What is Wave optics: Definition and 46 Discussions

In physics, physical optics, or wave optics, is the branch of optics that studies interference, diffraction, polarization, and other phenomena for which the ray approximation of geometric optics is not valid. This usage tends not to include effects such as quantum noise in optical communication, which is studied in the sub-branch of coherence theory.

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  1. A

    B Explanation for bright fringes in Single Slit Diffraction

    In Young's Double Slit Experiment, we were shown the complete derivation for location of fringes, width of fringes etc. on interference by two point sources of light and all was well. In Single Slit Diffraction we were just asked to remember the formulae as they were with little explanation. I...
  2. brochesspro

    Effect on visibility of thin films due to interference

    So, what I do not understand 1st and foremost is, when they say "see the film", does the light have to be reflected from the film or can I consider refraction of light through thin film also a case using which image can be formed? To be honest, I have solved this question before, but the problem...
  3. PhysicsRock

    2D Fraunhofer-diffraction with infinitely long slits

    My issue here is the fact that the slits are supposed to infinite in the ##y##-direction. With what's given in the assignment, I'd define the apparatus function ##a(x,y)## as $$ a(x,y) = \begin{cases} 1 & , \, ( 9d \leq |x| \leq 10d ) \wedge (y \in \mathbb{R}) \\ 0 & , \, \text{else}...
  4. Lotto

    What is the length of an infinite potential well for an electron?

    I have a nanoparticle of cadmium selenide with a diameter d. When it emits a photon with a wavelenght lambda, it happens because an electron jumps from the conduction band to the occupied band across a forbidden band. I can suppose that jump as a jump from a higher energy level (the conduction...
  5. yucheng

    Visualizing the Paraboloidal Wave

    We can either plot the real part of the complex amplitude, or the wavefront. However, how is wavefront meaningful for varying amplitude? In order to plot the paraboloid, we must vary ##z##, which varies the amplitude ##\frac{A_0}{z}##. Unless the amplitude is varies little, i.e. ##1/z##...
  6. yucheng

    I Validity of Fresnel Approximation

    Wikipedia says that Fresnel diffraction is valid if the Fresnel number is approximately 1. What Fresnel number then is the Fresnel approximation for paraxial-paraboloidal waves valid? It's not mentioned... Oh I just realized that $$\frac{N_F \theta_m^2}{4} \ll 1$$ So it depends on the maximum...
  7. Philip Koeck

    A Diffraction of spherical wave by plane grating

    Textbook examples usually involve a plane monochromatic wave that is diffracted by a plane grating. If one places an ideal focusing lens behind the grating one will get a diffraction pattern in the back focal plane of the lens. The geometric size of this diffraction pattern is proportional to...
  8. V

    Best layman non mathematical interesting book on Ray and wave optics

    A book on optics which is less mathematical maybe a similar one to physics for poets or gamow gravity classics
  9. wcjy

    Can Small Errors in Path Difference Affect Double Slit Interference Patterns?

    $$Δφ = 2π \frac{L_2 - L_1}{λ}$$ $$Δφ = 2π \frac{\sqrt{0.016^2+10^2}-\sqrt{0.014^2+10^2}}{560*10^{-9}}$$ $$Δφ = 33.659 rad$$Answer = 2.24 rad (unsure if the answer provided is correct/wrong)
  10. Seanskahn

    Are there still open problems in classical wave optics?

    I have been revisiting my notes from my 2nd and 3rd year physics degree - especially the ones covering Fourier Optics, and other classical wave optics - and it is quite rewarding to revisit the historical / exploratory aspect of the series of discoveries, that built the foundations of this...
  11. A

    Interference fringe pattern on a thin cut cylinder slice

    A thin slice is cut out of a glass cylinder along a plane parallel to its axis. The slice is placed on a flat glass plate as shown in the figure. The observed interference fringes from this combination shall be ______. My thoughts The thin slice will act as thin film but of half cylindrical...
  12. Bheshaj

    Wavefronts: Understanding Wave Optics

    What Is a wavefront? How can we interpret it?
  13. Erickly

    Film Thickness for Minimum Reflection of Monochromatic Light: How to Calculate?

    Homework Statement Monochromatic light of wavelength, λ is traveling in air. The light then strikes a thin film having an index of refraction n1 that is coating a material having an index of refraction n2. If n2 is larger than n1, what minimum film thickness will result in minimum reflection of...
  14. Abhimessi10

    What is the Number of Fringes in a YDSE with Given Parameters?

    Homework Statement Find number of fringes separated by 1 cm on a screen at a distance of 2mm from slits which are 0.2mm apart from each other.The wavelength of light used is 500nm. Homework Equations The Attempt at a Solution I really don't know any way to solve it.I have tried putting unit...
  15. T

    Wave optics / Snell's law of refraction

    When light from a rarer medium enters a denser medium, the wave gets refracted into the denser medium and so the wavelenght and the speed of propagation decreases ( [v][1] >[SUBv][/SUB2]) but the frequency remains the same. HOW ? [SUBv][/SUB1] / [SUBλ][/SUB1] = [SUBv][/SUB2] / [SUBλ][/SUB2]...
  16. rkatcosmos

    Using multiple mirrors in Michelson Interferometer

    The number of mirrors typically used in Michelson Interferometer is 2. I am looking up the respective Wikipedia article and MIT's youtube video. I am wondering, for the sake of one of my experiment, whether more than 2 mirrors can be used in the interferometer? I require the traversing mirror...
  17. Lensmonkey

    2 layers of birefringent crystal, how many rays?

    I am trying to solve a problem my camera exhibits. It has a sensor with 6000x3376 pixels. HD video is 1920x1080. In order to reduce the amount of information to the processor the camera throws away 2 out of 3 pixel lines. this creates a problem with thin lines tike telephone lines and makes...
  18. P

    Wave Optics: Electromagnetic Waves

    " Thus according to Maxwell, light waves are associated with changing electric and magnetic fields; changing electric field produces a time and space varying magnetic field and a changing magnetic field produces a time and space varying electric field. The changing electric and magnetic fields...
  19. Christian Grey

    Astrophysics uses wave optics or geometrical optics?

    I know Astrophysics uses concepts like relativity etc. But I want to know does it uses wave optics or geometrical optics? The phenomenon of light,wave optics(reflection,refraction,polarization,diffraction and interference) that we see everyday, is used in Astrophysics? Or does it uses...
  20. Jordaniel

    Seeing UV & IF Light: Exploring My Perception

    When I observe the UV light emitted, I can literally see the millions of photons appear and die within milliseconds, but nobody else around me can. When I observe IF light sources and transmitters in low light, it is the same characteristic, except there only appears to be to photon sources, and...
  21. W

    Problem with wave optics - diffraction grating?

    Homework Statement For your science fair project, you need to design a diffraction grating that will disperse the visible spectrum (400-700nm) over 30 degrees in first order. How many lines per mm does your grating need?Homework Equations sin(Θ) = mλ/d y = Ltan(Θ) I'm pretty sure the only...
  22. S

    Does a diffraction grating with a shape form fourier image

    i just wanted to get this cleared that a beam falling on a diffraction grating with a shape gives the Fourier images of the grating object which can be reobtained by placing a biconvex lens that would converge the rays and form a focussed Fourier image at its focal length and the image of the...
  23. AdityaDev

    Optics Homework: Converging Lens and Varying Refractive Index

    Homework Statement A rectangular slab of length l=20cm and thickness d=4cm is placed in left of a converging lens of focal length f=20cm. A screen is placed in the focal plane plane of lens (right side of lens).Refractive index of the material of slab increases linearly from u0 at the bottom by...
  24. hdp12

    Wave Optics & Two-Slit Interference Explanation

    I have an online homework question and my classmate told me the answer but I would really like someone to explain to me how that answer was determined. I do not understand. Q: Consider the electric field observed at a point O that is far from the two slits, say at a distance r from the midpoint...
  25. G

    Diffraction gratings and angular separation

    Hello everyone, I came across the following when I was reviewing diffraction gratings: "The condition for maximum intensity is the same as that for a double slit. However, angular separation of the maxima is generally much greater because the slit spacing is so small for a diffraction grating."...
  26. G

    Schlieren Imaging / wave optics

    Could anyone please explain or advice me where to read about principles of Schlieren image formation NOT in terms of ray optics, but in terms of wave or Fourier optics. I understand how that works in terms of heuristic ray optics, but would like to get to know how the actual image formation...
  27. H

    A lot of questions about wave optics

    Homework Statement In this picture,the ray b and c are parallel.So why there are interference occur? Homework Equations The Attempt at a Solution
  28. J

    Why only electric field is considered in Wave optics?

    While studying polarization I came to a word "Electric field vector" and not "magnetic field vector". Then after reading certain references I came to know that it is electric field which is considered in wave optics. Why is Magnetic field not considered??
  29. cryora

    Wave Optics (Interference due to reflection)

    Homework Statement A radio-wave transmitter and a receiver, separated by a distance d = 50.0m, are both h = 35.0m above the ground. The receiver can receive signals directly from the transmitter and indirectly from signals that reflect from the ground. Assume the ground is level between the...
  30. P

    Calculate Microwave Frequency for Interference Pattern | Wave Optics Question

    Homework Statement a microwave source is placed behind two identical slits, as represented in the diagram above. The slit centers are separated by a distance of 0.20m, and the slit widths are small compared to the slit separation but NOT negligible. The microwave wavelength is 2.4X10^-2m. The...
  31. J

    Modern Wave Optics Question

    Homework Statement Given two counter propagating monochromatic electromagnetic plane waves with equal strength and frequency but orthoganal polarization, (one is y polarized, the other is z polarized). More specifically, the z polarized wave is traveling in the positive x direction and the y...
  32. A

    Why can't we form an image with just one ray of light?

    In geometrical optics we consider that an image is formed at the point where two rays meet. But meeting of two rays will just create a change in intensity, that too will change according to phase difference. Also if the intensity say doubles it will make the image better visible but we...
  33. B

    Lens design and wave optics

    Hello, I would like to ask a question on lens design. My goal is to design a lens for CMOS cameras and the objective is: shooting things at 2cm near magnification ratio is about 1/2 completely monochromatic I was wondering does designing lens like this involve any knowledge on theoretical...
  34. R

    Lots of questions on wave optics

    Why if you shine a flashlight on the wall, the circle of light is bigger than the opening of the flashlight (the aperture)? If I attach a pipe (of the same radius as the opening of the flashlight) to the aperture so that light has to go through the pipe, then geometrically the circle of light...
  35. K

    Wave optics and diffraction gratings

    Homework Statement I'm really struggling with this one. "A diffraction grating with 600 lines/mm is illuminated with light of wavelength 500 nm. A very wide viewing screen is 2.0 m behind the grating." a) What is the distance between the two m=1 fringes? b) How many bright fringes can...
  36. K

    Wave Optics - Size of Illuminated spot on a screen

    Homework Statement A convex lens has a radius of 20mm and a focal length of 100mm. A point source of light is placed 500mm behind the lens and a screen is placed 120mm in front of it. Calculate (to first order) the size of the illuminated spot on the screen. Now calculate the distance at...
  37. T

    Solve Wave Optics Laser Homework: Find Slit Width w/ Helium-Neon Laser

    Homework Statement I have a few questions because of the fact I just don't understand any of this... 1.A helium-neon laser (l=656 nm) illuminates a single slit and is observed on a screen 1.9 m behind the slit. The distance between the first and second minima in the diffraction pattern is...
  38. H

    Wave optics YOUNG'S DOUBLE SLIT EXPERIMENT

    Hi, I'm encountering problems in my tests about young's double slit experiment and in many of those I'm finding the source executing simple harmonic motion (whose equation is given ) and we are asked to calculate the equation of motion of central bright fringe,max no. of fringes that can be...
  39. L

    Wave Optics: Light in Water & Glass Wedge - Find Thickness/Angle

    Homework Statement Light of wavelength 640 nm in water illuminates a glass (n = 1.5) wedge submerged in water (n = 1.33). If the distance between successive bright fringes is 6mm. Find a) the change in thickness of the glass between these fringes and b) the angle of the wedge Homework...
  40. L

    What Wavelengths Are Missing in the Reflected Light from a Thin Film Coating?

    Homework Statement A coating of film n=1.37 on glass slabs (n=1.6) is 8.45X10^-5 cm thick.If white light is incident normally, which visible wavelengths are missing in the reflected light? White light containing wavelengths from 400 to 700 nm. Homework Equations The Attempt at a...
  41. J

    The Minimum Angle for No Sound Transmission Through a Doorway

    Wave Optics! Homework Statement Sound with frequency 1240 Hz leaves a room through a doorway with a width of 1.19 m. At what minimum angle relative to the centerline perpendicular to the doorway will someone outside the room hear no sound? Use 344 m/s for the speed of sound in air and assume...
  42. S

    Fringe spacing for a diffraction grading (wave optics)

    Homework Statement A 550 lines/mm diffraction grating is illuminated by light of wavelength 550nm. How many bright fringes are seen on a 3.1-m-wide screen located 2.1m behind the grating? Homework Equations \DeltaY = \lambda*L/d where Y is equal to the fringe spacing... lamda is...
  43. T

    Wave optics interference and diffraction

    Imagine you are trying to measure the width of a single strand of spider web. You have fastened the web to the slide, only rather than mounting the strand vertically as you did with the hair, you have mounted it horizontally. You illuminate the strand with a 650nm laser and project the resulting...
  44. G01

    Wave Optics Problems: Diffraction Grating #1 & #2

    #1 A diffraction grating having 500lines/mm diffracts visible light at 30 degrees(\pi/6) What is its wavelength? the distance between slits is .002mm(500l^-1) d\sin\frac{\pi}{6} = \lambda = 1000nm, which is too big. The answer is 500nm. What am I doing wrong? #2 The slit spacing in a...
  45. N

    What is the meaning of N in wave optics of reflection?

    Hi, Right now I am solving some exercises in connection with wave optics. If we have three layers of different materials (ex. air, gasoline, water) and we send a light ray through these layers and we calculate the wave length of the reflected rays, then we use these formulas: D = N*l; (D =...
  46. A

    Wave Optics - Single Slit Diffraction

    Light of wavelength 600nm falls on a 0.40-mm-wide slit and forms a diffraction pattern on a screen 1.5m away. (a) Find the position of the first dark band on each side of the central maximum. (b) Find the width of the central maximum For the (a) I think that we use sinθ = +- λ / α I...
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