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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Diver view of refraction

I'm studying the refraction in optics. If a red light monocromatic beam of red light (700 nm) passes from air to water it becomes with a wavelenght of aprox 526 nm. So, my question is: How is going ...
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1answer
22 views

optics biconvex and plano convex

What is the resultant focal length If a biconvex lens is cut into half and then the resulting 2 plano-convex lens arranged in such a way that the plane surface of one faces the curved surface of the ...
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2answers
45 views

Correlation between color of light visible to us and the intensity of transmitted light by the material

I wanted to know if there is any relation between the color of light observed by the eye and the intensity of light transmitted by a material. Let us assume that I have a table of intensities of light ...
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0answers
35 views

Beamsplitter and Dielectric Mirror

Among two optical components. One is a Nd:YAG Laser 50/50 Beamsplitter and the second one is a Dielectric Mirror see pictures. Both of them almost looks like the same. If the specification is not ...
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2answers
69 views

Spatial and Temporal Coherence

How is it possible to achieve waves which are spatially, but not temporally, coherent? Can this be done with a bandpass filter? Conversely, how is it possible to achieve waves which are temporally, ...
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2answers
59 views

Fate of light ray

This question has been on my mind since I first learned optics. Where will the light ray go? First, I thought of it taking a U turn. But, I don't think that will happen. Now I have studied a bit ...
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2answers
78 views

How am I able to tell whether it is dark or not while eyes closed? [closed]

How am I able to tell whether there is a light on in front of me even with my eyes closed? The usual darkness whilst eyes closed transforms into a not so bright glow when my closed eyes are in front ...
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2answers
57 views

Plano-convex lenses

When the spherical side of a planoconvex lens is towards the source we will see reduced aberrations normally we use it for the beam collimation. When we use two planoconvex lenses configuration why we ...
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2answers
71 views

Layer thickness measurement

I am interested to measure the thickness of the coating on a mirror (e.g. in the picture below). What are the available and best way of measuring it? What will be the solution in case of multiple ...
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47 views

What is $\epsilon_\infty$ in this equation and why can it be neglected in the IR?

I'm reading this paper (warning, PDF) and they mention that the complex permittivity $\epsilon$ and complex conductivity $\sigma$ are related through the equation $$\epsilon - \epsilon_\infty = (4\pi ...
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1answer
29 views

Does bragg diffraction affect intensity of transmitted light?

Is it possible to measure the plane spacing in a crystal by measuring the angle at which transmitted light intensity dips?
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3answers
519 views

Why use lasers for intense, localized heat instead of some other light source?

Lasers are used in various industrial processes that need intense, localised, heat (3d printers and laser cutters come to mind). My question is: why use lasers? There are many other (cheaper, ...
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2answers
122 views

Passing Polarized light through multiple polarizers in series

This is a question that has been troubling me from many days: Suppose we pass a linearly polarized light through a system of 3 successive polarizers. The 1st polarizer is offset 30$^{\circ}$ from the ...
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1answer
66 views

simple question about collimating lens

Let me preface this by saying that I have a very limited knowledge of optics -- basically, I know enough to be dangerous. So I have a square Fresnel lens that measures about 10.5 inches on a side. The ...
2
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1answer
35 views

How is “Band Intensity” related to absorption coefficient

I am interested in the linear absorption of 762nm light near a transition of molecular oxygen. I need to find some experimental numbers that will tell us how far the 762nm light will propagate before ...
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0answers
52 views

What is clock or phase adjustment in projectors? Why its proper setting eliminates strange behaviour of 1px lines/ [closed]

I'm doing experiments that require using a big, thin, contrast grid, for example 1 black pixel and then 1 white pixel alternately. I've met with a few DLP projectors and in each of them I had to ...
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0answers
31 views

How do RGB colors work? [duplicate]

They say that all colors can be formed by mixing Red, Green, and Blue appropriately. Is it true? Isn't the Fourier basis infinite dimensional? Or does it turn out to be the case that only three ...
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1answer
80 views

Fraunhofer Diffraction using lenses [duplicate]

I've come across a question that I don't know how to tackle: An alternative way of observing Fraunhofer diffraction uses lenses to provide appropriate conditions. Sketch an optical configuration ...
2
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1answer
90 views

Why exactly are images formed by lenses/mirrors?

I just don't get the concept behind why a lens or a mirror forms a reproduction of the object at present. Is it to do with the object blocking parts of the light source? I just don't understand why an ...
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1answer
127 views

Reconciling total internal reflection and the evanescent Wave

I understand that light is guided in a dielectric waveguide via total internal reflection. My question is regarding the origin of power contained in the evanescent field traveling along the direction ...
2
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3answers
94 views

Why can colors be mixed? [duplicate]

We can combine colored light, creating other colors, at least in terms of visual perception. But how it the result physically "a different color" - if it is at all? Or is all this not a physical ...
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0answers
10 views

Can a $TEM_{00}$ beam incident on a confocal cavity along its optical axis excite modes other than $TEM_{00}$ in the cavity?

Can a $TEM_{00}$ beam incident on a confocal cavity along its optical axis excite modes other than $TEM_{00}$ in the cavity? If not, is the FSR of the confocal cavity $\frac{c}{2L}$ in this case, ...
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0answers
82 views

What is the effect of total internal reflection on polarized light [closed]

Total Internal Reflection causes phase change of a light beam. I searched for effect on a polarized light beam by Total Internal Reflection but could not find much. I am assuming polarization does not ...
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1answer
105 views

How car headlight works?

There are two headlight of car. One having a light bulb between two concave mirrors (one mirror behind and other infront of bulb), and the other type of light only have one concave mirror behind the ...
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1answer
1k views

Why do we see laser beams?

A laser produces a coherent beam of photons with particular $\mathbf{k}$ and $\mathbf{\omega}$. So, if there is no particular $\mathbf{k}_0$ directed toward our eyes, why do we see laser beams? I ...
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1answer
65 views

Imaginary number for extinction coefficient in complex refractive index

In complex refractive index on a material, $n=n'+ ik$, the imaginary part $k$ is physical meaning, as it shows absorption in the material but it is an imaginary. How we measure an imaginary values in ...
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36 views

Resonance condition in confocal cavity

In a confocal cavity, a beam traverses the length of the resonator 4 times between two transmissions along the same ray. . For example, in the above figure, path difference between two beams that ...
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1answer
67 views

Are Verdet Constants Temperature Dependent?

The Verdet constant of a magneto-optical material shows up in the calculation of the rotation of polarized light in a medium submerged in a magnetic field. The amount of rotation is given by $$ ...
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1answer
40 views

Why do the RGB gamut vertexes not intersect the edges of human vision on the CIExy plot?

As I understand, the CIExy graphic maps "greenness", or rather middle-wavelengthness, to the Y axis and "redness", or rather long-wavelengtsness, to the X axis. The trapping used to reduce the 3d ...
3
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1answer
48 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 ...
6
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1answer
79 views

Negative radiation pressure from negative refractive index?

I see this claim being originally made by Vesselago (the discoverer of the principles of metamaterials) and indeed in contemporary papers. It means that such a metamaterial would be pulled towards its ...
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0answers
45 views

Fraunhofer Diffraction [closed]

A 1-dimensional aperture is illuminated by a parallel beam of light of wavelength $\lambda$ and the diffraction pattern is viewed on a distance screen. Show that the amplitude of the diffraction ...
3
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4answers
101 views

What's the difference between Raman scattering and second harmonic generation in crystal?

As far as I know, the Raman scattering is from the stokes and anti-stokes scattering that the laser light interact with molecular vibrations. So we know that ""laser light interact with molecular ...
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73 views

Difference between the increase in optical path due to refraction and that due to reflection

If we place two glass plates of refractive index n and each having thickness t,on the way of a light ray the increase in optical path becomes (S2P-S1P)=2(n-1)t due to refraction through them,and the ...
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33 views

Optical brightener in plastics? [closed]

Is there any way to add some type of 'optical brightener' to a PC+ABS molded part? I'm looking for something that will not affect the color / gloss. Ideally it will be a material that can be added ...
5
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1answer
84 views

What is fidelity in experimental QM?

I often comer across the term high fidelity in QM papers. Does fidelity imply ratio of entangled photons / total photons? Is there some other metric to measure how good the source is?
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1answer
200 views

The skin effect and the reflectivity of gold

I am simulating a waveguide in COMSOL, a FEM solver. My model looks like this (it is similar to a standard Quantum Cascade Laser geometry): Therefore there is a very thin (30nm) layer of gold ...
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1answer
84 views

Alternate young double slit experiment

What will happen in young's double slit experiment, when instead of screen I put a black screen with a hole and a second screen behind the black one. Will it still form interference pattern albeit a ...
5
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2answers
219 views

Why must an integrating sphere be a sphere?

Why must an integrating sphere be a sphere? Why can't it be an integrating cube? What is the difference? Could I use a cube to measure total illuminance like an integrating sphere does?
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2answers
57 views

Mean free path of a photon in a fiber

Is there a way to calculate, or a reference table I can to look up which provides the average distance a photon travels before it encounters an electron and is absorbed or re-emitted in a fiber optics ...
5
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3answers
104 views

Wave or particle in the end

In Young's double slit experiment I put a convex lens after double slit and direct interference pattern on to a fibre. Then I expose the other end of fibre to a screen. What will I observe - the ...
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4answers
166 views

Question about the wave nature of light

I quote from my textbook, " Consider two vertical slits S1 and S2 placed parallel to each other, and a string is passed through them. The end B is fixed and A is given jerks perpendicular to its ...
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2answers
40 views

Why a minus in the equation of a paraxial plane wave?

paraxial plane wave = $\exp{(-jkz)}$ for waves propagating to the right I can't figure out why it's not $\exp{(+jkz)}$. Any help would be greatly appreciated, thank you.
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2answers
70 views

How fast is wave propagation in interference?

When someone performs Young's Double Slit experiment, the person sees an interference pattern on the screen. What is the time taken to for the pattern to appear on the screen? Is it distance between ...
4
votes
1answer
135 views

Will overlapping two different beams of coherent light cause interference?

I have two laser beams with same polarization running parallel to each other. Will they interfere? If yes, then what are the conditions (perpendicular distance etc) and how can I observe the ...
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1answer
288 views

What is the near point for the eye

So I am a teaching assistant for an introductory physics class. One of the problems on this weeks workshops is: Where is the near point (far point) of an eye for which a contact lens with power of ...
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2answers
84 views

Locations of destructive interference for two spherical waves

I have looked at this, but it did not help with locations. Really this just comes down to mathematical manipulation, which for some reason I fail to see. Here is my paraphrased setup: Consider two ...
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1answer
58 views

Graded Index fiber

In the following picture of a graded index fiber two different modes are depicted. One is a higher mode which is propagating towards the core-cladding interface and one is through the higher ...
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3answers
86 views

When polarized light hits a polarizer, what happens to the polarization which is not transmitted?

It is typically said that in polarization of light only those waves can pass through a polaroid which has a plane of vibration parallel to the axis of polaroid. My question is: what happens to the ...
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What is the difference between dispersion and differential mode group delay?

I want to know what exactly is the differential mode group delay in optical fibers, is it the same thing as dispersion?