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. Antraxius

    Designing a planocovex PMMA lens

    As an electrical engineer, I am an amateur on optics, but I really could use some help. I am making a lens of PMMA, 2D. To 'convert' a rotary movement into a sweep. The lens needs to be 120mm long, with its focus at a max distance of 80mm the light traveling out of the lens needs to be parallel...
  2. 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...
  3. Ian Baughman

    Polarizers and Analyzers in optics

    If we have a polarizer and an analyzer where the angle between the two axes is ∅ then we can find the intensity using Malus's Law. The intensity after the polarizer would be: (1/2)I0 After the Analyzer we could have an intensity of: (1/2)I0cos2(∅) What would happen though if ∅ = 0. Would...
  4. S

    A Kelvin Units: Help Understand Optics of Graphene

    Hey! In https://www.researchgate.net/publication/230937856_Optical_properties_of_graphene article (Optical properties of graphene) I found out the frequency is expressed in Kelvins. Could you help me with it - how did the author do this unit transformation? Thanks in advance!
  5. F

    Thin film interference - why thin, exactly?

    Hi, in every explanation of thin film interference I came across, little or nothing is said as to why the layer of transparent material creating the effect should be thin. What would go wrong if that is not the case? I'm asking because it seems to me that, in principle, the mathematic...
  6. J

    Light travels only in one direction material?

    I would like to know if their are any materials that would allow light to pass in only one direction, In electricity we have diode, which will allow electricity to pass in only one direction, in optics how do we reflect light from one side and allow light from the other side to pass through?
  7. Samama Fahim

    Spectral Intensity as a Function of Wavelength in Blackbody Radiation

    A blackbody is also a perfect emitter giving off electromagnetic waves at all frequencies. A detector could measure the intensity of the radiation it receives through the prism. By moving the detector to different positions, you could measure the intensity of light as a function of color or...
  8. henry wang

    Other How active is the field of Optics in physics and industry?

    I am a second year Physics student, and I have a summer research opportunity on Optics (for which the topic is uncertain). The topic will probably be related to Imaging in biological systems, Analogue computation using light and, Light scattering in correlated systems, as they are the topic of...
  9. qnach

    Classical Finding the Right Optics Book: Faraday Rotator

    Which book (on optics) can I find talking about Faraday rotator?
  10. S

    A Squeezed Light & NonLinear Optics

    We're hearing things in the news these days about Squeezed Light, and how it can be used to improve everything from LIGO detectors, to positional sensors, to Quantum Computing. What is Squeezed Light, what useful applications is it being investigated for, and how does it provide this extra...
  11. heavystray

    Invisibility cloaking using 4 lenses

    Hello, So, here's an article about invisibility cloaking http://www.businessinsider.my/how-to-make-a-rochester-invisibility-cloak-2014-9/?r=US&IR=T#ruDbxWBJYWXsXcyW.97 What I don't understand is how's the object between the lenses is cloaked. Is it because the rays are focused to a point...
  12. J

    Conservation of energy in refraction

    Hello, This has been bugging me for some time now, so I would be interested to see what I have been missing so far. Imagine a single ray of light (made up of many photons) hitting a perfectly non-absorbing (for this wavelength of light) spherical dielectric object, which has finite mass. The...
  13. A

    Backing-out luminosity togo from lumens to radiant flux in W

    Hi. Has anyone already done the work to back out the standard luminosity function so I can go from lumens at a particular wavelength to radiant flux in Watts? I have visible LED spec sheets with optical characteristics in lumens and I want to calculate the outputs in W. My NIR LED has specs in...
  14. nomadreid

    I Is the Indicatrix a Volume Chart or an Ellipsoid for Crystal Optical Properties?

    Trying to work through a paper which includes a discussion of the optical properties of crystal, and the author uses the term "indicatrix", at one point referring to it as a diagram, which makes sense, but another place referring to it as a "volume chart", which I haven't figured out. Could...
  15. JulienB

    Optics: dispersive power of diffraction grating

    Homework Statement Hi everybody! Here is the problem I am trying to solve: a) A source illuminates a grating in a spectroscopical element so that the principal maxima appear as thin bright bands (therefore the name "spectral lines"). Show that the angular width ##\Delta \theta## of such a...
  16. G

    I Steam punk, Field of view including the eye

    Sorry if I missed the answer in my search. I expect I'm not use the correct terms. I want to design a Galilean/opera glasses style steampunk monical mounted to my reading glasses. I already have a simple lens that I can swing in front of my one eye. When using commercial eyeglass mounted...
  17. Replusz

    Purpose of knife-edge in Schlieren (optics)

    I wanted to know what the purpose of the knife-edge in Schlieren optics is, but can't think of a suitable answer. Is it only to reduce the intensity of light equally? Thanks!
  18. S

    Crystal Optics -- Learning resources wanted....

    What are some good resources : books, websites, etc to understand crystal optics? I am a graduate student and I want to start with the basics.
  19. K

    A How to calculate the Wigner function for an entangled state

    I'm trying to calculate a Wigner Function of an entangled state, and I'm not quite sure how to proceed. I have created this state by sending in vacuum and a squeezed state into a 50/50 BS, where the output state has a density operator: $$\rho_{34}=S_{3}S_{4}S_{34}|00\rangle_{34}\langle...
  20. S

    Possible Wavelength Difference Between Two Rays Passing Through a Prism?

    Homework Statement The two rays shown below, a and b, have different wavelengths. They travel through the glass prism as shown; 1) is this possible? 2) If this is possible, which has the longer wavelength, ray a or ray b? [see attached figure] Homework Equations λ = λi/n critical angle =...
  21. JulienB

    Interpreting a system matrix (optics)

    Homework Statement Hi everybody! While doing some homework for school, I realized that I still struggle to get what are the elements of an optical system matrix referring to. Here is the problem: An optical tube with length ##L=50##cm has at one end a convex lens (##D=2##) and at the other...
  22. K

    I What is the boundary surface of a collimator?

    Hi everybody, I’m trying to calculate the shape of a boundary line f(x) between two mediums that collimates rays from a point light source. This requires the rays to hit the boundary line under a certain angle, so I calculated the slope m(φ) of the boundary line for a ray with polar angle φ (φ...
  23. Alvis

    Prove n1<N<n2 for effective index N....

    Homework Statement Prove for effective index N that n1<N<n2. Homework Equations [/B] N=n1sin(theta) TIR is theta>thetacritical snells law-n1sin(theta)=n2sin(theta2)The Attempt at a Solution I know why N is strictly less than n1 since sin(theta) goes from 0 to 1 and if its at 1 theta has to...
  24. K

    What are the unanswered questions in materials science and high energy physics?

    Hi, I love learning, and from time to time I run into questions that google, local education institutes, and general information hunting at the library comes up fruitless. So to you physics forum I turn! About me - Father, husband, geek, techie, cancer survivor x2, retired soldier/IT...
  25. CaptainJonathanNorth

    What is the Role of the 'Unofficial Chief of Naval Innovation' in the US Navy?

    Hello, I used to hang out here many years ago, like 30 years ago. I am have some definite ideas about physics that might or might not be important. I have seen and done some amazing things in terms of science in the US Navy. I am, and have been for some 30 years, the "Unofficial Chief of...
  26. G

    Is laser light polarised? In which direction?

    Hello. I want to know about the polarisation of lasers and I've been reading basically two kinds of answers for the question 'Is laser light polarised?' The first one is 'yes' and the second one 'not necessarily'. Let's consider a gaussian laser. Ideally its light is monochromatic and coherent...
  27. Y

    What will happen if angle of incidence on a glass slab is 0?

    I have a conceptual doubt. pl help me clarify it: What will happen if angle of incidence on a glass slab is 0? will refraction take place, or reflection, or both?
  28. G

    Calculate the focal length of a planoconvex lens?

    Homework Statement Calculate the focal length of a planoconvex lens that produces a real image 2.5 times as big as the object if the object is 2.5 cm from the lens? Homework Equations The only one I can think of is 1/f = 1/v + 1/u The Attempt at a Solution [/B] My 'attempt' is 1/f = 1/62.5...
  29. P

    Understanding Far Points and Lens Power in Correcting Myopia

    Homework Statement While carrying contact lenses of D=-2.00 diopters, a nearsighted person takes a vision test and finds that his/her far point is 10.0m a) what is the person's far point without contact lenses? b) what lens power is required to correct the myopia fully? Homework Equations 1/f...
  30. R

    What is the Optical Table Simulator and how can it be used?

    Hi All, My name is Radek Strugalski and I am creator of an Optical Table Simulator, a 2D precise ray tracing engine written in Silverlight 5. It can be used for educational purposes, experimentation or jus fun. It's completely free and so far no plans to spoil it with ads. :) I saw that some...
  31. B

    I Quarter-wave plates and Half-wave plates

    Hi, I am aware that quater-wave plates create a phase shifts of λ / 4 between the fast and slow transmission axis. My question is what happens if we place two quater-wave plates in series so that there is 0 degrees between the fast transmission axis and how would result change if they where...
  32. Hamal_Arietis

    Classical Are There Good Thermodynamics and Optics Books for Physics Students?

    Hi I'm a physics student in university, I want to find a book about general thermodynamics which has great and interesting problems. Includes a bit of statistical physics and molecular physics. And a book has theory and problems about optics, wave optics and geometrical optics. Thanks for helping
  33. O

    Strange results with transfer matrix (Optics)

    Hi everyone, I'm trying to study reflection on the rear side of an optical device. I wrote a transfer-matrix code in MATLAB to compute the reflectance. I checked my code by comparing some basic cases with other kind of optical simulations (FTDT with Lumerical). When the incident medium is Air...
  34. Abdul Wali

    Regarding Fiber Optics and Coaxial Cable

    Hi, "limitations/Constraints of Fiber Optics and Coaxial cable for average home user ?"
  35. D

    Collimating image from an LCD display

    I have an LCD display I'd like to use in a collimated HUD display, however it seems that I can't get the light (image) from it to collimate properly. I'm trying to use a lens with the focal distance of 4.5 cm. When I place the display 4.5 cm away from the lens' center I expected to achieve the...
  36. SteveeGeorge

    Optics - Re-aligning P Polarization with Brewster Windows

    Hi all, I have a problem, and in need of some help. I am an optical engineer, currently designing an attentuator for near infrared lasers (10.6μm). The attenuator consists of two enhanced ZnSe Brewster windows that rotate in opposite directions and different angles to exactly re-align...
  37. TheCapacitor

    Optical DIY Telescope theory and questions

    I'm confused about the theory of the telescope I am making. My questions are: 1. Magnification - according to my image we should see magnification because the image we see is the image formed by the continuation of the dotted lines. Is that true? 2. Why do we need lenses with different size? If...
  38. SteveeGeorge

    (Introduction) Steven George - Optical Engineer

    Hi all, I'd like to introduce myself. My name is Steven George, 22 years of age and from London, UK. I am a recent masters graduate of physics (July 2016), achieving a 1st class honors. Quickly after graduating, I found employment as an optical engineer for a company that specializes in laser...
  39. H

    Non-Linear optics vs The 2nd Law of Thermodynamics

    Hi, rank newbie here, with my first post. This one is something I figure every first year student comes up with at some point, but I don't know enough keywords to Search for an answer. (I'm not a student except in the category "of life": this isn't assigned homework) I figger, using a bit of...
  40. E

    How Can Light Transmission and Reflection Exceed 100% in an Optics Experiment?

    You have a glass (or plastic) dish (like a small transparent dish). You shine light onto its flat surface. Your lab partner discovers that 55% of the light has been transmitted, 55% is reflected. What is the absorbance of the dish (not in the log scale, just as a regular %age)? State a...
  41. E

    Why water looks transparent while spray looks white?

    The water looks transparent, but when the water hit the stone, it looks as if it turns white? Why?
  42. TheCapacitor

    Why image is blurry or focused with convex lenses?

    Homework Statement I have a few fundamental questions in optics about the focus and blurry images. Each textbook says that according to this picture the object image is the same. 1) If we move the screen to point further then the image will be blurry. What causes it to be blurry? 2) Why do...
  43. TheCapacitor

    Finding focal point of concave lens using concave and convex

    Homework Statement [/B] I was doing http://stao.ca/VLresources/sci-tie-data/lessons/1400_1499/DivergingLensExperimentDeta.pdf experiment. Let's look at this image: Suppose we get the imaginary object at dv by convergence lens. And this object is like a real object for the concave lens. Then...
  44. E

    I Horizontal Noise Stripes in an Image

    What are the possible causes of the horizontal noise stripes in this image: http://dsp.stackexchange.com/questions/20061/removing-periodic-noise-from-image-using-fourier-transform I'm currently studying on these kinds of noise, and how to eliminate them. Can these be caused by diffraction...
  45. E

    Resolution when not diffraction limited

    Does anyone know if there is a way to determine the resolution of an optics system that is NOT diffraction limited. I know you can calculate the resolution of a diffraction limited system using the Rayleigh criterion, but that assumes the system is diffraction limited. Is there some way using...
  46. E

    A Reversed Spot Diagram: Image & Point Source Effects

    If you have an optics system where you know the spot diagram of the image at on imaging on one plain and projecting onto another. Where you know the spot size for a point source at a given distance from the centre of the field. Now if you reverse the system where the imaging plain now becomes...
  47. M

    Stargazing Telescope Design: Calculating Total Distance from Primary Mirror to Eyepiece

    I am currently in the middle of constructing a Newtonian reflecting telescope and I had a question. The focal length for my primary mirror is 1500mm and 3mm for my eyepiece. My question relates to the path of the light inside the tube of a telescope. I understand that in a Newtonian reflector...
  48. Chandler

    Other Intermediate Optics (including nonlinear optics)?

    Hey everyone. I'm currently in a new research lab that focuses on optics. One thing I'm currently tasked with is handling the femtosecond laser we have. However, to do this, I need a stronger background in optics than I currently have (which is a few years of undergrad optics, some quantum...
  49. MMircky

    Studying What Are the Best Resources for Understanding Nonlinear Optics?

    I am currently an undergrad studying physics and am doing research on PPLN and nonlinear optics. I have a basic understanding of the math involved with my research, but would like to know more on nonlinear optics and why these materials behave the way they do. I am currently reading...
  50. J

    Image Distance with two concave lenses

    Homework Statement An object 1.25 cm tall is placed 100 cm in front of a convex lens with a focal length of magnitude 50 cm. A concave lens with a focal length of magnitude 20 cm is placed 90 cm beyond the first lens. Where is the final image located? Homework Equations (1/s)+(1/s')=1/f s=...
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