What is Interferometer: Definition and 177 Discussions

Interferometry is a technique in which waves are superimposed to cause the phenomenon of interference, which is used to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber optics, engineering metrology, optical metrology, oceanography, seismology, spectroscopy (and its applications to chemistry), quantum mechanics, nuclear and particle physics, plasma physics, remote sensing, biomolecular interactions, surface profiling, microfluidics, mechanical stress/strain measurement, velocimetry, optometry, and making holograms.Interferometers are devices that extract information from interference. They are widely used in science and industry for the measurement of microscopic displacements, refractive index changes and surface irregularities. In the case with most interferometers, light from a single source is split into two beams that travel in different optical paths, which are then combined again to produce interference; two incoherent sources can also be made to interfere under some circumstances though. The resulting interference fringes give information about the difference in optical path lengths. In analytical science, interferometers are used to measure lengths and the shape of optical components with nanometer precision; they are the highest precision length measuring instruments in existence. In Fourier transform spectroscopy they are used to analyze light containing features of absorption or emission associated with a substance or mixture. An astronomical interferometer consists of two or more separate telescopes that combine their signals, offering a resolution equivalent to that of a telescope of diameter equal to the largest separation between its individual elements.

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    Mach-Zehnder Interferometer at Wiki Question

    Can anyone help out? I was reading about MZ interferometers on Wikipedia http://en.wikipedia.org/wiki/Mach-Zehnder In the wiki article they have a picture of 4 samples of photon paths in a MZ interferometer. They indicate the probability of a finding a photon at detectors (A,B,C) for 3...
  2. C

    The Mach-Zehnder interferometer experiment

    hi all, I'm new here :shy: i'm italian, so i apologize for my english i never studied quantum physics (i only read scientific books) but i have a question that concerns the mach-zehnder interferometer experiment i hope you all know how this interferometer works, otherwise...
  3. Math Jeans

    Fabry-Perot interferometer diffraction

    Homework Statement A Fabry-Perot interferometer consists of two parallel half-silvered mirrors separated by a small distance a. Show that when light is incident on the interferometer with an angle of incidence \theta, the transmitted light will have maximum intensity when a = (\frac{m \cdot...
  4. R

    Horn Antenna Radio Interferometer

    This is a strange experiment (or not so compared to some of the experiments I've done) that I am currently undertaking, and require your help. I have built an interferometer of sorts. Two metal funnels of diameter 200mm are attached together by copper tubing (20mm?) through a Y junction with...
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    Fabry-Perot Interferometer as Principle for Bris-Minisextant

    I recently came across the Bris-Minisextant(wwwdotcassens-plath.de/catalog_web/096e_webdothtml) while researching sextants in general. While not truly a sextant in the conventional sense the device caught my attention and I started looking into what might be its underlying physical principle...
  6. S

    Double slit experiment / Quantum interferometer

    Hi I would really appreciate if someone could answer what maybe a really simple question. I'm no physics expert but I do read a lot and I have a keen interest. My question is related to light interference and the double slit experiment. I know that by observing which slit a photon of...
  7. L

    About observing the mewcury spectrum with a Fabry-Perot interferometer

    [SOLVED] About observing the mewcury spectrum with a Fabry-Perot interferometer Hello! I've been trying to observe the interference fringe pattern from a mercury discharge tube, but the pattern has not already shown up. I simply don't understand what I'm doing wrong. The first thing I did...
  8. S

    Fabry-Perot Interferometer: Energy Conservation

    Homework Statement This is regarding a Fabry-Perot Interferometer with identical mirrors: If you shine a beam of light on a 99% reflecting mirror, 1% goes through and the other 99% is reflected. But if a second mirror is placed behind the first one, where there is only 1% of the light...
  9. B

    Modified Mach-Zehnder Interferometer

    The Mach-Zehnder interferometer is shown in wikipedia and on David Harrison's page. If the second (upper right) half silvered mirror is taken away and no sample (as in the wikipedia setup) is in any of the two paths, I read that when sending individual photons through the device, roughly 50%...
  10. T

    Thin Film Interference (Interferometer)

    Homework Statement One of the beams of an interferometer passes through a small glass container containing a cavity 1.30 cm deep. When a gas is allowed to slowly fill thr container, a total of 236 dark fringes are counted to move past a reference line. The light used has a wavelength of 610...
  11. P

    Michelson interferometer maxima

    Homework Statement A Michelson interferometer uses light from a sodium lamp. Sodium atoms emit light having wavelengths 589.0 nm and 589.6 nm. The interferometer is intially set up with both arms of equal length (L1=L2) producing a bright spot at the center of the interference pattern. How...
  12. S

    Nightmarish michelson interferometer question

    We have to "closely spaced" frequencies f1 and f2. "The moving mirror moves at a constant speed v. Explain how the Doppler effect on the light reflected from the moving mirror affects the recorded signal as a function of time. Estimate the value of v required to resolve the freq. difference of...
  13. T

    Simple Interferometer question

    I've been doing some working with a michelson interferometer, specifically finding the refractive index of a glass block. I am given this eqn: n = (2t-ML)(1-cos)/ (2t (1 - cos) - mL) Where n is the refractive index of the glass M is number of fringes passing I have left the thetas out...
  14. Q

    Interference (Michelson Interferometer)

    Hello, . I have got a Michelson interferometer and measure a laser beam (HeNe @ 633nm). I move the mirror with a step motor of unknown step length and measure the intensity of the beam. I get a nice beat pattern out of that, with "wavelength" of the carrier wave being 14 steps and of the...
  15. B

    PASCO lab on the interferometer

    Hey guys, I did the PASCO lab on the interferometer the other day and just have a problem that I wouldn't mind knowing what caused it. here is the link to the PASCO lab manual: http://www.nhn.ou.edu/~johnson/Education/Juniorlab/Optics/Pasco_Interferometers.pdf Just in case you want to...
  16. Y

    Exploring Photon Behavior in a G Field with an MMx Interferometer

    I would assume there are experimental attempts to use an MMx type interferometer to check out some of the questions that are debated about photons in a G field. For example, if we have a single leg interferometer (no back and forth reflections to gain a greater effective length) and set it up...
  17. B

    Michelson Interferometer and white light fringes

    Hi, I conducted an experiment with the Michelson Inteferometer to obeserve white light fringes but I cannot explain the presence of a central black fringes. I understand a phase shift of pi is introduced in one of the beams but where/how does this shift occur? thanks
  18. T

    Interferometer questions, pure states?

    Hello, I have a few questions about this interferometer setup, see attached picture. The beamsplitters are 50/50 and the setup is symmetric. initial |i> first beamsplitter, where U is unitary and represents the beamsplitter. U|i> = 1/sqrt(2)( |u> + exp(ix)*|d> ) second beamsplitter, A...
  19. T

    Interferometer Capabilities for Detecting Wavelength Differences

    This is actually a copy of a thread I put in the Relativity forum because I figured interferometry was something of importance in that area but because the question is somewhat strange and might require direct experience I thought I'd copy it in here as well to see if someone might know...
  20. T

    Understanding Interferometers: Principle, Methodology, and Applications

    Please correct me if/where I'm wrong in my understanding of the following (laymans terms) explanation and question: A michelson interferometer like used in 1887 works off a basic principle of having the same beam of light arrive at the same place slightly behind/ahead of itself. We are able...
  21. M

    Why won't the bright spot in my Michelson Interferometer turn dark?

    Hi all, I've made a Michelson Interferometer with 635 HeNe, and I get nice, contrasty fringes. I have one problem - I cannot get the bright spot in the middle to turn dark! The intensity it has is like bright and brighter, but never dark. Any ideas why? The intensity of the two beams are...
  22. R

    Understanding Phase Difference, Diffraction & Michelson Interferometer

    Can anyone explain the following to me; what is phase difference and coherence? what actually is diffraction and why does it happen (is it something to do with Huygens principle?) why do you observe circular fringes when using the Michelson interferometer your help is much...
  23. P

    Acoustic Interferometer: Interference with the Quincke Tube.

    Acoustic Interferometer: Interference with the Quincke Tube. See here: http://www.mip.berkeley.edu/physics/B+35+05.html The diagram and physics suggests that acoustic interference is achieved through this simple device. Makes sense to me. However, with the potential for destructive...
  24. M

    Setting up Michelson Interferometer

    I was setting up a Michelson Interferometer the other day & was trying to adjust it so the movable & fixed paths are indentical in length. I could not really tell when they were identical so I asked a colleague. He told me that as the path lengths become equal, the spacing between the rings in...
  25. H

    Can You Build a Michelson Interferometer on a Budget?

    I have been thinking about building an interferometer (similar to the Albert-Michelson experiment)for my physics project to prove that the speed of light in vacuum is always constant. Are there any references that I can relate to building an interferometer?
  26. R

    RI using Michelson Interferometer, help please

    I'm doing a college project, and part of it involves finding the refractive index of a microscope cover slip. I am using a Michelson Interferometer, but the handbook for it is really badly written and coming to pieces, so I am a bit lost. This is what I have got so far: All that may or...
  27. R

    Understanding Interference Fringes in a Michelson Interferometer

    how can you tell whether the interference fringes are moving in or out as you change the distance between the mirrors by rotating the knob clockwise or counterclockwise. say if the circular fringes are moving toward the center of the screen than in what direction the knob is being rotated. my...
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