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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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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0answers
29 views

Chromatic aberration in human eye [duplicate]

A lens focuses the different colours of white light at different points. Since our eye has a convex lens there should also be such an aberration but we see objects clearly with normal eye. I want to ...
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4answers
26k views

What makes some laser beams visible and other laser beams invisible?

What makes the beam of some lasers: 1-visible? such as the ones used in clubs or such as the laser pointers sold at amazon which if pointed to the sky look like a solid visible beam of light ...
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3answers
7k views

How does a photon travel through glass?

This was discussed in an answer to a related question but I think that it deserves a separate and, hopefully, more clear answer. Consider a single photon ($\lambda$=532 nm) traveling through a plate ...
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1answer
20 views

difference between plasmonic wave plates and usual wave plates

plasmonic waveplates are constructed using the generation of surface plasmons. Is there any difference between these plasmonic wave plates and the usual wave plates used in optics, besides the ...
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0answers
30 views

Focusing light from a laser shot into one point [migrated]

Im planning to build a laser shooting target. Something like this: In the long term I want to build something advanced like a professional grade target, in which the able is able to tell exactly ...
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1answer
57 views

Combination of two concave lenses

When we have two convex lenses in contact we have the combination behaving as a converging lens. Can someone please give an analytical description for the combination of two concave lenses in contact ...
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0answers
16 views

Derive phase shift equation for two diffirent optical paths differences

If we have two optical paths differences, call them $\phi_1, \phi_2$, and $\phi_1 > \phi_2$ then phase shift with respect to optical path difference $\phi_2$ is $PhSh = \frac{2\pi}{\lambda}(\phi_1 ...
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2answers
55 views

What polarizes a rainbow?

What polarizes the light from a rainbow. I already did some search and couldn't get a clear answer. All I could find was the light is polarized on the direction light is entering. What happens to the ...
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2answers
214 views

Why the light bent towards the normal when they pass from rarer medium to denser medium?

Whenever the light rays are entering the rarer to denser medium they bend toward the normal. Then why the rays choose the path toward the normal? Why it cannot choose the path away form the normal?
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0answers
29 views

Limits on the information obtained through optical measurements

Consider a Gedankenexperiment shown in the figure below. There are two lasers $S1$ and $S2$ with exactly the same specifications on paper. In practice, they are of course somewhat different but ...
2
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0answers
19 views

statistical property of light reflected from a coarse mirror

This is a problem comes up in my study in correlation reflectometry. I'm wondering if there is a straight-forward way to interpret the phase and amplitude of the reflected light from a perturbed ...
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0answers
24 views

Magnification: Microscopes Telescopes

What is the difference between the way a microscope magnifies say a star and a telescope say a cell? Why is it, that the eyepiece of a telescope magnifies stronger when it is smaller and with a ...
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1answer
43 views

Reflectivity of Metals - real and imaginary part of k-vector and complex dielectric function

De electric field component of an electromagnetic wave that is traveling in the $x$-direction is given as $$E(x,t) = E_0 e^{i(kx - \omega t)} $$ with $E_0$ the amplitude and $k$ the wave vector. From ...
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1answer
2k views

What causes refraction of visible light? [duplicate]

Refraction is the bending of a wave when it enters a medium where its speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray toward the ...
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0answers
17 views

images formed by refraction

While deriving the formula for image formation by spherical refractive surface we assumed that object is placed at the principal axis and is like a point object. What if the object is not placed at ...
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0answers
17 views

image motion for projectile motion of object

a ball is projected from top of the table with initial speed u at an angle of inclination 'a' to the table. describe motion of image with respect to the ball on a screen located next to the table My ...
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1answer
165 views

Confocal Microscopy

In the context of Confocal Microscopy literature state, "spatial rejection of out of phase light".Is that mean only light which is pass through the pinhole is used and the rest is blocked ?
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2answers
234 views

Microscopy types and techniques? [closed]

I didn't get the basic difference in between the different types of microscopy. for example there are several different microscopy techniques are available such as Bright field, Dark field, Confocal, ...
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0answers
28 views

Plane wave conditions

Which conditions have to be fulfilled in order to approximate a light beam by a plane wave (i.e. $\phi(x)\approx \phi(0)e^{ikx}$)? I am looking for both mathematical and experimental conditions. At ...
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4answers
11k views

Difference Between Fraunhofer and Fresnel Diffraction

What is the difference between Fraunhofer diffraction and Fresnel diffraction? I mean diffraction is just bending of light waves or waves in general around a point. So how can there be two types of ...
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1answer
31 views

Optical path difference

Hello, i have question about calculating optical path difference. $\Delta L = (BC+CD)*n2 - BF*n1$ - why calculating path difference here we are substracting $BF$ segment?
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3answers
535 views

Why do rainbows have distinct colors?

When I searched on the Internet for the reason of formation of rainbows, I got many explanations like this one & this. All the explanations consider only one spherical water droplet (like this ...
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1answer
43 views

Oberving a photon through double slits

If we send a particle with mass through the double slits we observe a interference pattern. That is of course if we don't observe which slit the particle goes through. If we do then we get two peaks ...
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3answers
103 views

Violation of conservation of energy?

Imagine a perfectly spherical mirror with 100% reflection. Imagine a point source of light in the center. The point source keeps radiating light. Will the light undergo destructive interference ...
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8answers
2k views

Is it possible to blur an image in such way that a person with sight problems could see it sharp?

If someone has short or long sight, is it possible to tune image on a computer monitor in such way, that a person could see it sharp as if they were wearing glasses? If not, will 3d monitor make it ...
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1answer
35 views

Can someone give an intuitive understanding of Fano Resonance?

I'm reading about Fano Resonance. The line that almost every source I can find gives is something like (from the wiki): The Fano resonance line-shape is due to interference between two ...
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3answers
948 views

reflection at intersection of two mirrors

Consider 2 mirrors which intersect at an angle. If we draw a light ray intersecting the mirrors at their point of intersection, how will it reflect? What will be the normal at that point?
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19 views

Any good reference on crystal optics?

I am primarily interested in the birefringence phenomenon. Any good reference? I want something above the general physics level.
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6answers
10k views

Why are most metals gray/silver?

Why do most metals (iron, tin, aluminum, lead, zinc, tungsten, nickel, etc.) appear silver or gray in color? (What atomic characteristics determine the color?) What makes copper and gold have ...
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0answers
8 views

How does voltage sensitive dyes actually determine neural network in foetus?

In research topics of neurophotonics, the best way of determination of neural network in foetus is by using voltage-sensitive dyes instead of placing diodes. But how does it actually work? Sorry if ...
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2answers
38 views

Measuring image distance of a virtual image

How to a measure image distance of a virtual image without calculation? It is impossible? To measure it, we must have a real image to measure the image distance with a screen and a ruler. I saw it ...
10
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2answers
441 views

Why does sunset over a body of water cause a path of light stretching towards the horizon?

Have you ever notice the sunset's image in the sea? It's like long light path to the end of the horizon! I've attached a sample of this: How can we explain this? I know that it can happen even in ...
3
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2answers
58 views

Decoherence of a Coherent Beam

If retarding films (i.e. wave plates) can retard the electric components of light (based on the films thickness) without affecting it's direction, couldn't I use a retarding film of randomly varying ...
5
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1answer
60 views

Long, blurry reflections in wet road [duplicate]

When driving on a wet highway at night, any surface emitting or reflecting light will have a reflection right under it that is blurry and seems to stretch to infinity. This is not exactly what I am ...
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0answers
39 views

Can anybody explain about phase shift and phase spectrum terms in case of multidimensional signal?

I know about phase of a 1D signal, but when I move into higher dimensions like 2D or 3D etc, it becomes headache to grasp the concept. What do the terms "phase shift" and "phase spectrum" mean in ...
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0answers
58 views

Is it possible for someone traveling at the speed of light to see at all? [closed]

I know that the speed of light is the same for all observers regardless of your speed, But this question is really worth thinking about. If someone let's say managed to reach the speed of light, ...
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1answer
30 views

Polarization and Reflection [duplicate]

The polarization is a property of waves that can oscillate with more than one orientation. Given this, when the light is reflected from a surface, does the reflection change the property/orientation ...
5
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1answer
87 views

Does ordinary refraction exert a couple on the refracting medium?

Refraction gives rise to a momentum change orthogonal to the propagation direction. This must result in an equal and opposite change to the medium at the boundary. Entry and exit cancel, and the ...
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1answer
42 views

Why Image is not enlarged if we keep convex lens first and concave lens at last?

Well After successfully getting some concave and convex lens I started observing. At first I saw that if we keep concave lens near to your eye and just after x distance away if we keep convex lens we ...
10
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2answers
184 views

How do a microscope's optics expose defects in the user's vision?

I've got cataracts in both eyes. My vision is correctable to 20/30, so the cataracts are essentially a non-issue in daily living. But when I use a microscope, which I do daily, (binocular, zoom ...
2
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1answer
36 views

How much UV is reflected by glass?

On a sunny day, how much of the Sun's UV is reflected by windows? I suppose this boils down to what are the refractive indices of common window glasses, so that one might solve the Fresnel equations. ...
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2answers
40 views

Is the photon truly not absorbed in Raman scattering?

In reading about Raman Scattering, I was thinking while reading it "okay, incident photo absorbed by molecule, molecule goes to higher energy vibrational state, molecule re-emits photon with either ...
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0answers
28 views

Magneto Optical Kerr Effects

I have a few questions on MOKE setup. Firstly, why is calibration of the coils necessary? Is it to get a relationship between the voltage and the Magnetic field? Secondly, why do we have to normalise ...
0
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0answers
18 views

Is polarization a meaningful notion for an EM mode in a close cavity?

For a generic close cavity, I suspect that all the modes are non-degenerate? Therefore, in each mode, at each point, the E field has a definite direction, and consequently, it is meaningless to say a ...
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1answer
32 views

Plane Mirror as the Screen in Young's experient

If I place a plane mirror instead of the screen in the Young's double slit experiment, what will I see? Will the bands appear on the mirror face?
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1answer
72 views

Propagating higher order Hermite Gaussian modes. What are complex amplitude coefficients?

I've been tasked with writing a code (in MatLab, but I'm currently using Mathematica because I don't know MatLab %\ ...) to simulate the propagation of a Gaussian beam. I don't really know anything ...
3
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0answers
44 views

3D movie optics mathematics

I get the idea that we use two polarized light sources and a parallax rendered film such that the objects seem to resemble true parallax in our eyes once it passes through the polarized glasses, but ...
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6answers
4k views

Is it possible to witness a circular rainbow?

What conditions would make it possible to see a naturally occurring fully 360° circular rainbow? Would it even be possible?
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3answers
178 views

What really makes a rainbow happen?

Yes, a rainbow is formed when a raindrop refracts light, but why then does the whole sky not become a huge rainbow when it rains? Would the light not be dispersed into ordinary 'white' light? What ...