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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Fringe Localisation

How am I to understand where the fringes of a given setup are localised? For example, Young's double slits have non-localised fringes, that is the fringes are localised (and so are well formed) at ...
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Absortion of light by a plasma

Considering a plasma generated in a fixed volume by increasing the temperature of Helium gas from the environment temperature (this temperature is not stated) and an initial presure of 0.001 Torr, to ...
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Making a bright beam of artificial white light

For educational purposes, is there a way to make a narrow bright beam of white light without much equipment and without using the sun as the source? The collimated beam should be about 2 mm wide for ...
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Would an inverted design of a laser phosphor display (LPD) work?

Background info... It is my understanding that a laser phosphor display works by emitting RGB laser beams through a mechanism that cycles them in a pattern similar to a cathode ray tube. When I read ...
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Criterion for resolvability and spot size for optical systems

Look at the following table: By spot size I mean if we have a point source for the object, the angular radius of the spot created by the source as viewed in the image plane. My question is is all ...
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28 views

Determining the focal length of a gradient index lens

There are three subquestions in this question, all marked bold. Let's consider a planoconvex gradient index lens of thickness $d$, radius $R$ whose refractive index changes with the distance from ...
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Calculating the beating length of the directional coupler

I want to determine the coupling length needed to achieve a certain power coupling coefficient of a directional coupler. Recently, I read a paper titled "Ultra-compact high order ring resonator ...
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What's the difference between on-axis and peak intensity for a Gaussian beam?

I am asked to find the ratio of the on axis intensity at z=zR (Rayleigh range) to the peak intensity, given that the Gaussian beam solution is: ε(ρ,z) = ε0 (ω0 / ω) exp(ikρ^2 / 2R) exp(-ρ^2 / ω^2) ...
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What criterion did Abbe use?

For a microscope (correct me if I am wrong) the Rayleigh Criterion gives us: $$ R=\frac{1.22 \lambda}{NA_{condenser}+NA_{objective}}$$ But with the Abbe diffraction limit: $$ ...
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Diffraction in Circle of light? [duplicate]

I'm working on a project that refers to optics. the question says when a laser beam is aimed to a wire ( perpendicular to the surface ), a circle of light then will be seen on a the surface. I somehow ...
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69 views

Image formed by Refracting light

A jellyfish is floating in a water-filled aquarium 1.33 m behind a flat pane of glass 4.30 cm thick and having an index of refraction of 1.5. (The index of refraction of water is 1.33.) Where is ...
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Why does light reflected on water tends to 'smear' in the vertical direction? [duplicate]

I have noticed that in city lights reflected on the water are very often smeared more in the vertical direction (relative to the reflecting plane I presume), than in the horizontal direction. See, for ...
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Understanding Braggs x-ray diffraction and why light is treated as a single “ray/line”

I'm not familiar with optics. So my knowledge of treating light as single lines is almost completely foreign to me. Although I do know something about EM waves and Maxwells equations, so you can ...
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44 views

Far-sightedness problem

Let's consider BOB and HENA have far-sightedness problems, and they uses lenses to correct their vision. Somehow, they exchange their glasses; how then can we determine the closest object distance ...
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Scattering of strong non-resonant light by cesium vapor

can anybody provide good references (research papers, books,,reviews, recent...) about a VERY strong NON-resonant light scattering from a cesium atomic cloud/vapor? (The light should be capable of ...
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42 views

Why can one see the outline of a white sheet of paper kept on another white sheet of paper?

Why can you see the outline of an object of a color that is in front of another object of the same color.
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59 views

Is near point defined for a myopic eye and far point defined for a hypermetropic eye?

I learnt about far Point of a myopic eye and near point of a hypermetropic eye. But I am confused about the above question. And if near point is defined for a myopic eye and far point defined for a ...
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18 views

What is the transfer function in fft beam propagation for unpolarized light?

What is the transfer function in fft beam propagation for unpolarized light ? How to construct the fft beam propagation ? This is for homework. For coherent light the beam propagation is E(x,z) ...
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Why are certain opaque objects so biased?

Why is it that most of the opaque objects only block em waves in the visible spectrum but fail to block waves with frequency higher and(or) lower than the visible spectrum?
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Optics Network NEED good Reference or TEXT

I am using Optical Networks: A Practical Perspective, 3rd Edition (Amazon link) as a reference for studying optics network. The main focus of the course is rather on the layer, data, and protocol side ...
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60 views

Reflection and refraction of light [duplicate]

When a light ray strikes an interface a part of it gets reflected, a part of it gets absorbed while another part gets refracted. Why does light reflect? Why does it refract?
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Intensity of waves in single-slit diffraction

So I am trying to determine the relation between intensities of waves in single slit diffraction. Since I am pretty new to this topic, I couldn't find a way how to calculate the ratio between the ...
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scintillation of U/HE cosmic rays in snowflakes

Suppose there is a U/HE, a snowflake, and a human observer. What range of energies would produce visible effects? What would the reaction cross section look like? I don't know enough about the ...
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How much cheaper and smaller on average is SiPM technology over conventional PMTs?

I've heard it said that some of the major advantages of silicon photomultipliers are its low cost and compactness when compared to widely used photomultiplier tubes, but haven't found much information ...
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27 views

Laser beam sensed by scattering

Can a laser beam, whether it is a IR laser or of the visible to human eye spectrum, be seen/sensed by an electronic eye like a photosensor/photodetector, not human eye, if the beam is just in air? For ...
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37 views

How far away are we from a UV LED operating at around 100nm?

So far, we are down to around 250nm for UV LEDs. If I could get one at around 100nm that would ionize air I would find it very useful. Any ideas on whether this wavelength is feasible for a LED?
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Implementation of Expectation Maximisation tomographic reconstruction

I'm trying to implement iterative expectation maximisation reconstruction for emission optical computed tomography, very similar to SPECT reconstruction. The algorithm given in the literature is ...
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In Young's double slit experiment how can we determine the shape of fringes formed?

Does the shape of fringe change if the type of source is changed (point source or extended source) or if the relative position of slits is changed (both lie on a line either horizontal or vertical to ...
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30 views

The first term of Stokes Vector of natural light is zero?

Consider the electric field of a beam of natural light: $$ E(r,t) = E_0 \cos(k·r+wt) $$ Since this beam of light is natural, the vector E has all the components possible that satisfies: ...
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49 views

With the new time cloak technology could it be possible to stop time for everything except one person

So I was just reading up on some new research on national geographic from the Cornell University scientists and it seems that they've managed to bend waves of light around something to hide it from ...
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49 views

What exactly is an image?

When we say several rays meet to form an image, what is that which is formed? Is it an arrangement of unknown entities? What exactly am I looking at when I see my image in a plane mirror?
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How does a, halftone screen work?

Forever I've seen explainations that say a halftone printing image is made by photographing through a screen. But I have yet to see explained how that does the trick. Apparently the screen is placed ...
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51 views

Is there a way to cancel lens effects?

If I had 2 identical lenses, and put the two facing each other in oposite directions, would their effects be cancelled? Is there a way it could be done, maybe with fresnel lenses, so that it would ...
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light is allowed to pass through transparent objects? [duplicate]

light passes through transparent objects like water and glass ,where in case of glass the molecules are more tightly packed or concentrated then to it allows light to pass, Why?(yet reflection occurs ...
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Electro-Optics, Where to Start Studying

I have an opportunity for pursuing my Doctoral studies in a Electro-Optics domain. I have been chosen because I fulfilled the other criteria to secure the opportunity. I still have quite a lot of time ...
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Why does Threshold current of laser increase with the increase in temperature?

Why does Threshold current of laser increase with the increase in temperature? I know that at the same current level, the power is higher at lower temperature but why?
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How do I derive Sommerfeld's solution of the case when the incident ray is aimed obliquely to the edge of the screen?

I already know that the Sommerfeld's solution to this problem is conical. But internet does not show me the simple of exact derivation of this solution. How do I solve this problem?
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43 views

faraday's rotation for revealing hidden text

I'm trying to come up with a twist on the known faraday's rotation experiment involving a laser projecting into a polarizer. the polarized light then passes in a selenoid containing a glass rod. the ...
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Images formed by concave mirror of objects placed between center and focus do not end up as expected

I am more involved with mechanics at this moment, but my sister in 7th grade pointed out that when objects placed in between center and focus of a concave mirror are 'too big' the simple two ray ...
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Length of Focal Spot Along the Optic Axis

I am currently attempting a physics question on optics. A Fresnel Zone Plate has overall radius a and contains N half-period zones. The odd-numbered zones are open but the even -numbered zones are ...
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Limitations of (non-lightfield) near-eye displays

The answer to Is it possible to blur an image in such way that a person with sight problems could see it sharp? suggest that you cannot present a "counter blurred" out-of-focus image such that it ...
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55 views

How does airborne laser system deflect the laser beam?

In the Airborne Laser system, the laser beam is directed from the nose of a Boeing airplane towards the target. In this system, the angle of laser beam with respect to airplane body can be changed at ...
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Solution of one dimensional wave equation by variable separation method

When solving the One dimensional wave equation by variable separable method, we equate left-hand side and right-hand side to a constant which is negative in nature. Why has the constant be only ...
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What curved, transparent media exists for full-motion holograms?

Looking to project light either on, or through, but not from, a transparent medium. So I'm thinking of half a hollow sphere with a surface thickness of 1/10th the radius of sphere. A clear curved ...
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Photonic slab: 1D or 2D guide?

I have read several books that start talking about photonics wires by describing the slab guide first. Obviously, this kind of structure is a simplification of a 2D waveguide. My question is related ...
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what factors cause the “energy gap” to change between different materials?

To my understanding, every electron wants to be "excited" its next energy level. Depending on the material, the electron will need a different amount of energy to reach the next energy level. This ...
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Jaynes-Cummings Model in Quantum Optics

Why doesn't JC model remain valid under the weak atom-field coupling?
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Optical density

My knowledge about optical density as a quantity is limited and I have several questions regarding it. I know that it is the optical density of a medium that determines the speed of light in a ...
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Transparent vs Insulator

Being transparent, can I say that glass is a better insulator than wood. (Reason: In GLASS visible light(lower energy)is not able to excite the electrons in it,so just pass away to other ...
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Merging shadows [duplicate]

It is a strange phenomenon that when two shadows, say projected on to a wall, approach eachother (for example by moving the light sources closer), at some point the shadows seem to merge as if they ...