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. J

    I Minimum light bulb wattage for solar simulator

    I am trying to design a simple homemade PV solar simulator. I have picked metal-halide lamps as my light source. If the PV panel has an area of 1m^2 and I wanted to achieve spatial uniformity across the irradiated surface with an irradiance of 1000 W/m^2, how do I go about selecting what...
  2. rogdal

    I Hologram recording on photorefractive material

    Good morning, I am developing an experiment on how to study the kinetics of etching/erasure of holographic lattices in a photorefractive material and I have some doubts about the procedure to follow. I have a single-mode He-Ne laser with monochromatic light of wavelength 632.8 nm and the...
  3. H

    I Plane wave decomposition method in scalar optics

    Suppose an optical scalar wave traveling in Z direction. Using the diffraction theory of Fourier Optics, we can predict its new distribution after a distance Z. The core idea of Fourier Optics is to decompose a scalar wave into plane waves traveling in different directions. But this...
  4. Jan Berkhout

    Calculate the best angle for maximum light dispersion through a medium

    I first thought that the angle would have to be maximum when it is closest to the critical angle for total internal reflection. From my lectures the equation for the critical angle is ##\theta _1>\ sin ^{-1} \left( \frac {n_2} {n_1} \right),## so as ##n_2 = 1##, we have ##\theta _1=\sin...
  5. Z

    I Scattering and non-imaging optics

    I have seen the term "conventional scattering lens" being used (see https://arxiv.org/pdf/2112.08144) and I was wondering whether the term scattering lens is accurate? I always envisioned a lens as a refractive element, and wondering if the reference means refracting rather than scattering...
  6. OliverFroelich

    A Iphone Reflection has a pattern

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  7. S

    Solid State Researching Gold Thin Films: Electrical & Optical Properties

    Hi Physics folks,I am currently collecting resources for my senior seminar project at my university and would like to ask if anyone has any good references for gold thin films. I am planning on focusing primarily on the electrical and optical properties of gold thin films. I appreciate any...
  8. Aymangh994

    I Using simple lenses to image AFM Probes

    Hello, Using a CCD camera and simple lenses, the probe of the cantilever and its surroundings are to be imaged. Since the cantilever is 50 um wide and some of the surroundings are to be imaged, the optimal image magnification is from 4 to 8. I therefore used a convex lens with a focal length of...
  9. KayT256

    B What does "1 diopter of astigmatism" mean?

    The measurement for astigmatism is diopter. But what does 1 diopter of astigmatism mean? Thanks a lot if you help me figure this out!
  10. LCSphysicist

    Courses Quantum optics for graduate students

    I have just finished my course on electromagnetism. Due to my performance, the professor has contact me for congratulations and asking, if i want, to join his quantum optics course for graduate students. Even so i think it is interesting to follow the advice, i am a little afraid if this...
  11. Andy1011

    Nonreflective Film: Solving the Ref. Index Problem

    I thought of sandwiching the coating between lens sufaces and then applied the condition of minimum which gave a thickness of lambda/2*ref. Index and I got totally stuck at the ref. Index.
  12. L

    Image position and magnification for underwater spherical lens

    Using the data given and recalling that in this configuration ##R<0## I get: ##\frac{1.33}{0.5}+\frac{1.5}{q}=\frac{1.5-1.33}{-0.2}\Rightarrow q\approx -0.427 m=-42.7 cm## so the image is virtual and is ##42.7\ cm## to the left of vertex ##V##. The magnification is ##M=\frac{n_1 q}{n_2...
  13. N

    I Lens angle of coverage/image circle

    Hello, I was wondering what parameters determine the angle of coverage/size of the image circle of a lens. For example, for a fixed focal length, aperture and flange focal distance of a camera, what can a lens designer do to change the size of the image circle. I'd also like to know how the...
  14. jerry222

    Interference of light in thin films

    Phase difference is $\phi=\frac{2pi}{\lambda}* \Delta+\pi$ Phase difference, max: $\Delta \phi=2pim=\frac{2pi}{\lamda_{max}}*2nd$ Phase difference, max: $\Delta \phi=2pim=\frac{2pi}{\lamda_{min}}*2nd+pi$ Flim thickness: $d=100nm$ Set the equations equal to each other i got a d=-100nm which...
  15. A

    Procedure to express radiation intensity of an LED in watts/cm^2

    I am calculating Responsivity of a pn junction photodiode (a.k.a the target) by irradiating radiation from LED sources. For this purpose, i have two LEDs, one UV and another green LED. Note that LEDs are placed close to the target.UV LED : Manufacturer has given total radiant power to be 20mW...
  16. ynyin

    I Rotating Polarization with Optics: Exploring the Principle

    In optics experiments, I often see the following optics configuration to rotate the polarization of an incident linearly-polarized laser beam. The final reflected beam has its polarization rotated by 90 degrees. My question is: 1) Between the quarter plate and the mirror( reflecting surface)...
  17. E

    Engineering Photonics / Fibre Optics - (Supermodes, PBGFs, Coupling)

    Hi, Looking for a good photonics / fibre optics textbook that covers the field, while also addressing said topics in the title. Thank you!
  18. rishurboi

    I Applications of Virtual objects

    I've heard virtual objects are used in cinema halls I'm not sure of what that means, can someone explain this to me please? And btw by virtual object i mean when diverging rays from real object passes through a convex lens, the rays will converging and if you'll place a plane mirror infront of...
  19. tomceka

    Geometrical optics: using Snell's law, find the depth of the pool

    α=30°; l=0.5 m; n1=1; n2=1.33 α+β=90°, so β=90°-30°=60°. Using Snell's law: sinβ/sinγ = n2/n1 sinγ≈0.651 γ≈41°. β=γ+θ (vertical angles) θ=60°-41°=19° tan(θ+β)=l/h h=l/tan(θ+γ) h=0.5/(tan(19+41))≈0.289 m
  20. F

    Finding Total Number of Optical Field Modes for Visible Light

    ρ_kdk = k^2/π^2 dk is the density of field modes (what we are trying to solve for here), and as ρ_kdk = ρ_λdλ, and k=2π/λ, we can rearrange this to get ρ_λdλ = 8π/λ^4dλ This is where my confusion lies. I am not sure what to do next. I know this equation physically means the number of modes per...
  21. L

    A problem involving thin film interference

    I know that every time that light goes from traveling through a medium with lower refractive index to one with a higher refractive index the reflected light undergoes a ##\frac{\lambda}{2}## phase change. Since this happens both at the air-plate and plate-glass interfaces we have that the phase...
  22. samy4408

    I What does "upright" mean in geometric optics?

    if someone want to explain to me what is an upright image ? , and what are the other adjectives to define an image in geometric optics and their meaning , Thanks .
  23. A

    Exploring the Intersection of Chemical Engineering and Optics: A Ph.D. Journey

    I am doing a Ph.D. in optics in the UK. Nonetheless, my core formation is as a chemical engineer. That is why I lack some knowledge about optics that I am actively going to look for answers and figure out my unknowns in this forum.
  24. Father_Ing

    Could the Image from the First Mirror Be Real for the Second Mirror?

    I'm currently confused in determining whether an image formed by the 1st mirror (the left one) is a real or virtual object for the 2nd mirror. Here is the solution manual: This is what I have in my mind: Since the object is located between the focus and radius point of the first mirror, the...
  25. EBINESH

    I Help Needed for Lens Selection for Fiber optics

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  26. C

    A Absorption and emission spectrum in quantum optics

    The emission spectrum or resonance fluorescence for a quantum dot, atom or defect center are discussed in many quantum optics textbook, for example see "Quantum Optics" by Marlan O. Scully and M. Suhail Zubairy Chapter 10 , "Quantum Optics" by D. F. Walls and Gerard J. Milburn Chapter 10 and...
  27. B

    Correct Angle for FSW in Fabry-Perot Interferometer

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  28. yglo98

    Optics. A laser beam is refracted in a piece of glass.

    A red laser with the diameter of 3mm is directed towards a piece of glass. It has the effect, P of 1mW. The angle of incidence is 90 degrees. The glass has refraction index n2= 1,5 and thickness 2 cm. Its front side is convex with a convergence radius,R, of 11 cm. The back side is plane. Whats...
  29. warhammer

    Intensity Distribution of Superposition of 2 Waves

    We assume incident waves to be: y(1)=y(o)sin(wt) y(2)=3y(o)sin(wt+Φ) As Intensity~(Amplitude)^2 We get y(2)=3y(1) This gives us I(2)=9I(1) We assume I(1)=I(o) & I(2)=9I(o) Resultant Wave Intensity I=I(1)+I(2) +2√(I(1)*I(2))*cosΦ ----> I(o) + 9I(o) + 6I(o)cosΦ (We can take cos of this...
  30. T

    A Reflectivity with gradient in refractive index

    Hey all. Was wondering if anyone knew how I would go about determining the amount of reflectance that occurs when there is a gradual change in the refractive index. For example, if I have a material in air whose refractive index begins at e_r=1 (i.e. it matches the refractive index of the air)...
  31. warhammer

    I On 'A Quarter Waveplate (QWP) rotated between 2 Polarisers'

    While going through the book 'Problems & Solutions in Optics and Photonics' I was having difficulty in understanding a question & have some issues about my own conceptual know-how in this regard. The Question is: A quarter-wave plate is rotated between two crossed polaroids. If an unpolarised...
  32. theycallmevirgo

    Simple(?) parabolic dish design question

    I want to use this to design a parabolic (optical) mirror; The problem is that in my application I need both D and f to be a parameter, but I need to specify f only as a perpendicular distance from D. In other words, I need to specify some f_2=f-d, and calculate d. I can't seem to come up with...
  33. warhammer

    Question on Resolving Power of Diffraction Grating

    I have doubts about my work for the second part of the question, where I am asked if resolution will be possible or not. For the first part, I calculated No. of lines N=6.43*10^2 lines/cm For the second part, I have attached below a snapshot of my neatly written work. I request a PF member to...
  34. L

    Medical Regeneration of optics nerves -- How?

    https://www.science.org/content/article/researchers-restore-lost-sight-mice-offering-clues-reversing-aging I understand that they used 3 of 4 Yamanaka factors to reverse the epigenetic profile of certain cells in the optic nerve, but what caused an apparent regeneration of the nerve? I can...
  35. fluidistic

    I How to "think" of a polarizer in matrix representation?

    From what I remember of my optics course, any element such as a lens (be it thick or thin), can be represented by a matrix. So they are sort of operators, and it is then easy to see how they transform an incident ray, since we can apply the matrix to the electric field vector and see how it gets...
  36. warhammer

    I Correct Formula for "No Fringe Condition" (Michelson Interferometer)

    In two different textbooks, there are two different formulas with different derivation styles for the "No Fringe Formation" Condition. In approach (a), they use an amalgamation of bright and dark for 2 wavelengths having very minute difference in the following manner: 2dcostheta=n*λ(1)...
  37. J

    I Using Diffraction (i.e., Fresnel Zone Plate) to defocus/diverge light

    I am wondering if it is possible to use principals of diffraction to cause a collimated beam of light (laser) to become divergent. I see that zone plates are most always used for focusing the light from a source, unless they are used in reverse. This is why zone plates are seemingly always...
  38. rinalai

    [Optics] Questions on the Stokes shift

    Here is my answer to this question: Stokes shift is the difference in wavelength between positions of the band maxima of the excitation and emission spectra of the same electronic transition. When Stokes shift is large, it means there is more energy loss, which is not favorable regarding...
  39. rinalai

    [Optics] Compound microscope (homework quiz)

    R = 1.22*700nm/(1.3+0.95) ≈ 380nm
  40. yucheng

    Astronomy Technical, physical text on (astro)photography & telescopes?

    It appears that many texts on astrophotography and telescopes for amateurs tend to avoid mathematical formulas, as such, they are of little use to do some practical calculations. What I am interested in is: Magnification Image scale Focal length Focal plane and sensor plane! (CCDs!) Focal-ratio...
  41. G

    How do dark spot and tiny hole filters affect Fourier optics images?

    I was assigned an experiment of Fouriers optics where I have to use different Filters. One of them was the dark spot and the tiny hole. As of my understanding, for tiny hole, we cut off all high-frequency light related to diffraction and refraction, thus using only the low freuency part of the...
  42. J

    A How to calculate the temperature change of a laser-irradiated material

    I am looking to approximately calculate the temperature change of a sample that was exposed to a laser pulse. Experimentally, we know the optical absorption, reflection, and transmission, as well as the source parameters for our laser system. I realize that I will have to make approximations...
  43. Marioweee

    What is the focal point of a lens in a geometrical optics problem?

    I have recently started with geometric optics and I do not quite understand what this problem asks of me. According to the statement, the focal point of the lens would be -25.5cm, right? That is, it is only a problem of concepts where it is not necessary to take into account the radii of the...
  44. 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
  45. Yukatto

    Engineering Recommended book for Optical Engineering graduate

    I am a recent Optical Engineering graduate, It's easy to forget about concepts that I learned, so I would like to have a book to that can help me while preparing for job interviews, a book to help me remember the most important concept in Optics and Optical Engineering. Can anybody recommend...
  46. Ebi Rogha

    I Can a single photon be reflected by a mirror?

    If the answer is Yes, then I would ask, if the mirror absorbs a portion of the energy of the photon, so the photon should simply stop existing because we cannot have a smaller package of light than a photon. If the answer is No, then I would ask why a beam of light (which is made of a big...
  47. B

    Solid angle in an optics problem (artificial irradiance of the Earth)

    The actual problem can be found as #2 on this link: https://ocw.mit.edu/courses/mechanical-engineering/2-71-optics-spring-2009/assignments/MIT2_71S09_ups1.pdf I rewrote the problem above with the solar irradiance data that they give. My interpretation is of a square 1 m x 1 m plane sitting...
  48. B

    Did I Calculate the Correct Derivative to Validate Faraday's Law?

    I've calculated the negative time derivative of B(r, t) as: $$-\frac{\partial B}{\partial t} = k~\text x~E_0~\text{sin}(k \cdot r - \omega t + \phi)$$ The cross product can be easily expanded, I'd just rather not do the LaTeX for if I can avoid it. The Curl of the electric field...
  49. B

    Multivariable Calculus proof for Optics

    Part A) For part A I forgo breaking down the identity into it's component x, y, and z parts, and just take the r derivative treating r' as a constant vector. This seems to give the right answer, but to be entirely honest I'm not sure how I'd go about doing this component by component. I figure...
  50. stephen8686

    Courses Quantum Optics, Feeling Overwhelmed and Underprepared

    I am an undergraduate at a fairly well known research university. I have taken undergraduate QM 1, QM 2, and the graduate course on Quantum Optics. I got As in all of them and found them not very difficult. Now I am in a research group researching superradiance. I do not feel like any of my...
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