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 eyepiece does not resolve image formed by objective lens further?

In my book it is written that "The angular resolution of the telescope is determined by the objective of the telescope. The stars which are not resolved in the image produced by the objective cannot ...
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64 views

DIY optical band pass filter or another alternative

I need to detect laser using a solar cell which would need me to either detect the laser wavelength or use pulse modulation and detect the frequency so I'm kinda here to ask if it's possible to simply ...
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53 views

Will smoke affect young's double slit experiment

If smoke is present in between the screen and slit in Young's double slit experiment using laser, will there be any change in the interference pattern? Will the fringes be obtained on the screen? ...
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1answer
41 views

Why rainbows form around flashes?

I read that to see a rainbow, your back must be towards the sun, and you have to look at roughly 42 Degrees from the imaginary line to spot the red band. But many times, me and many of my friends see ...
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2answers
95 views

Why do you need at least two rays to form an image?

Why isn't enough one light beam to form an image in your retina for example?
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32 views

Holography with object and reference waves with a slightly different wavelength

Recently I've been looking into holography, where one interferes the object wave with a reference wave and encodes their combined intensity on a transparency, so that if one then re illuminates the ...
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5answers
271 views

Blue light filtering

Prologue: my knowledge in these topics is fairly limited, so please feel free to point out the mistakes or the not-so-clear points, and bear with me for the oversimplicity of the language used. I was ...
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2answers
165 views

Why does a laser beam stay collimated?

I am looking for a simple way of explaining the collimation of a laser beam. The typical discussion of the two slit experiment of quantum theory relies heavily on the Huygens principle. Its ...
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1answer
58 views

Wave vector relation in nonlinear material

A light wave ($k_1,\omega_1$) travels in a medium of refractive index $n_1$ and then encounters a nonlinear medium ($n_2$) under the angle $\theta_1$. Snell's law tells us the wave's direction in the ...
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25 views

Temperature influence in Optical Quantum Computing

I've recently been looking into the (perhaps a bit outdated but still very interesting) field of linear optical quantum computing. Using photons as information carriers, and using objects like ...
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1answer
164 views

In Young's double slit experiment the fringes are non-localised. Why? [closed]

What is meaning of non localiesd fringe ?Why they are non localised ?
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53 views

What is the reason behind total internal reflection?

I know that when we increase i , r increases unevenly, i.e i increases a little but r increases with a greater amount. At some time, when i reaches the critical angle, r becomes 90 and if we further ...
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0answers
69 views

Why must this boundary condition be met? (Electromagnetic wave at interface between two mediums)

My textbook says that The laws of Electromagnetic Theory (Section 3.1) lead to certain requirements that must be met by the fields, and they are referred to as the boundary conditions. ...
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27 views

Phantom blue lights under white LED headlights?

Why do I see phantom blue lights just under (and a little to the left) of white LED headlights? They appear over where the fender is, so just a few inches below the actual lights. As the vehicle ...
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1answer
67 views

The many faces of electromagnetic waves

In my waves and optics class, we have learned several ways to treat electromagnetic waves: light rays (geometric optics), electromagnetic plane waves, spherical waves, cylindrical waves (2D). One ...
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2answers
69 views

Is Huygens's Wave Theory still correct?

We have to study on details about Huygens's Wave Theory though we have Electromagnetic theory, quantum theory today. Is it still correct or not?
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1answer
54 views

How we are able to see red and green colored objects simultaneously if combination of red and green produces yellow?

If red and green cones in our eyes are tiggered simultaneously then our brain makes us see yellow color. But if two objects which have red and green colors respectively are placed infront of us then ...
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1answer
31 views

Why does Diffracted Light cone diameter change in relation to angle of light beam?

I have a question about light diffraction. Take a look at these images of the Pantheon oculus. Now what I don't understand, in the first picture, the light is coming in from overhead and forms a ...
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2answers
103 views

Medium with refractive index less than unity?

What I really can't understand,What are the properties of a medium with refractive index less than unity?how does it effect light rays which fall on them?
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2answers
44 views

Total internal reflection in a simple pane of glass - why can we see through?

Consider looking through a glass window pane at high angles of incidence. At the front face of the pane, there is no total internal reflection since the light is traversing an air to glass interface. ...
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1answer
33 views

How do we call in English scientific terms the Fermat's principle about back and forth light traversal?

We know that the path followed by the light from point A to point B is independent of the direction of propagation of light. This is what is called in French "le principe de retour inverse de la ...
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183 views

Why should angle of incidence be equal to angle of emergence for minimum deviation in a triangular prism?

When I was solving questions on Ray optics I encountered a question wherein I had to prove that when a ray of light undergoes minimum deviation through a triangular prism then both the angles of ...
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1answer
64 views

When is a negative focal length used in optics?

I'm getting confused with conventions. I was wondering if this logic is correct: If an image appears on the same side of an object, then we use a negative focal length for determining information ...
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26 views

What are the figures of merit/ performance measurements I can use for deconvolution?

I'm currently performing deconvolution on a bunch of 2D slices of fluorescent beads using MATLAB. Now I want to measure the performance of different deconvolution methods on the filtering of the ...
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0answers
28 views

How to spread out a beam from a moving head [closed]

I have a couple of small moving heads available here I'm using them for the band to focus on particular musicians sometimes and I would like to be able to make the beam angle wider. Sometimes I have ...
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2answers
41 views

Why does resolution decrease due to out of focus blur?

Reading the Wikipedia article on Brightfield Microscopy and I notice the point: 'Low apparent optical resolution due to the blur of out of focus material.' in the Limitations section. I ...
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1answer
101 views

Total number of primary maxima in diffraction grating

I am trying to determine the total number of primary maxima that can be observed when light of wavelength 500 nm is incident normally on a diffraction grating, with the third-order maximum of the ...
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1answer
69 views

Why is there “ringing” at the violet end of a rainbow but not the red end?

I've recently noticed that if you look closely at the violet end of a rainbow, you can see a sort of "ringing" effect where there are alternating bands of color and lack of color. You can apparently ...
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10 views

Does the distance away from a plane mirror affect the Image seen by the eye? [duplicate]

Does the distance away from a plane mirror affect the Image seen by the eye? According to my textbook, it doesn't. However in real life, I see less of myself as I get closer to a mirror.
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7 views

Position in reciprocal lattice (for Triangular real lattice) to find photonic gapmap

To find Gap-Map, using FDTD, for square lattice of dielectric coulumns in air, I choose the 'X' position in reciprocal lattice, while varying the radius of the rods. The result is good. But while ...
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2answers
85 views

Can focused light be treated as a point source?

Imagine there is a uniform, collimated beam coming from a distant light source. This beam passes through a lens and is focused to a point at the focal length. Can this "point" be treated as a point ...
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2answers
411 views

Why is diamond transparent while graphite is not?

Diamond and graphite are both made of the same atom, carbon. Diamond has a tetrahedron structure while graphite has a flat hexagonal structure. Why is diamond transparent while graphite is not (at ...
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61 views

Derivation of the formula related to number of images?

I have read in my book that if two mirrors are inclined at an angle $\theta$, if 360/$\theta$ is even , the number of images is given by (360/$\theta$) -1 What is the derivation of this formula? I ...
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1answer
42 views

Why does the 4f lenses configuration decrease aberration? [closed]

In many publications/lectures it is said that the 4f lenses configuration is the preferred configuration for imaging. My question is why does this configuration in an imaging actually minimizes the ...
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2answers
70 views

Can light be rotated using lenses or prisms?

I was wondering if it was possible, by using only lenses, mirrors, or prisms, to rotate a ray of light coming from a certain direction. For example, if I have two lasers beams side by side, is it ...
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63 views

What happens to scattered light when intensity of light increases?

Does increasing the intensity of the incident light increase the proportion of the light that is scattered?
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51 views

Terminology - optical (visual) properties of a structure

I am trying to understand few terminological problems that I encounter. Without knowing keywords it is hard to perform search for literature or publications in the area. The area relates to the ...
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1answer
51 views

Why does this illumination pattern of an LED light going through a small pinhole not emulate the point spread function?

I have an optical setup where a component LED passes through a 50 um pinhole, and creates an illumination pattern on an image sensor approximately 5 cm away that looks like the following: Now, I'm ...
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1answer
47 views

Is it possible to get a lasing from every luminescent media?

Let's assume that there is a cavity with a couple of mirrors and gain media between which possesses luminescence under some external excitation/pumping. Let the absolute quantum yield of the gain ...
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1answer
79 views

What happens to photons, electrons, etc [duplicate]

What happens to photons when they hit our eye? where do they end up? if they generate heat, why our eye don't get overheated? Similarly what happens to electrons when the light hits certain metals, ...
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2answers
88 views

Is Huygens-Fresnel principle applicable for waves other than light?

In Wikipedia it was mentioned Luminous disturbance so I Did get confused that this principle only works for light waves and not for all of the Waves. Like some mechanical waves example wave on string. ...
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2answers
67 views

reflection of light on surface of solid

In a Scientific American article from 1968 in which he explains classically how light interacts with matter, Victor Weisskopf states that "the reflection of light on the surface of a solid or liquid ...
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0answers
50 views

Pair of Mirrors Facing Each Other [duplicate]

If you have two mirrors facing each other and you introduce a light source into the reflections and you take the light source away, would it immediately go away for all reflections in the "tunnel" of ...
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1answer
47 views

Reflection of light on semi-infinite solid

The following statement is often made concerning reflection on glass: "When light is normally incident on a glass surface, about 4% gets reflected and the rest is transmitted. The reflected wave is ...
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4answers
120 views

Is the Air Blue? [duplicate]

Randall Monroe, a credible source in my opinion, says that the sky is blue because the air is: Normal light interacts with the atmosphere through Rayleigh scattering. You may have heard of ...
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1answer
58 views

How to perform a rotation of field of view using only mirrors/lenses?

How does one rotate a "microscope" fluorescence image on the detector using only lenses and mirrors in the set-up shown above? I am trying to do ray tracing to understand how to do this, but lenses ...
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1answer
32 views

Given a light diffracting through an aperture of radius r, how would we find the radius of the beam at a position x meters away?

If we have a light source, say a laser or LED, diffracting through a circular aperture of radius $r$, how would we find the radius of the beam at a position $x$ meters from the optical axis? I ...
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1answer
92 views

Why do we see just one octave of light? [closed]

When one takes a look at the usual chart of EM spectrum one cannot help but notice that visible spectrum is slightly below one octave of frequencies; that is, the ratio between the highest and least ...
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0answers
26 views

Special case of mirror formula [closed]

Can anyone show me how to prove the mirror formula when the object is between focus and pole in a concave mirror
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32 views

3D glasses: how do we tell whether a doubly-rendered image is closer or farther than the screen?

This is a followup to this question: 3D glasses giving the opposite effect to that expected The current top answer explains that objects perceived as beyond the plane of the screen, as well as object ...