Optics Definition and 999 Threads

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. Sokolov

    Irradiance of light trapped between two parallel mirrors

    The setup of the problem is shown in the image below. I know that I must add all the contributions of each reflected ray and that its amplitude will be reduced by a factor ##r## each time it is reflected. So after the n-th reflection, its amplitude will be ##E_0r^n##, with ##E_0## the amplitude...
  2. Sokolov

    Intro Physics Textbooks on Optics: Alternatives to Hetch-Zajac's "Optics"

    I'm looking for an alternative textbook to the Hetch-Zajac's one. I am a physics undergraduate student, and this is the recommended book for the subject, so I would like to find a book that covers more or less the same topics. There are two main problems I find at Hetch: Firstly, its extreme...
  3. S

    A Evanescent field of a waveguide

    If we look to the figure, in several articles they mentioned that the part of the mode field, the tail of the mode field diameter, travel in the cladding, this maybe I can understand that because of a little change between the refractive indices of the core and the cladding, then the transverse...
  4. S

    Polarization and intensity of a Gaussian beam

    The equation above (from Wikipedia), assumed that the Gaussain beam has polarization in x-direction, as I know that the polarization means that the oscillation direction of the electric field and so the intenisty... so how we get circular intensity in every direction which means in x and y...
  5. Haorong Wu

    Quantum Need suggestions about textbooks on optics

    Hi, guys. I need 2 textbooks for my graduate courses, including quantum optics and nonlinear optics. Thanks!
  6. Ozen

    Ray Diagram for an Experimental Lens Systems

    Hello, I wanted to confirm a suspicion with how the Aimpoint optics work, but to do that I need to do some ray diagrams. I only ever did them with simple convex, concave, and spherical systems while at college. From what I already know of how reflex sights work, the LED is placed at the focal...
  7. A

    A Piezoelectricity and the Lorentz Harmonic Oscillator?

    Hi! As I outlined in my https://www.physicsforums.com/threads/hello-reality-anyone-familiar-with-the-davisson-germer-experiment.985063/post-6305937, I'm curious to ask if there is anyone with knowledge on the theory of the piezoelectric effect on this forum? I think it's fascinating how a...
  8. K

    Calculate the focal distance of the duplicate

    The picture below shows a so-called chromatic doublet, which is designed to minimize chromatic aberration, ie the wavelength dependence of the refractive index of the glass. The first lens has a flat first surface and a concave second surface with radius of curvature R and index of refraction n1...
  9. H

    Problem about compound optics in microscopes

    angular magnification=9.62 part a 1/s+1/s'=5 1/(25-s-s')+1/s"=1/2.6 -s"/s=m can't find m, don't know how to use the info that a person of normal eyesight is looking into the microscope.
  10. S

    Optics: Destructive Interference

    I thought if the question asks for the first minimum or the first dark fringe you use (m+1/2) but i am not getting the right answer. I was hoping if someone could tell me in what situations the (m+1/2) would apply? Thanks in advance.
  11. 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...
  12. 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...
  13. 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.
  14. 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...
  15. jisbon

    Optics (dealing with 2 sources of wavelength)

    To start off, I dealt with questions similar to this, but it only involves one wavelength. Now that there's 2 wavelengths, I'm kind of stumped as to what I should do. Since the question stated a second dark fringe, I can assume that it will be a destructive interference. Since the rays are...
  16. E

    Optical wireless communication ideas

    Hello PF! I have developed a recent interest into electro-optics used in communication systems. Specifically speaking, I am mostly interested into Optical wireless communications and their applications, for terrestrial to satellite communication. I am considering to do a research project for my...
  17. jisbon

    Finding the distance in an optics system

    Hi all, Pretty new to optics here, so would like to get my basics right. Below is my working, was wondering if my concepts are correct here. First I will separate mirror and lens and solve them 1 by 1, so solving for mirror first, ##\dfrac {1}{p_{1}}+\dfrac {1}{q_{1}}=\dfrac {1}{f_{1}} ##...
  18. J

    Why is milk smoother and flatter than water?

    I have conducted an experiment involving projecting a laser beam onto a surface and observing speckles that move relative to us. Those speckles become less visible (maybe smaller?) when the surface is smooth and that is especially the case with milk. I have dyed milk and water to see whether in...
  19. E

    I Holography used in telecommunications

    Hi PF! I am interested to know whether there are applications of holography in telecommunications, and if there is research on this topic. If there is some literature on this topic (provided holography is used in computer networking) where I can read and learn more in-depth about this topic, I...
  20. Kaelor

    Inserting thick lenses into a thin lens system and deducing values

    Homework Statement:: Finding the distance between the back surface of the first lens and the front surface of the back lens. Homework Equations:: 1/f = 1/s_o + 1/s_i I have two positive thin lenses that are separated by a distance of 5 cm. The focal lengths of the lenses are F_1 = 10 cm and...
  21. C

    Optics focal length and optical power Question

    1/f = 1/dₒ + 1/dᵢ = 1/1.0 + 1/0.33 = 4.03 m (focal length) Power: 1/4.03 m or 0.248 (0.25) *around to the2 decimal points? or leave it as a fraction? ((Did I do this correctly? I am not sure if this is correct and is it okay to be in meters not centimeters?)) Please let me know!
  22. O

    Diffraction pattern due to a lens with focal length f

    Suppose one light up with a laser on a grid with grid constant g. The grating is followed by a focusing lens with a focal length of f. In the focus (or immediately in front of it) the maxima have a distance d. How large was the distance of the maxima immediately after the grating? scheme: Laser...
  23. peace

    Elliptically polarized light & partially-polarized light

    How to distinguish elliptical polarized light from partially-polarized light?
  24. M

    Combination lens equation questions

    Homework Statement: Lens questions. Homework Equations: idk Hello, so I was wanting to use a laser beam and purchase a few lens' online for a project and wanted to get something similar to the image below, where i would end with a horizontal light ray i was wondering if anyone knows the...
  25. e101101

    Optics Problem: What optical instrument does this?

    Im thinking that this is a telescope, but I am having a lot of trouble answering this question. If the plane waves arrive at different angles, wouldn't the image be distorted?Would the lenses possibly be spherical because of this?
  26. e101101

    Hecht optics: Request for screenshot of this figure please

    Can someone simply screenshot this figure and send to me: Consider Figure 5.4 d) on page 153 of Hecht. As shown, converging rays that are headed toward the point F convert to a plane wave upon hitting the boundary between n2 and n1.
  27. 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...
  28. D

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

  29. 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...
  30. D

    Optics: refraction and reflection

    Homework Statement: I have no idea how to start with this problem. I am trying to look for all the incident angles, refraction and reflection angles. And i don't know what the two radii are doing with y. Homework Equations: critical angle = arcsin (n2/n1) snell's law for refraction...
  31. Duboo

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

  32. 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...
  33. B

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

    This problem was asked in one of the most prestigious exams in India: JEE Advanced, unfortunately it was considered to be ambiguous for the scope of given examination and hence no official answer is issued for it as such.(BONUS marks to all) And so many solutions were posted on Internet which...
  34. S

    Building a small pattern projector

    Summary: calculation a projection lens system for a pattern projector Summary: calculation a projection lens system for a pattern projector Hello, I want to build a small pattern projector. This projector should project a pattern on a wall, which is 200mm away from the projector. The size...
  35. B

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

    I've tried to attempt the first part of the problem(spent over an hour on this) as second part could be easily optained with some calculus ,I asked my friend but alas nobody could conjure the solution to this dangerous trigonometric spell. It was just pages and pages of concoction of...
  36. christang_1023

    Derivation about the wave interference

    Starting from the simple case, there is a single wave ##e=a\cos(2\pi ft+\frac{2\pi}{\lambda}x+\phi_0)##, and integrate in such a way, where ##T_{eye}## stands for the response time of human eyes' response time towards energy change: $$I=\int_{0}^{T_{eye}}e^2dt$$ The calculation includes...
  37. 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.
  38. 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...
  39. A

    I Calculate Retinal irradiance - from photometric units

    I have been trying to calculate what retinal irradiance value I get with a 1 blue LED system. Since the manufacturer didn´t give the spectral distribution information, I will approximate LED as a monochromatic one (using the 460 nm peak). From the datasheet, the LED intensity range goes from 6...
  40. PhysicistSarah

    What to Do With TV Projector Optics?

    Summary: Got some high quality lenses. hat can I do with them? I acquired some high quality optics from a projector style TV that I took apart for it's mirror and a few other things. I got some high quality lenses though. I'm interested in astronomy and physics demonstrations because it gets...
  41. B

    Question about the derivation of linear magnification

    I tried assumed ##\theta \approx sin \theta \approx tan \theta##. By Snell's law(after approximation), $$n_1 \tan( i_1)= n_2 \tan( i_2)$$ If ##\tan (i_1)=\frac {h_o}{ u}## and ##\tan (i_2)=\frac {h_i}{ v}##,then $$m=\frac {h_i}{h_o}=\mod{\frac {v n_1}{un_2}}$$ Which is the expected...
  42. fernelau

    Understanding the Impact of Convex Lens Focal Length on Water Temperature

    Summary: Hi, I'm doing an assessment for Physics on Optics topics, but I can't really explain how the CV affect the RV CV : Focal length of convex lens RV : Temperature of water after 20 minutes under the sun How I should explain for the temperature difference? 🤔 Please help, Thanks.
  43. 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...
  44. 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
  45. 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...
  46. 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.
  47. W

    A How to Calculate Photon Detection from Output State in Quantum Optics?

    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...
  48. 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...
  49. 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...
  50. 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...
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