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Constructing a chriped dielectric mirror for negative dispersion for ultrashort laser pulses resulting in group velocity delays

I'm currently looking at designing a chirped mirror for a project but I am confused over several aspects. I understand the principle of a chirped mirror in terms of how a laser pulse has a broad set ...
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2answers
30 views

How does change in medium affect object distance/image distance?

Say,we have a container filled with a liquid of refractive index $7/5$ upto a height up $H$. There exists a plane glass mirror at the bottom of the container. Now if a fish were placed at a height of ...
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0answers
11 views

When light reflects from a medium of lower index of reflection to a medium of higher index of refraction, why does the light undergo a phase shift? [duplicate]

I learned in my physics class that there is a phase shift when light reflects off a low $n$ from a higher $n$, but never got the explanation.
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3answers
70 views

Why don't E&M fields change orientation after hitting a surface?

In essentially every derivation of the Fresnel equations, the general problem of radiation hitting a surface at a certain angle is broken into two parts (out of which we hope the solution any general ...
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2answers
30 views

Will the thickness of a material affect the reflection properties

Does a thicker piece of material(lets say metal) reflect wifi signals the same as a thinner piece of material? I realise that thicker materials would block out more at the back, but my question is ...
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0answers
5 views

Height of a point in a plane given a measure of luminance

Context Assume a left-hand rule coordinate system and X points right, Y points up, Z points out. I have a camera facing perpendicular to the X-Z plane in the negative Y direction. I have 4 ...
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0answers
20 views

Mirror shake emulation for the light

Is there any way to simulate mirror shaking? Final goal is to make send light beam to the mirror and get reflected beam the same, as it happens if mirror is vibrating. Mechanical vibration is limited ...
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1answer
23 views

Frequency dependence of electromagnetic reflection

I was surprised to see that the Fresnel equations for reflection depends on refractive index and angle of incidence, but they do not depend on frequency. Why is this case? Are they restricted to ...
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1answer
20 views

Is perfectly diffuse reflection entropy maximizing?

Suppose that I shine light on a surface and none of it will be absorbed or transmitted, and the spectrum doesn't change (so that all that's left to determine is the power reflected from the surface as ...
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1answer
50 views

What is the difference between a white object and a mirror in terms of heat absorption?

Will a white object be cooler than a mirror when exposed to direct sunlight? Or will it be the other way around? If mirrors bounce all visible light and some of the other elements of electromagnetic ...
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1answer
22 views

Blue light is reflected, red is not. What happens to other visible/non-visible light?

The problem says: The certain film on the glass reflects blue light of wavelength 480nm, but does not reflect any red light of wavelength 640nm. 1) If we say that it reflects blue light but no red ...
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1answer
45 views

Why does phase of a wave change after reflecting from a denser medium?

Why does phase of a wave change when reflected from a denser medium, but no change takes place in phase during transmission?
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1answer
25 views

Reflection in Finite Square Wells

For a Finite Square Well where we have a wavefunction $\psi(x)$ which is an energy eigenfunction with eigenvalue $E = 2V_0$ in the following potential: $V(x) = \begin{array}{ll} 6V_0 ...
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1answer
78 views

How does QED explain reflection? [duplicate]

By reflection of photons from a mirror, the mirror must get an impulse of 2p=h/pi.l for every photon. This means that the mirror receives kinetic energy. But the photon has the energy it has before ...
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3answers
78 views

Why do shiny surfaces reflect more light than other surfaces?

I'm an A-level student and I love learning new things in physics. A new concept that I learnt says that the reflection is due to the scattering of light by electrons in the material. I've got my ...
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0answers
29 views

How can air pollution contribute towards light pollution?

I was just wondering if air pollutants such as soot, could reflect light into the night sky, and thus be a potential source of light pollution. If that's true, can you please suggest any other air ...
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11answers
13k views

Why don't we hear sound reflecting from buildings, mirrors, etcetera?

We can see buildings, doors, cars etc. as light falls on it gets reflected to us. but why doesn't the same thing happen with sound? I mean why don't we hear sound reflecting that much?
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0answers
62 views

What happens to Newton's Third Law during the reflection of a pulse from a free end?

Well, it is known that a pulse gets inverted when it gets reflected from a fixed support while the polarity of the pulse remains same when the incident pulse gets reflected from a free end. However, ...
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1answer
896 views

Why is everything not transparent? [duplicate]

There is a related question on this site here: Why glass is transparent? Which explains that glass is transparent because the atoms in glass have very large energy differences between energy levels ...
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0answers
37 views

Why do different color materal differ temperature in the same sunlight?

I have a blue, red, and green cup and put a thermometer in each. Of the 3 the blue cup had the coldest temperature inside, then green, then red. I understand there may be differences in 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
39 views

Number of photons through glass [closed]

I am getting mixed information on the total photon count involved with light transmission through glass. I'm not looking for percentages and I don't have equipment to count photons. For simplicity ...
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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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0answers
26 views

Standing Waves in a String of two Linear Densities

Given a string with sections of two linear densities like this: Does the point where the two linear densities meet have to be a node if a standing wave is produced? Are there alternatives? Could I ...
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0answers
23 views

How do Hertzian dipoles relate to reflection of EM waves?

We recently performed an experiment where the intensity of microwave radiation reflected off different materials was measured. A comment in the script noted that the mechanism by which reflection of ...
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0answers
65 views

Please explain this optical phenomenon, as seen from the top of the cup [closed]

So here is a cup, and i poured some water in it. The question is why do i see those multiple reflections? What causes these images?
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2answers
49 views

Can decoherence occur just by simple reflection?

I create an entangled photon pair. One photon is sent inside a resonant cavity which reflects the photon many number of times. Will there be decoherence between photon in the resonant cavity and its ...
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2answers
85 views

Why is this laser beam being scattered(and not)?

I was shining a laser beam through a liquid filled test tube(an ester particularly),and I found this phenomenon rather intriguing.Have a look. Now when I passed the laser straight through the ...
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2answers
202 views

How does light change directions? [duplicate]

To the best of my knowledge, light will always travel at the speed of light. How then does it get reflected and change directions? Wouldn't it have to decelerate, come to a stop, and then accelerate ...
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0answers
32 views

Why is the moon white? [duplicate]

Why is the Moon white? What is it's geological composition and how does that relate to it's apparent "color"?
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2answers
9k views

Why does a mirror split my laser beam?

Last night my daughter was asking why a mirror "always does that" (referring to reflecting a spot of light). To help her figure it out, I grabbed my green laser pointer so she could see the light ...
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0answers
32 views

How does the deflection of force on a tire work?

So, considering the example of a car that is turning, is all the force lost that's not along the axis of rotation of a tire, or is there some way to calculate how much of that force gets deflected ...
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1answer
37 views

Deep confusion with conventions and signs in geometric optics

This is an equation given in my book. The question is why have they used a negative sign on the LHS? Now, if you try to derive the mirror equation with simple geometry, you get 1/v +1/u =1/f . ...
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1answer
24 views

What happens to light when an optical cavity path length doubles instantaneously?

Let's say we have light contained in a cavity (of initial length $L$) and then instantaneously remove the second mirror, thus removing the barrier between the first and a third mirror which is some ...
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2answers
50 views

Is it possible to save the light?

I am just thinking why can't we save the light (not a bulb). Lights normally get reflect by mirror, when source is off reflection is gone or absorbed or discharged by other object in room. Can't we ...
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1answer
38 views

Blue hues in Aluminum mirror

[][] When depositing Aluminium sometimes I end up with a bluish hue to my film especially when changing angle of view. I use a very high rate of deposition and low temperature. What would cause this?
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1answer
49 views

Reflective angles from a CD [closed]

How do I estimate the diffraction angles of laser light which illuminates a CD? Does the storage capacity have an impact? Theories I have considered are: refraction diffraction $\sin(\theta)=\frac ...
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0answers
39 views

What happened to the perfect mirror?

Back in 1998 an article was published in Science by JPL's Jon Dowling claiming a method for making a perfect dielectric mirror: "Mirror on the Wall: You're Omnidirectional After All?" Jonathan P. ...
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2answers
46 views

Shape of a mirror that focuses non-parallel light

If I am not mistaken, a parabola is the shape that a mirror has to be to focus ideal, parallel light rays to a single point. Real light sources are usually not actually parallel though, but are more ...
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0answers
54 views

Light absorption, reflection and transmission [closed]

I was bothered by some explanations in the internet about light. Can someone correct me or answer my questions regarding on how electrons react when hit by a photon in different situations: ...
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1answer
55 views

Concentrating the Sun with mirrors facing each other

What will happen if the sun is concentrated by directing sunlight to mirrors that are facing each other? i know that mirrors absorb light and dont reflect 100% but will the efficiency increase due to ...
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3answers
104 views

Where do the energy and momentum come from when light is perfectly reflected on a surface?

If you send a light beam to a surface which reflects the light perfectly I would say that on the surface is put a force of the light so the surface moves backwards. But where does that energy comes ...
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3answers
2k views

Why is sound reflected and not transmitted through a wall?

We know that speed of sound is higher in a denser medium. So when a sound wave strikes a wall, why does it echo instead of passing through it with a speed faster than the speed of sound in air?
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1answer
29 views

Polka dot beamsplitter. Is it good for gaussian beams

I am doing pump probe and I am looking for beam-splitter which will not affect beam polarization too much, as I intend to measure polarization dependencies. I have heard of polka-dot beam-splitters ...
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1answer
53 views

Can electrons within a positive ion absorb and reflect light?

I understand that in a crystalline metallic structure, such as one making up a bar of gold, there are one, or more, valance electrons of each atom that have left their outer shell (became free ...
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0answers
43 views

How to solve this problem : A glass sphere of radius 1 m and refractive index 1.5 is silvered…? [closed]

Problem: A glass sphere of radius 1 m and refractive index 1.5 is silvered at its back. A point object is kept at a distance of 1 m from the front face, as shown in the figure. Find the position of ...
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2answers
88 views

Why is reflected light polarised?

Why is reflected light polarised? I have learnt about Brewster's angle, and how at a particular angle all light reflected is polarised, but do not understand why. Is this something that could be ...
2
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1answer
42 views

Sound insulation, absorption and diffusion. Can they be part of the same process? [closed]

I understand that insulation, absorption and diffusion in acoustics are different concepts. Notwithstanding, would it be correct to assume they may be part of the same process when all are used to ...
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0answers
35 views

Polarisation effect due to reflection [closed]

By Malus' law we know that when an unpolarised light falls on a thin glass sheet, the light that gets reflected is polarised light as only the s-component (only 15%) is present with very low intensity ...
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1answer
56 views

Will I see the light?

There is a perfectly smooth wall. We have a slit parallel to it. Through that a laser beam passes. As the slit is parallel to wall the laser beam will hit it normally. So now if I see obliquely I ...