What is Wave and optics: Definition and 34 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. JasmineMasown

    I Huygens' principle doubt -- How do different shapes of wavefronts appear to the human eye?

    I learnt that wavefronts can be spherical, cylindrical or planar. But i wonder, if one were to observe light waves of different wavefronts with naked eyes, how would they appear? Would they appear all the same or would there be any difference in how we see them? Just a basic question that I felt...
  2. P

    B Looking for help understanding string theory

    String theory is a vast topic, and no grade 9 book will have content on it. However, no site or video gives it the attention this topic deserves, please input your understanding of string theory here. here are a few general questions to think about: 1)What is string theory? 2)Why was it made...
  3. 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)
  4. Mayan Fung

    Controlling output light power by constructive/destructive interference

    In optical communications, one of the modulation methods is to control the optical power (Simplest case, for example, bright = bit 1, dim = bit 0). I learned that we can achieve this by a Mach-Zehnder modulator (MZ modulator). Simply speaking, the principle of MZ modulator is to split the input...
  5. Elbraido

    B Compressing Light: Reflection in Small Gaps

    Hi thereLet’s consider a photon of wavelength λ is being reflected across of gap d meters. The photon is a reflected back and forth between the same points on two horizontal sheets that reflect 100% of the light. What happens when the distance is smaller than wavelength? Thanks
  6. filip97

    A Huygens Principle - how to explain this with classical language?

    I was read this article(https://engineering.purdue.edu/wcchew/ece604f19/Lecture%20Notes/Lect31.pdf). I was read this paper about Huygens' principle(https://engineering.purdue.edu/wcchew/ece604f19/Lecture%20Notes/Lect31.pdf) Main idea of Huygens' principle is how wave function ##ψ(r)##...
  7. K

    Diffraction Grating: Possible variables for Experiment

    For my High School Physics course, I have been tasked to design an experiment investigating the properties of a CD diffraction grating, and we MUST make a graph. Unfortunately, we only have two lasers of different wavelength, so changing the wavelength and measuring ##theta## would be a bad...
  8. nineteen

    Does speed of light depend on the wavelength or frequency of it?

    I heard that the speed of light doesn't depend on the wavelength or frequency of it, how does it happen? I don't understand it because the ultimate equation is c = fλ (where c is the speed of velocity of light, f is the frequency and λ is the wavelength of it...).
  9. 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...
  10. T

    Deflection of wave in dissipative media with a complex refractive index

    Homework Statement A monochromatic plane wave with wavelength 500µm is propagating through a dissipative medium with refractive index 1-0.0002i. It approaching the edge of the medium, and will pass out into free space. If the angle of incidence is not 90°, how much will the wave deflect as it...
  11. Michael Sullivan

    ABCD matrix for an optical system of two thick lenses

    Homework Statement I have an object at distance x1 from the first thick lens(convex) then air at distance x2 to the next thick lens(concave) then air of distance x3 to a mirror. I need to build an ABCD matrix representing this. Homework Equations thick lens equation: [ A B ] = [ 1-d/R1...
  12. F

    I Need to Calculate the Speed of Sound for a Lab

    Homework Statement Calculate the speed of sound in the classroom. You can use: Tuning forks, water, beaker, pvc pipe, ringstands, etc. Homework Equations v = f(wavelength) For fundamental frequency: L = 1/4(wavelength) For fundamental frequency: f = v/4L The Attempt at a Solution Here is...
  13. SunRay-dvsh

    A Why light beams attract or repel each other even when they don't have charge

    Hi, Can someone please explain as to why light beams attract or repel each other even when they don't have charge. Seems like it behaves like two current carrying parallel wires. There is very little material about this which goes completely above the head. Thanks
  14. B

    Refraction of IR "light" in CCD sensors SiO2 layer

    Dear friends I am new at this forum thank you for accepting my application first of all. My question is that I don't understand the optics/physics behind the reason why Si-based CCDs are not sensitive for IR-light (above 1000-1100 nm) if on the top of the p-type Si there is a SiO2 layer which...
  15. Peter Andrews

    Finding the angular spread of a diffraction minima?

    1. Homework Statement Light of wavelength 6000Å illuminates a single slit of width 10-4m. Calculate the angular spread of first diffraction minima.Homework Equations d*y/D = nλ Y = nλ/a for minima Y = (2n±1)λ/a for maxima Y stands for the position on screen, d is slit width and D is separation...
  16. SunRay-dvsh

    A Why is the Matter wave analogous to photon and derived from it?

    The electromagnetic wave derivation uses the fact that charge enclosed is zero and it goes to obey plane wave equations. Lets say we were deriving a wave equation from maxwell's equations for electron wave motion, but we assume that charge enclosed is not zero, and come up with some...
  17. P

    Diffraction Grating Question, Dispersion and Resolving

    Homework Statement One diffraction grating has 9600 lines uniformly spaced over a width of 3cm, it is illuminated by light from a mercury vapour discharge. The other has 5000 lines/cm and is a 3.5cm grating, this one is used in the second order to resolve spectral lines close to 587.8002 nm...
  18. Tareq Naushad

    Which properties of photons carry info on size,width,height?

    I know when we see an object then the frequencies of photons reflected from the object carry the information about the colors. Frequencies of visible spectrum helps us to visualize colors. However which properties of photons help us to estimate distance,speed,size,width,height,depth, plainness...
  19. S

    Point source of light, opaque screen with hole. photodiode problem

    Homework Statement A point source of light (wavelength \lambda = 600 \, \text{nm} ) is located a distance x = 10\,\text{m} away from an opaque screen with a small circular hole of radius b. A very small photodiode is moved on an axis from very far away toward the screen. The first...
  20. J

    Finding the magnetic vector potential

    I'm supposed to find the magnetic field, the scalar electric potential and magnetic vector potential for the following electromagnetic wave: \vec{E} = E_0 cos (kz - \omega t) \left \{ \hat{x} + \hat{y} \right \} Alright, the magnetic field goes as \vec{B} = \frac{1}{c} \hat{k} \times \vec{E}...
  21. E

    Wave reflection and refraction, relations between angles

    Hello! This post is strictly related to my previous one. Let's consider the same context and the same image. Regarding the oblique incidence of a wave upon an interface between two dielectric, all the texts and all the lectures write an equation like the following: e^{-j k_1 y \sin \theta_i} +...
  22. rkrishnasanka

    Is pertubation a linear operation?

    My question stems from a discussion I had with my colleague today. In Electomagnetic coupling , like in waveguide structures. We apply pertubation theory to find out the coupling between various modes that get coupled in the device. My colleague said that the coupling interaction was...
  23. kelvin490

    X-Ray Diffraction in Crystals: Exploring Scattering & Interference

    In explaining x-ray diffraction of crystals, usually the approach is to consider the atoms absorb radiation and scatter it, at some angles constructive interference occur and bright spots can be observed. It seems that it is different from the diffraction of slits or gratings because in these...
  24. kelvin490

    Question about dark fringe in diffraction

    In finding the angle for the mth dark fringe of single slit diffraction using Huygen's principle, they usually split the slit into equal portions. For example, to find the first dark fringe the slit is split into two equal spacings and if the path difference between the edge and the middle point...
  25. A

    Understanding the Wavelength of Light: Explained Simply | 750 nm Explanation

    Hi 1)Is this sentence right? When we say for example the wavelength of red light in vacuum is 750 nm it means that the length of electric field and magnetic field that are perpendicular in the propagation direction of wave is 750 nm in one cycle? 2) We say that oscillating charges in antenna...
  26. kelvin490

    Question about intensity of EM waves

    For electromagnetic wave if it's reflected from a perfect conductor standing wave can be form. I wonder why Poynting vector can be used to describe the intensity of standing EM wave. (see p.19 of http://web.mit.edu/viz/EM/visualizations/coursenotes/modules/guide13.pdf ). From some textbooks...
  27. K

    Picture of Bragg's diffraction sounds confusing

    This may be a little of a stupid question. But I was looking at a diagram describing Bragg's Law of Diffraction. and I was like...how can an interference happen if wave beam C and wave beam C' are hitting different points on the detector screen?! they are not hitting the same point on the...
  28. vead

    TEM TE and TM Modes for Waveguides ?

    hello ; I need some help.I reading about TEM TE and TM Modes for Waveguides. actually I need some equations for Planar wave guide and optical fiber wave guide. I did google search. I don't understand how to write equation step by step for planar wave guide I found this link...
  29. F

    What is the range of optical frequecy?

    I see the term o"ptical frequency" in some articles. From Wikipedia I read that it means the whole EM spectrum. But something says to me it may be only the visible part of the spectrum. Now, which definition is correct? Thanks
  30. F

    What are diffraction orders in nano-structures?

    Can someone please describe the diffraction orders on a nano-grating? I am reading articles about imaging devices, and I cannot understand the diffraction orders For example, incident wave can be mapped into a propagating wave through the -1, 0, and+1 diffraction orders. Is any of these...
  31. F

    What is a broadband field?

    Is broadband field, a wave that contains a range of wavelengths? I can not find a good definition for it
  32. Z

    Reflection and Refraction of Electromagnetic Waves at a Glass-Air Interface

    1. Consider a y-polarized electromagnetic wave with vacuum wavelength 600nm that is propagating in glass and then incident on a glass-air interface; use n=1.4 for glass. Take the interface surface to be the y-z plane, and the plane of incidence to be the x-z plane. Consider 2 incident angles...
  33. G

    Solving Wave & Optics Questions - Help Needed

    hey guys i have two questions that i wouldn't mind some help on ! firstly a wave in the form (in meters) of y = 0.5sin(4(pi)t+0.5(pi)x) where t and x are time and space co-ordinates in seconds and meters find the wave length amplitude frequency and speed of the wave. is the wave...