular dichroism are the manifestations of optical activity.
Does this help?https://aapt.scitation.org/doi/10.1119/1.16432
ABSTRACTCoherent light in the two arms of a Michelson interferometer are made circularly polarized but with opposite rotations. When the two beams recombine, the light is linearly polarized but the direction of polarization changes depending on the phase between the two beams. When a linear polarizer is used on the output and rotated, the observed interference fringe pattern shifts. If the field of view contains circular fringes, the continuous rotation of the polarizer in one direction makes the circles continuously expand or contract.
Quote from: bamgstrom on 06/11/2021 20:00:28Fresnel and Arago explained that linearly polarized light interferes so rapidly and randomly that the regular pattern of diffraction is lost but their explanation does not extend to circularly polarized light.Where did you find the source of that information? It looks like you've been misled, or misunderstood things they tried to explain.
Quotes in my reply#2 above has explained how circular polarizers work. Which part of it do you think unclear or inaccurate?
Quote from: hamdani yusuf on 07/11/2021 01:48:50Quote from: bamgstrom on 06/11/2021 20:00:28Fresnel and Arago explained that linearly polarized light interferes so rapidly and randomly that the regular pattern of diffraction is lost but their explanation does not extend to circularly polarized light.Where did you find the source of that information? It looks like you've been misled, or misunderstood things they tried to explain.My information comes from the original Fresnel-Arago article describing their three laws of polarization. Wikipedia also has an easy-to-find reference under “Fresnel-Arago Laws. ” Let me know if your interpretation is different from mine.
The laws are as follows:Two orthogonal, coherent linearly polarized waves cannot interfere.Two parallel coherent linearly polarized waves will interfere in the same way as natural light.The two constituent orthogonal linearly polarized states of natural light cannot interfere to form a readily observable interference pattern, even if rotated into alignment (because they are incoherent).https://en.wikipedia.org/wiki/Fresnel%E2%80%93Arago_laws
On the other hand, I find that circularly polarized light (not elliptically polarized) does interfere.
//www.youtube.com/watch?v=0ukdaIComZc [nofollow]Just in case you haven't seen the real life experiment yet.
Do you have any information about what he uses as a “particle detector” and how it works?
https://en.wikipedia.org/wiki/Photon_countingPhoton counting is a technique in which individual photons are counted using a single-photon detector (SPD). A single-photon detector emits a pulse of signal for each detected photon, in contrast to a normal photodetector, which generates an analog signal proportional to the photon flux. The number of pulses (but not their amplitude) is counted, giving an integer number of photons detected per measurement interval. The counting efficiency is determined by the quantum efficiency and the system's electronic losses.Many photodetectors can be configured to detect individual photons, each with relative advantages and disadvantages. Common types include photomultipliers, geiger counters, single-photon avalanche diodes, superconducting nanowire single-photon detectors, transition edge sensors, and scintillation counters. Charge-coupled devices can be used.AdvantagesPhoton counting eliminates gain noise, where the proportionality constant between analog signal out and number of photons varies randomly. Thus, the excess noise factor of a photon-counting detector is unity, and the achievable signal-to-noise ratio for a fixed number of photons is generally higher than the same detector without photon counting.Photon counting can improve temporal resolution. In a conventional detector, multiple arriving photons generate overlapping impulse responses, limiting temporal resolution to approximately the fall time of the detector. However, if it is known that a single photon was detected, the center of the impulse response can be evaluated to precisely determine its arrival time. Using time-correlated single-photon counting (TCSPC), temporal resolution of less than 25 ps has been demonstrated using detectors with a fall time more than 20 times greater.DisadvantagesSingle-photon detectors are typically limited to detecting one photon at a time and may require time between detection events to reset. Photons that arrive during this interval may not be detected. Therefore, the maximum light intensity that can be accurately measured is typically low. Images/measurements composed of small numbers of photons intrinsically have a low signal-to-noise ratio due to shot noise caused by the randomly varying numbers of emitted photons. This effect is less pronounced in conventional detectors that can concurrently detect large numbers of photons, mitigating shot noise. Therefore the signal-to-noise ratio with photon counting is typically much lower than conventional detection, and obtaining usable images may require long acquisition times.
Can Anyone provide a Simplistic four lines explanation of what the " Quantum Eraser Experiment " is?ps - i am tired of using Utube!
The Quantum Eraser Experiment is a fascinating experiment in quantum mechanics that demonstrates several fundamental principles, including:Quantum superposition: Particles like photons can exist in multiple states simultaneously, like being both "up" and "down" in a spin measurement.Quantum entanglement: When two particles are entangled, their fates are linked, even if they are separated by vast distances. Measuring one particle's state instantly determines the state of the other, no matter how far apart they are.Complementarity: Observing certain aspects of a quantum system, like which slit a photon passes through, destroys information about other aspects, like whether it interfered with itself.Here's how the experiment typically works:A beam of photons is directed towards a double slit: This allows the photons to pass through either one of the two slits.An interference pattern is observed: If we don't know which slit the photons passed through, they "interfere" with themselves, creating a characteristic bright and dark pattern on a screen behind the slits. This is because each photon acts like a wave and can diffract through both slits simultaneously.A detector is placed near one of the slits: Now, when a photon triggers the detector, we know which slit it went through. Interestingly, the interference pattern disappears!The "eraser" comes in: In some versions of the experiment, another measurement is made on the photons after they pass through the slits. This can involve measuring their polarization or phase. Depending on the type of measurement, the interference pattern can reappear, even though we "know" which slit the photons went through!This seemingly paradoxical behavior highlights the strange nature of quantum mechanics. Measuring one aspect of a quantum system affects other aspects, even if they appear unrelated. The "eraser" doesn't actually erase the past path of the photons, but it somehow negates the information gained by the first measurement, allowing the interference pattern to re-emerge.There are several interpretations of the Quantum Eraser Experiment, each with its own implications. Some physicists believe it suggests that information about the past path of the photons is never truly lost, even if we can't measure it directly. Others argue that the experiment demonstrates the non-local nature of quantum entanglement, where measurements on one particle instantly affect the state of another, no matter how far apart they are.Overall, the Quantum Eraser Experiment is a powerful tool for exploring the mysteries of quantum mechanics and its implications for our understanding of the universe.