What is Optical: Definition and 696 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. F

    Optical signal and encryption

    What is the difference between encrypting an electrical signal and converting it to optics; & converting the signal to optics and then encrypting it? (Any of the symmetric or asymmetric encryption techniques).
  2. J

    Understanding Optical Isomers: Identifying Correct Answers for Problem 1

    1. Homework Statement I thought G was the answer for part i) but it should be J, why? I can roughly see the pattern- the RHS of G is rotated 120 ° and J is formed, but why isn't G or H the answer? How to see if any two structures are optical isomers of each other? Does mirror images come into...
  3. sounouhid

    Optical band gap of a cobalt ferrite

    Hi everyone How can I determine the optical band gap of a cobalt ferrite film deposited on a glass substrate using its absorption, transmittance and diffuse reflectance spectrum (knowing that I don't know the thickness of this film)
  4. D

    Optical Probe Clarity: Examining Power Loss vs. Beam Spot

    I work in a lab that uses laser probes to test for vibration and other data, currently the lab techs hook up the probe to a laser source and check to see how bright and clear the beam spot is. I have been working on having a signal power budget created for each probe using a laser source and...
  5. chikou24i

    A Acoustic and optical branches in phonons dispersion curves

    What is the physical meaning of acoustic and optical branches in phonons dispersion curves ?
  6. G

    Where is the information in an optical fiber?

    Hi. I know how optical fibers work but where is the information in the light signal passing through it? Which characteristics of the electric field carry it? I begun to think about it because I was intrigued if they took into account things like the Goos-Hänchen shift or angular deviations in...
  7. Tazerfish

    Strange Optical Phenomenon (diffraction or something else?)

    First of all i will post a picture of it ... you can find it ... somewhere sorry this is my first post :I I photographed our television with the flash on in order to recreate a strange patter i saw when looking at the suns reflection in the screen.(with my eyes it's not just the camera) You can...
  8. Vajhe

    Computational Resources for learning about Optical Beam Propagation Method (BPM)

    Hi, I'm a physicist intern that has some problems with Optics simulations; I'm very interested in doing some Beam Propagation Method (BPM) simulation, but the information online is not that good for begginers in the area. Can anyone advise me on books, journals or such that might help me learn...
  9. L

    A Difference between an optical and an acoustic phonon

    Hello friends. My question consists two parts, 1-What is the difference between an optical and an acoustic phonon? 1-What are the conditions by which we can decide the type of phonon i.e optical or acoustic phonon ? Hope to get the reply soon.
  10. G

    Total internal reflection, refractive index, optical fibres

    How does the claddibg with lower refractive index reduce the light loss from the core? Thank you.
  11. Soheyb BENYAHIA

    What Are the Best Software Options for Simulating Interferometric Systems?

    Hey, I'm trying to simulate an interferometric system for distance measurements, but I can't really find helpful software for that. Currently, I'm using OptiSystem 14, but it's really hard to do it since it doesn't contain some components like the mirrors. So, I will be grateful if I get any...
  12. henil

    Optical Tweezers: Preparing Samples for RBC Trapping

    I am currently working on project for trapping RBC's using optical tweezers but i think i am making a mistake in preparing the sample. Can anyone provide an appropriate sample preparing method ?
  13. Raptor112

    A Optical Bistability and the Jaynes-Cummings Model

    I understand that otical bistability only occurs in a specific parameter regime defined by the bimodial leaf, but I have read that bistability originates from highly non linear dynamics of the system. As we are dealing with a qubit in a cavity that is being driven so things become non-trivial...
  14. D

    Optical instruments: Microscope and Telescope

    What are the different formulas for the calculation of magnifying power of a microscope and a telescope? And how would we use the sign conventions in them?
  15. M

    Optical and electrical bandwidth "outside" air

    My questions is about the conversion of a range of wavelengths in Hz, such as for an optical filter, in a medium different from air. Since the refractive index n is higher than 1, (let's say n=1.5) and than the value of c is almost 2x108 m/s, also the equation in the link below has to be...
  16. P

    Optical physics and frame of reference....

    What kind of frame of reference do I have to choose when I'm studiyng lens and mirrors? As far as I know you consider positive the direction where the rays are real and negative the one where the rays are virtual, is that always true? Why can't we study a problem of optics choosing a frame of...
  17. R

    Suggestion for Research Project on Optical Nanoantenna

    Hello, I'm currently a Senior year EE student in a South Asian country. We are planning to do a research project on Optical Nanoantennas. We are still learning and are not very familiar with the theoretical stuff, we only have the knowledge of junior year undergrads (took EM Fields and Wave...
  18. L

    Overlaying optical field with Zernike aberration

    Hi there, optical aberrations can be expressed by Zernike polynomials Vmn(ρ,θ). Now, for my simulations i am using software that takes 4 inputs for creating aberrations onto an optical flat: m,n,R,A m,n are the Zernike orders which is perfectly clear. For R,A the manual says: R: the radius A...
  19. Charles Link

    Understanding Non-Linear Optical Interference: The Role of Energy Equations"

    This post is related to a posting I did a couple of days ago, but I will go into more detail on this one, and it should be more easy to see the concept that is presented. A number of years ago, I was explaining interference concepts to a physics Ph.D. who had very little background in...
  20. E

    Field frequency and angle of incidence in optical waveguides

    Hello! In this previous post, most replies point out that it is not possible to predict the angle of refraction (and so the frequency) at a certain interface, given the wavelength of the original signal. In particular, But when dealing with optical waveguides, it seems to be different. I am...
  21. T

    What is a floquet (optical) sideband?

    In literature, I read:"(exposed in a beam of light) in floquet theory, the quasi-static eigenvalue spectrum at finite driving field A shows copies of the original bands shifted by integer multiples of ##\Omega##, the so-called Floquet sidebands" I have read something about floquet theory and...
  22. Jhon Paul

    Transmittance of Cyclohexane for IR Radiation Through Quartz Viewport

    I am interested to use a pyrometer to measure the temperature of a graphite heater while it is being heated (upto 1200 degC). The heater is located inside a small chamber filled with liquid cyclohexane . For viewing purpose of the pyrometer the chamber is having a viewport of Quartz. The...
  23. B

    Optical lasers to photograph space

    We use lasers containing various elements in vacuums on Earth all the time. Is it possible to use lasers in the dirty vacuum of space to take pics and transmit at near the speed of light?
  24. D

    What is the formula for calculating the optical output power of an LED?

    Hi, i was doing a science project on LEDs, and i needed to calculate optical output power versus input electrical power to find relative wall plug efficiency. This is the only good formula i found Optical output power of LED (watts) =Nlinearfactor × Voltage drop across resistor (volts) Pout = N...
  25. A

    How optical axis is related to dielectric tensor?

    I want to know the relationship between the optical axis direction of a crystal and the dielectric constants in different directions in an anisotropic material.
  26. Anton Alice

    Dopplershift, using changing optical length

    Hello, again a simple question: consider a mirror, with a transparent layer (index of refraction n) of certain thickness on it. If a ray is reflected by the mirror, while the mirror is moved normal to the plane, then one could observe a dopplershift. But what happens if the mirror is fixed...
  27. Anton Alice

    Time dependent optical path length vs coherence

    Hello, I have a simple question. Suppose a perfect point source in front of a mirror. The virtual image of the point source acts like a second point source. Now let's look at the interference of the direct point source light and the virtual point source, at some position. Since the path...
  28. F

    Help to find a simple setup for optical surface topography

    Hi everyone. I'm looking for some help from someone expert in optics to create an inteferometry based setup to map the surface of a small object. This is for a small lab project so I'm not looking for a really complex setup, I just need something simple that can be built in a short amount of...
  29. E

    Cross Phase Modulation in Optical Fibers (Fiber Optics)

    Hello everyone. I have been practicing for my exam in fiber optics, and stumbled upon the following question: We have a transmission system with 3 channels, composed of a single mode fiber and a dispersion compensation fiber. Specifications are given for each. We need to calculate the channel's...
  30. Jeprox

    Light, wavelength and optical filters

    Hi, I have read from previous topic regarding color of light vs wavelength. It is a bit confusing for on my self as I do not have any background on this. Hopefully someone could chime in and educate myself. Here it goes, it has been lingering in my head that the color of light emitted by a...
  31. chikou24i

    Optical microscopy image analysis

    How one can analyse an image of a solid material obtained with an optical microscope ?
  32. pioneerboy

    Engineering From mechanical to optical engineering

    Hi there, Is it easily possible to change to optical engineering for the MSc and being involved in big telescope constructions after getting a BSc degree in mechanical engineering? Lucius
  33. J

    Optical Model Analysis: Easy Prog. for Alpha-Particle & Heavy Ion Scat.

    I am working on a thesis, but new to programming. What is the best and easy to use program that I can use for the work: Measurement and analysis of elastic scattering of alpha–particle and light heavy ion scattering using nucleon-nucleon interaction
  34. B

    Optical simulations of gravitational effects

    I'm preparing a poster presentation on the following paper for a physics course: http://t.co/xiCLV7Y0ZH I do not understand how figure 4 tells us about the red/blue shift. Just from the deflections of the peaks of the airy beam, as well as the deformation, how are we able to infer that there is...
  35. B

    Optical Fourier Transform for Propagation

    Homework Statement The complex amplitudes of a monochromatic wave of wavelength ##\lambda## in the z=0 and z=d planes are f(x,y) and g(x,y), redprctively. Assume ##d=10^4 \lambda##, use harmonic analysis to determine g(x,y) in the following cases: (a) f(x,y)=1 ... (d) ##f(x,y)=cos^2(\pi y / 2...
  36. F

    Low-cost low threshold optical beam limiter?

    Do you guys know a low-cost low-threshold optical beam limiter, with cost somewhere ~$100. Or if you know certain method to fabricate such. I would be greatful if you could include links and/or references. I am still noob in photonics so I am only familiar with a beam limiter that blocks the...
  37. M

    Infrared Waves in Optical Fibres

    I was reading about a process called up-conversion mentioned in Robert Boyd's Non-Linear Optics. It is essentially a special case of sum frequency generation (in sum frequency generation, two waves of different frequencies are sent into the crystal, and out comes a wave with a frequency equal to...
  38. H

    Nd:YAG laser optical system setup

    Is there anyone who has experience in setting up optical system for exciting a sample using Q-switch mode of Nd:YAG laser? I am currently looking at the optical system which I did not setup (someone else did, but the person is absent and cannot contact). I have no background whatsoever in...
  39. S

    How can I write code for an optical touchscreen using infrared technology?

    Hello, I am looking into building a touch screen. I have been considering a capacitive touch screen but I am also interested in optical touchscreen using infrared like the ones one this link...
  40. JG1009

    Optical Pumping & Laser Wavelengths

    During optical pumping in a laser, is the wavelength of light that corresponds to the transition from the metastable state that yields the laser light removed? Otherwise, wouldn't a population inversion not be possible as these photons from the optical pumping would cause stimulated emission...
  41. R

    PT symmetry breaking in optical systems

    There are very results published about PT symmetry breaking in optical systems, with effects like anysotropical transmission resonance in waveguides. But if PT symmetry is broken in a optical system and CPT symmetry must always be respected, then what C symmetry is broken in a optical system?
  42. J

    How the Human Eye Works & Its Impact on Vision

    I can't understand how eye actually works. From what I understand when I look at 2 objects of the same size The object that is further is smaller in the final image because light rays reflected from it take smaller surface at the retina (Here B is smaller than A because rays take less surface at...
  43. S

    Optical microscopes and white light / laser light

    I have a few questions regarding an optical microscope and their white light sources... So white light generally first hits a diffuser, some kind of ground glass lens. What is the purpose of this? Then the light goes through a field diaphragm, which we can open and close. I have heard that...
  44. C

    Optical Stimulated Luminescence

    In a measurement of an OSL spectrum the wavelength of the stimulation source is always higher than the wavelength of the emission of the material. Is this due to the fact that at lower wavelengths one can no longer distinguish between stimulation and emission light? Can electron traps be...
  45. M

    Upper Level Math for Optical Physics/Engineering

    I am entering my final year as a physics/math double major undergrad and have hopes to continue onto a PhD program where I can do optics research, either through a physics or ECE department. That being said, my interests lie in experimental work rather than computational or theoretical, but I...
  46. J

    Possibility of optical absorption by defect level in bandgap

    Hi, I have a tricky question regards the absorption of photons by semiconductor. Say I got a piece of semiconductor with Eg=4eV. Inside the bandgap, there are two defect levels, and each of them have a trapped electron. One of the defect has the energy level that is 1eV below conduction...
  47. BUI TUAN KHAI

    Optical Properties of scintillator detector

    Dear all, I would like to study more about the optical properties of scintillator detector in nuclear physics experiment. Is there any good reference for this? If the reference is discussed deeply in solid-state-physics, that is really nice. Actually, I am attending a "optical properties of...
  48. C

    Nuclear fusion using miniature optical particle accelerator?

    Greetings I am not a physicist myself, so please forgive me, if my question/proposition will sound naif. I noticed some articles about accelerating electrons using laser and glass gratings: http://phys.org/news/2013-09-chip.html http://phys.org/news/2013-10-particles-compact-particle.html I...
  49. N

    Verdet Constant and optical pumping

    While studying Faraday rotation (linear magneto-optic rotation) I came across a fact that faraday rotation can be enhanced. Verdet constant which depends on the wavelength can be enhanced as change in refractive index with change in wavelength is maximum near resonant light. Now if the incident...
  50. P

    What is an optical straight line (photon path)?

    Can anyone explain why a photon seems to travel in a perfectly straight 3D line over unimaginable distances? What exactly defines a straight-line? The concept appeals to Cartesian coordinate space. Is there any way to quantify the straightness of a photon path? Or, does the path taken by...
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