What is Optics: Definition and 999 Discussions

Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.Most optical phenomena can be accounted for by using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be accounted for in geometric optics. Historically, the ray-based model of light was developed first, followed by the wave model of light. Progress in electromagnetic theory in the 19th century led to the discovery that light waves were in fact electromagnetic radiation.
Some phenomena depend on the fact that light has both wave-like and particle-like properties. Explanation of these effects requires quantum mechanics. When considering light's particle-like properties, the light is modelled as a collection of particles called "photons". Quantum optics deals with the application of quantum mechanics to optical systems.
Optical science is relevant to and studied in many related disciplines including astronomy, various engineering fields, photography, and medicine (particularly ophthalmology and optometry). Practical applications of optics are found in a variety of technologies and everyday objects, including mirrors, lenses, telescopes, microscopes, lasers, and fibre optics.

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  1. S

    A Mode Field Diameter and Penetration depth of the Evanescent field

    Source: fobasics.blogspot.com Source: scirp.org As it is shown in the first pic above that the mode field diameter is defined as the mode field decreases to 1/e (in intensity 1/e^2), if I take the mode field and subtract the core's diameter then I divide it by 2, should I get the penetration...
  2. N

    Image position in an optical system?

    I have an plano-convex lens with focal length 75 mm. The object is 325mm from the lens. a) Where is the location of the image after the lens? b) Where is the location of the image if an beamsplitter is placed after the lens? My solution, questions: a) a = 325 mm b = ? mm f = 75 mmm...
  3. S

    Aerospace Engineering Graduate Student

    Hello everyone, I am a PhD candidate researching optical diagnostic techniques. I am looking to receive and give help with pulsed laser systems.
  4. 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...
  5. jisbon

    Optics (dealing with 2 sources of wavelength)

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  6. E

    Optical wireless communication ideas

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  7. jisbon

    Finding the distance in an optics system

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  8. J

    Why is milk smoother and flatter than water?

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  9. E

    I Holography used in telecommunications

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  10. Kaelor

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  11. C

    Optics focal length and optical power Question

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  12. O

    Diffraction pattern due to a lens with focal length f

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  13. peace

    Elliptically polarized light & partially-polarized light

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  14. M

    Combination lens equation questions

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  15. e101101

    Optics Problem: What optical instrument does this?

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  16. e101101

    Hecht optics: Request for screenshot of this figure please

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  17. NP04

    What are the variables in the equation λ=xd/L in Physical Optics?

    I know I have to use λ=xd/L. But I don't know what any of those variables (except lambda) mean. If you assume that 0.59 is x times d, you can get an answer that is close. 0.59/100 = 5.9*10^-3. Can someone explain the solution and meanings of variables using a diagram? (The answer to the...
  18. D

    Physical optics -- counting interfence fringes to measure a length change

  19. J

    Fourier transform fallacy? (Optics)

    Here it goes. I have been taught that a finite pulse of light does not have a single frequency. By finite pulse I was given an example of a source of light that has been emitted during a finite amount of time and, consequently, covers a finite region of space. Then I was taught that you can...
  20. D

    Optics: refraction and reflection

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  21. Duboo

    What is the relationship between angle and polarization in modern optics?

  22. B

    Electric field of light emitted by atom, given the intensity

    For t < 0 , all I can think of is a qualatative " the field is zero because the intensitity is 0 when the burst of light hasn't been emitted yet " For t >= 0 , I've tried squaring the given E and that let's me say the amplitudes are proportional (with a cos^2 term in the mix) But I feel like...
  23. B

    An ambigious optical system with ambigious solutions [JEE Adv - 20`16]

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  24. S

    Building a small pattern projector

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  25. B

    Jenkins-White Optics: Relation between Prism/Deviation Angle and Rays

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  26. christang_1023

    Derivation about the wave interference

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  27. Abhimessi10

    Engineering Houston's piezoelectric method for finding the velocity of light

    Crystal acts as a diffraction grating.Although I don't know what that means.
  28. shahbaznihal

    Location of a diffraction pattern

    I am trying to make a spectrometer. At the moment, I have an optical setup consisting of a laser, diffraction grating and a screen/detector in a straight line. I am trying to understand how to estimate the location of the diffraction pattern of the slit on the screen? Is it the same location on...
  29. A

    I Calculate Retinal irradiance - from photometric units

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  30. PhysicistSarah

    What to Do With TV Projector Optics?

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  31. B

    Question about the derivation of linear magnification

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  32. fernelau

    Understanding the Impact of Convex Lens Focal Length on Water Temperature

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  33. T

    Strange Optical Effect: See CD Fully Visible & Ruler Bulging

    In the picture a CD is held in front of a ruler. The light source is an ordinary lamp. You can see a shadow of the CD on the ruler. Remarkable is the shadow on the screen behind it, because you can see that the CD is fully visible and the ruler bulges instead. Does anyone know this optical...
  34. microsansfil

    A [Quantum Optics] "quantumness"

    Hi, In this presentation slide 17 it is mentionned : Is there any confusion with the fact that coherent states are said to be semi-classical ? /Patrick
  35. T

    Understanding Waveform & Autocorrelation in Pulse Lasers

    So, I was working on autocorrelation for my pulse laser system and I started to wonder what is the difference between single wave with 400nm of wavelength and two 800nm waves overlapped. In the knowledge, I know of, is that wavelength is the length between two picks. And when it is pulse laser...
  36. DharshanT

    Finding the magnification of a ball lens

    I don't really know how to relate the effective and back focal lengths for magnification purposes. Literature review suggests that a lens of 1mm diameter can have a magnification of 350x-400x, but I don't really know the calculations behind it. Please advise.
  37. W

    A Quantum Optics statistics

    Hi everyone, I am following along with the MIT OCW quantum optical communication course. I have a question about this chapter, concerning the linear attenuators and amplifiers. Specifically, the chapter mentions that they are not going to get ##\rho_{out}##, but I am interested in this. More...
  38. S

    Modes and Q-factor(s) of a random laser

    Many papers about random lasers mention the Q-factor of random lasers. Since a random laser has multiple peaks close to each other like shown in the figure. Does each of these peaks correspond to a unique random lasing mode, or is it just a single mode? Similarly what is the right way to...
  39. Sophrosyne

    Why light slows in transparent media

    I was watching this video by Don Lincoln, one of the senior researchers at FermiLab, on the the reason light slows down in transparent media (air, water, glass, plastic, etc...). He explains that the photons excite the electrons in the medium, which in turn add to the wave (or at least that's...
  40. M

    A Reviewing Spectral Imaging Techniques

    I am writing a review on snapshot spectral imaging techniques, and, being mainly interested in visible applications, I looked into spectral analysis with light field cameras, which have been rather popular in the previous years (see wikipedia): the main reference for these systems, at least for...
  41. R

    I Beam-splitter transformation matrix

    The transformation matrix for a beam splitter relates the four E-fields involved as follows: $$ \left(\begin{array}{c} E_{1}\\ E_{2} \end{array}\right)=\left(\begin{array}{cc} T & R\\ R & T \end{array}\right)\left(\begin{array}{c} E_{3}\\ E_{4} \end{array}\right) \tag{1}$$ Here, the amplitude...
  42. C

    How can I derive Eq 9.5.11 in Scully's Quantum Optics

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  43. D

    Interferometry (testing of optics)

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  44. Andy Resnick

    New Optics Toy: A 'Varicolor' filter

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  45. R

    Frequency to temporal period conversion

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  46. mikenw

    Curious optical effect related to light passing through a mesh

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  47. Chestermiller

    Possible to prove mathematically that the football spot was bad?

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  48. Adgorn

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  49. Seanskahn

    Are there still open problems in classical wave optics?

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  50. M

    Numerical aperture of a Keplerian telescope

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