Optics is the study of light, and its interaction with matter. It includes topics such as imaging systems, fiber optics, lasers, quantum optics, and more.

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Why does light diffract only through slits?

We can see diffraction of light if we allow light to pass through a slit, but why doesn't diffraction occur if we obstruct light using some other object, say a block? Why are shadows formed? Why ...
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0answers
242 views

What is the physical meaning of magnifying power of a telescope?

So the following question was given in the JEE Mains 2016 conducted throughout India on 3rd April. An observer looks at a distant tree of height 10 m with a telescope of magnifying power of 20. To ...
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4answers
2k views

What causes multiple colored patches on a wet road?

I was going to school (after a rainy hour) when I saw some patches of shiny colours lying on road. Some small children surrounded that area and thought that it's a rainbow falling on the Earth. (For ...
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1answer
38 views

What causes damage to interference filters?

I am currently working on a UV detector meant to be mounted on a CubeSat satellite. To select the bandwidth, I consider using an interference filter placed between the detector and the source. ...
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1answer
50 views

What determines laser frequency?

I am studying Lasers and frequency combs - and am not quite understanding something. I understand the working principle of a laser, and thought the Laser output frequency is just the energy gap ...
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1answer
22 views

Thermal imaging

If we have thermal imaging camera and the sound is wave is produced and propagates in hot air can we see the electromagnetic emission of molecules producing pressure packets of sound wave?
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2answers
274 views

Luminance from multiple light sources

I have a LED diode: Given Luminance intensity [I] of $1.85$ cd. I want to have Luminance [B] from the light source of $75 \ {\rm cd/m^2}$. From $B=I/S$, where S is light source plane area, I get ...
3
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1answer
36 views

Femtosecond photography

My question regards comments made around the 9:23 minute mark in Ramesh Raskar's TED talk, "Imaging at a trillion frames per second". At this point in the talk, an image shows "light ripples" that ...
4
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1answer
199 views

Diffraction and $k$-space

Regarding diffraction I am a little bit lost reading about reciprocal space and the space of $k$'s. As I understand it the Fourier relationship between a wavepacket $\Psi(\vec r,t)$ and the complex ...
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2answers
135 views

Spatial coherence of SLED light (width of active region?)

As far as I know, super-luminescent diodes (a.k.a. SLEDs) have a very similar structure to laser diodes, except that the front faces of the active region are tilted to prevent the sort of reflections ...
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0answers
32 views

Splitting an image in a lens into two sources?

Is it possible to project an image of light that passes into a lens onto two surfaces without affecting the image?
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36 views

How are optical lattices created, and how big can they be?

I am asking about the basic concept and the schematics of the laser configuration. How are atoms forced to stay in optical lattices? What lasers (power, wavelength, etc.) are used, and how are they ...
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0answers
49 views

Why does Light change color through Glass slab?

I shone a green laser light(~532 nm) through a glass slab and what I saw inside was that the light beam was now red. Imagine a regular refraction diagram but color the beam outside green and that on ...
3
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2answers
515 views

Finding the illuminance from a triangular light source

Since most light sources in games are point-like, it's pretty difficult to approximate area light sources with point sources. As triangles are a universal form to represent 3D models (thus area light ...
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1answer
225 views

Third-order susceptibilities of metals?

Can anyone point me to a source for measurements of the third-order nonlinear electric susceptibilities $\chi^{(3)}$ of various metals? Specifically in relation to the AC Kerr effect, so measurements ...
0
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0answers
16 views

What does “Polarization Gradient Cooling” mean?

I'm well versed with what "Polarization Gradient Cooling" refers to, as in how the process works and what the term refers to, but the term itself baffles me. What is a "Polarization Gradient"? The ...
2
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1answer
70 views

What exactly happens when total internal reflection takes place at a quantum level?

What happens when light interacts with the boundary between 2 mediums at a quantum level? Why is it totally reflected back when it is travelling from an optically denser to a less dense medium? How ...
28
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6answers
7k views

Why did high quality mirrors use aluminum coatings instead of silver?

I have two questions on mirrors. I’ve read that in the past quality mirrors were coated with silver but that today vacuum evaporated coatings of aluminum are the accepted standard. When I look at ...
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1answer
34 views

Optics of stationary waves

could anybody tell me how it Works if it comes to stationary waves created on the surface of water jet and optics? there are some crests and troughs which work like lenses, but if you have water jet, ...
3
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2answers
308 views

Fiber optics with broadband, incoherent light

I wonder if someone could help clarify waveguiding with broadband, incoherent light please. If we take a telecomms fiber, which is single-moded above ~1.4 μm and couple a laser beam in, we assume ...
0
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1answer
25 views

rare occurence of diffraction in light [closed]

My question is that how the diffraction is not a common phenomenon of light.Here the lunar eclispe also is on the same basis but the diffraction is only a feature of sound .how?
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0answers
16 views

Transmittance of yellow light through blue substance

I am performing an experiment in which I flash an LED-light through a substance with different opacities and do voltage measurements over a photoresistor on the other side. When I decrease the ...
0
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1answer
48 views

Point source behind a diffusing plate? [closed]

I am confused about the action of a diffusion plate in optics experiments (e.g. with the Michelson interferometer). Let us say we put a point source behind a diffusion plate, what will the set up ...
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2answers
773 views

Magnification in compound microscope

I was studying about compound microscope here I don't see why we multiply linear magnification of objective with angular magnification of eyepiece. Shouldn't it be both angular or both linear? Can ...
2
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1answer
514 views

Is there an equation to calculate efficiency of an optical fiber to transmit sunlight for length of 4 m

I want to transmit sunlight over a distance of approx 4 m via optical fiber. Ideally I want to light up the whole house with sunlight. I was reading that the largest diameter for an optical fiber may ...
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2answers
80 views

view angle independant focal point

Is there any way to design a lens or system of lenses where I see the same part of the image below the lens, irrespective of direction from where I am viewing. In the image uploaded, there is a black ...
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5answers
723 views

Why can a solution show optical rotation?

Why can a solution show optical rotation? A solution, as a liquid, is rotationally isotropic, right? So, even if the molecules are chiral, because of the random orientation of the molecules, shouldn't ...
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3answers
2k views

Do infrared lamps provide more heat than incandescent lamps?

Infrared lamps seem to be used in situations where you want to produce heat without producing (as much) light. But incandescent bulbs also produce heat. Why not just use incandescent bulbs? My ...
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2answers
172 views

Is this wave spatially coherent?

Is the following wave (the solid lines representing the intensity maxima) spatially coherent? I've been seeing different, seemingly contradictory definitions of spatial coherence. Some places ...
7
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1answer
337 views

What was Newton's own explanation of Newton's rings?

What was Newton's own explanation of Newton's rings? Newton advocated a corpuscular theory of light, but his rings would most conveniently be explained by a wave theory. How did he explain his own ...
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0answers
17 views

determine axial resolution in microscopy

I want to determine the axial resolution of a fluorescence microscope. As I understand, this is commonly done employing a thin fluorescent specimen and performing an axial scan. The axial resolution ...
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1answer
266 views

Why is an exciton only observed when we excite to the conduction band and not to other electronic level inside the bandgap?

Excitons can be observed when we excite electrons to the conduction band. I don't know about excitons being observed when we excite the electrons to an electronic level that would eventually be in ...
2
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1answer
735 views

Usefulness of half-shade in Laurent half-shade polarimeter

In the Laurent half-shade polarimeter, if the half-shade weren't there, what difference would it make? The light after being polarized by the Nicol polarizer,could have entered the tube containing the ...
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1answer
29 views

Fresnel equations for perpendicular angle of entry [closed]

In many text books one finds for the fresnel coefficients for light perpendicular to the surface: $$r = \dfrac{n_1 - n_2}{n_1 + n_2}\quad\text{and} \quad t = \dfrac{2n_1}{n_1 + n_2}.$$ When I try to ...
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1answer
38 views

Could you use polarization filters to make a privacy screen?

I remember seeing that brusspup video where the polarization filter on the monitor was removed and put it in his glasses, causing only the wearer to see the screen. (, and) I was thinking, would ...
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0answers
38 views

Can a naked eye see a single atom when it is resonantly driven by some laser beam? [duplicate]

Presumably, when the laser is strong enough, the fluorescence will be very strong too. So, is it possible to see a single atom with a naked eye?
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0answers
17 views

Analytical derivation of photonic bandstructure in photonic crystal

It seems the usual way to find the photonic bands of a photonic crystal is to setup the "master equation" $$\nabla\times\left(\frac{1}{\epsilon(\mathbf{r})}\nabla\times\mathbf{H}(\mathbf{r}) ...
3
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1answer
144 views

How to deal with coma and oblique spherical aberration in a Czerny Turner configuration?

I am modelling my own spectrometer using Zemax when all of a sudden I've been told that: even if you manage to optimize the angles or positions of the grating and the mirrors, you won't get ...
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2answers
52 views

Convex lens with object at the focus

When the object is at the focus, the image will be formed at infinity. What exactly does this mean? What will it look like if you hold the entire apparatus at arms length? Will it be extremely ...
2
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3answers
166 views

Single slit diffraction - choosing a wavelength?

For the classic experiment of determining the slit width of a single slit. If we assume the rough order of magnitude of the width is known. What factors determine the choice of wavelength? (Clearly ...
2
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0answers
39 views

Multi-directional ether

In the Michelson-Morley experiment,the two beams of light should be directed at right angles in order to test the existence of ether, but that postulate is based on the prediction that ether has only ...
2
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1answer
50 views

Why is intensity related to number of photons?

I have been reading up on Doppler broadening and have found a number of sources (for example here and here) which seem to be taking the number of photons in the range $[\nu,\nu+d\nu]$ to be the same ...
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0answers
21 views

On which factors does reflectance depend?

For my college physics project I'm planning to measure the change in reflectance of an object with respect to a factor (temperature, current going through, etc., not angle of incident, wavelength, ...
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1answer
54 views

How does one calculate how big something has to be, to be seen at a given distance? [closed]

Ignoring curvature of the Earth. How do I calculate the size an object would need to be in order to appear to be approx 1cm tall at a given distance?
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0answers
26 views

Superluminescent LED [closed]

How do Superluminescent LED generate amplified spontaneous emission? Moreover," a superluminescent LED combines the spatial coherence of a laser diode and the temporal incoherence of an LED. " Please ...
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0answers
40 views

Question related to optics [closed]

My teacher asked me a question, the question is this "Sunlight enters into a room thorugh a triangular aperture, when i place a screen nearer to the aperture it casts a triangular image, but when the ...
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6answers
27k views

Free Optics Simulation Programs

I'm having an extremely difficult time finding an optics program that is easy to use and offers accurate physics simulations. I'm not asking for much, I just want to be able to simulate a laser going ...
6
votes
4answers
5k views

Lasing in a 2-Level system?

What exactly is the difference between 2-Level, 3-Level and 4-Level systems? Why can we not achieve stimulated emission in a two-level system using optical pumping?
0
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1answer
238 views

Fringe Width and Spacing and Number of Slits in Diffraction Experiments

In a single slit experiment, the fringes are not equally spaced and aren’t of equal widths—the central maximum is the widest, the secondary maxima grow narrower and narrower outward, and the minima ...
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1answer
31 views

combination of lenses for undefined focal length

Good morning! I am not an optics specialist, but I need to know if it's possible to do what I tried to visualise in my picture. Basicly I want to merge two beams into one. I am thinking of using a ...